Spring Boot Tutorial for Beginners | Full Course 2025

What's going on guys Asalam allayikum  welcome to this course on Spring Boot. In this course I'm going to teach you the most popular  framework for the Java ecosystem Spring Boot which allows you to build Restful APIs and web applications and  all that good stuff in this course I'm going to teach you Spring Boot and we're going to learn  how to create an API connect to a real database using Docker um and a database will be Postgres  as well as using JPA so this is an overview of how to put all of these components together in  terms of building a real API all right so if you're new to this channel go ahead and subscribe  smash the like button so we can keep on recording content like this and without further ado let's  get started before I start just want to say that we just released our brand new platform Migos  Code 2.0 know and uh everything has been built from scratch new dashboard new courses new tools  um new content blogs and pretty much everything that you need in terms of helping you succeed  as an engineer so this is something that a lot of you have been asking and I felt in terms  of taking Amigos to the next level we had to build this brand new platform and in fact if you  want to gain a certificate this exact same course with exercises is available in our platform  so go and enroll all right so for now let's go ahead and learn about Spring Boot for this course  we're going to use IntelliJ which is by far the best IDE for Java and uh pretty much everything  that has to do with the JVM so in our platform actually if I show you we actually offer a 3  months free Intelligj subscription so literally go to licenses and then right here you should  see the actual key to use intelligj all right so once you have that you can go and redeem the  license and then you have access for free months so as well with Intelligj what I'm actually using  is the tool called toolbox so within this course here Intelligj developer guide I show you how to  get up and running with Intelligj and the best way is to install toolbox so in here if I click  on this icon you can see that in here I do have intelligj toolbox and basically this is how I  manage all of the licenses for jet brains IDEs so you can see IntelliJ Goland Community Edition  they also have free commercial use for Rusk Aqua and I think for yeah webtorm as well which is  quite nice rider as well fornet and uh yeah so go ahead and um install toolbox and then also  redeem your code for intelligj ultimate all right so once you do that which is very straightforward  in terms of installing IntelliJ through toolbox go ahead and let me know but what I'll do also is  I'll leave the links for everything that you need in the description of this video once you have  IntelliJ installed let's together create a new project by pressing on this button in here  then you'll be presented with this window and in here we have a bunch of generators that we  can use so you can see we have a standalone Java application Cotlin Go Maven we have Spring Boo  JavX Quarkos Ktor HTML React Express and all of that good stuff so for us what we need is Spring  Boot and then here just pick a location within your file system so I'm going to leave mine under  desktop and then here I'm going to say spring dash and then boot all right the other thing that I  want to All right the other thing is if you want to create a repository go ahead and say create  git repo and this makes sure that you have the actual code as a git repository that you can then  basically push to GitHub for example so in my case I'm going to do this and I recommend you to store  everything you learn so that you can use to build your portfolio the next thing is language so for  the language you can use cotlin if you want i do have a course on cotlin which is really nice  language but I'm going to stick with Java in here and then for the type you can choose gradal  with cotlin or groovy or maven so let's just use maven and for the group ID here I'm going to say  com.migos code so this could be your domain or organization or pretty much anything that you want  all right or if you want to have the same thing as me just say comam amigos code and then for the  artifact I'm going to leave as spring boot for the package name in here so what I'm going to do  is I'm going to remove spring boot i'm just going to have com amigos code and then within the root  I'll create basically some packages if I need to but I don't need a package called Spring Boot all  right so for JDK if you don't have JDK installed Java Development Kit click on this button and  then you can basically download a JDK so click on download and then here you can choose a version  so currently the latest one is 23 i think this is experimental basically I think long-term supported  versions are 21 17 11 and I think 1.8 if I'm not mistaken all right cool just download any version  that you want really and it should just work so in my case I'm going to cancel out of this and  you can see here I can pick the version so in my case I've got 17 21 and 23 installed so let's So  let's just pick 21 and in fact to make sure that everything works um with no errors just make  sure you have the exact same version as me so just download in here so download and then choose  21 and then for the vendor you could choose any all right so let me press escape and cancel and  then for the packaging just choose jar all right so basically this configuration right here you  can see the server URL is start.spring.io so if I click on this it brings up this website  and this is the spring initializer which is quite popular and basically Intelligj is just  using that to bootstrap your project all right let me go back and we're good to go click next  now we can choose the Spring Boot version just leave the default in here and then we can choose  dependencies so from here you can see that they have a bunch of dependencies so the most popular  one is web and this allows us to so if I so if I select web and you can see that allows us to build  restful APIs using spring MVC all right let's just select this one for now we'll come back later and  select other dependencies but for now let's just stick with this one and then say create and hooray  you can see that so let me just close this you can see that's indexing and it's done so I don't know  why I've got split pane in here let me just click on this button and we are good to go so from this  point onwards you can see that few things in here are red and green and this is because of git right  so I'm going to push all of this to GitHub so that you have access to everything at this point let's  stop here and if you have any issues feel free to let me know otherwise I'll see you in the next  one now let's go ahead and create our very first Spring Boot API so in here let me just close this  and if I show you within the pom.xml you can see that in here we have dependencies have a look  dependencies and if I put this full screen we have spring boot starter web so this allows us to  create APIs if I close this and then open project under src and this is a Maven project by the way  so you can see we have src main and then inside of main we have Java resources and then also we  have tests in here and you can see that we have one class in here called application tests and  this right here does nothing at the moment all right let me just close this and within Java  we have application and this class right here called application has this annotation right  here called spring boot application and within the main method spring application.run and then  we pass the application.class in here so as you'll see with Spring Boot as well as Spring Framework  it's all about annotations so understanding these annotations is crucial now for every single Spring  Boot application you will have this annotation in here which basically if I open this so I'm going  to press command and then navigate into it and you can see the keyboard shortcut for Mac OS as well  as Windows and Linux and this right here is an alias for enable auto configuration component scan  and I think the configuration so it's basically bundling these three annotations into one so yeah  so let me just close this now and to create your first API simply add a new annotation at and  then say rest and then controller and within this rest controller oops what am I doing there  we're going to so within this application we're going to create a new method so I'm going to say  public and then string and in here I'm going to say hello and then world and within here I'm  going to say return and I'm going to basically say hello and then world and then spring boot  all right with semicolon and in order for us to expose this right here as an endpoint i.e http  get so we need to say at and then get mapping so this method right here is a rest endpoint now what  we need to do in order to run this is let's just rightclick run or you can run from here from  here or from here so either one just run the application and if everything goes well you  should see that within the logs have a look tom card started on port 8080 with context path  and then forward slash now it means that we have a web server which is running on this port  and we can interact with it so let me just hide this and if you see within IntelliJ we have  a rest client that we can use so no need to use Postman or any other REST client so here we  can basically click on you can see this web icon in here i can click on it and we can  generate HTTP client in here so request in HTTP client i can do this or if I in here open  a project and what I'm going to do is so I want to so I want you to have access to this so here  under the root I'm going to say new and then we can basically say HTTP request so I'm going  to commit all of this so I'm going to say requests there we go and I'm going to and I'm  not going to add this as yet so I'm just going to cancel and then you can see that this is an  example of a get request if you want to have more examples you can see how to send post requests  put so on and so forth so in my case I want to send a request so a get request to HTTP and  then localhost 8080 so remember within the logs so so remember within the logs if I open the run  tab have a look Tomcat started on port 8080 and then this is the context forward slash so HTTP  the protocol local host so currently I'm running on my local machine and then the port is 8080 now  if I run this have a look we have hello world from spring boot and this is your very first API I with  Spring Boot all right if you have any questions feel free to let me know otherwise I'll see you  in the next one all right so what we want to build is this API in here where clients can send HTTP  requests using get post put and delete so get for getting data post for adding data put for delete  and delete for deleting data or resources so currently we have our API which is running on 8080  it's not doing much it's just saying hello world but this is the beginning then what we want to do  is we want to integrate a real database Postgress running on Docker and you'll see Docker in action  as well and following the integration with OpenAI so we want to use some AI capabilities within  our API ai is very popular these days so I want to show you also as part of this crash course how  to integrate AI with your Spring Boot applications all right so for now let's get started now let's  go ahead and define the model for our application where we want to have developers and then store  these developers into our database so we're not going to focus on the database for now that will  come later but now let's just define the model in here all right let's just open up IntelligJ  all right within IntelligJ let's go ahead and create a new class under our root package and  we're going to name this class as software and then engineer so this will be a class in here  and that's because later we're going to use Spring Data JPA we could use records but I'll use  records in a second when we send a request to our server so here let me just put this full screen  and let's define some properties so private and then here it's going to be a string or actually  let's just say integer and then ID which uniquely identifies an engineer and then private and then  string name and finally let's just keep it simple private and then here let's also have string and  then I'm going to say tech and then stack so this actually should be a list of strings but just to  simplify things when we start to store when we start to store data into our database instead of  instead of us having a one to many relationship we just store everything under text stack so  you'll see this in a second so now let's create a constructor so we're going to have so basically  if I right click generate and then constructor so here we can actually select every single property  but also let's just first select none so we have the no R constructor and then here right click and  then generate and we're going to say constructor select everything and then say okay and then here  I'm going to grab this Ctrl G put this on new line and this is because my font is quite big so so  I usually don't have the font this big and next let's generate the getters and setters select  everything okay And finally let's just have the equals and hash code so equals and hash code there  we go and that's it now I'm not going to have the to string because it's not advisable once we  start to work with Spring Data JPA but again you'll see all of this in action in a second  all right this is pretty much the class that we need to store software engineers so next let's  go ahead and define the controller so that we can create an API that we can have maybe two software  engineers so for now I'll see you in the next one now that we have this model right here called  software engineer let's go ahead and start to build our API so here I'm going to create a new  class and I'm going to say software engineer and then controller so with spring boot and spring  this is the naming convention so anything that accepts requests from the clients or exposes rest  api expo or exposes rest endpoints you should name them as controllers so here I'm going to press  enter and remember before within our application we had the at rest controller so within our  software engineer controller in here we're going to say at and then rest controller now for  this rest controller we have to define at and then request and then mapping and we're going to say  software software and then engineers there we go and if you want to say API slashv1 for versioning  you're more than welcome so now let's create a method in here that will return that will return  software engineers so public and then list so list of in here so I'm going to say import class and  then here I'm going to say there we go and then this will return software so software oops and  then engineer and then get engineers just like this and let's just return list of and then here  I'm going to say new software engineer and we're going to pass ID1 and then the name let's just  say Jamesa and then the text tag for James going to be JS node and then react And then tailwind  tailwind CSS something like this let's have let's have someone else so comma oops and then take this  there we go this will be ID 2 this will be Jamila for example and Jamea she's a Java back end so  Java and then Spring and then Spring Boot just like that and then remove this now obviously  this could go on and on and on but let's keep it simple and this would semicolon right here  and we're good to go the last thing we need to annotate this method with at mapping so for  retrieval so get requests get mapping to delete put mapping to update to delete delete mapping  for post post mapping for put and then mapping for us we want to have this as get mapping and  we're good to go let's now start the application there we go up and running let me hide this and go  to requests.http and if you want to send another request so just copy that and then you have to  denote this with the hashtag so three hashtags denotes a separate request and then here I'm  going to say for slash API v1 and you can see that we get autocomp completion perfect if I send  the request you can see that we have the result and this is an array of objects so this is JSON  and you can see that this is actually handled for us like magic so this is the power of Spring  Boot we don't have to define any configuration in terms of how to encode and decode JSON objects  everything just happens for us behind the scenes and to be honest this is pretty much it all  right now that we have the API that obviously we're going to evolve later in here we're going  to have as part of the exercise i think we're going to have a delete mapping a put mapping so on  and so forth but this is taking shape so for now I'll see you in the next one for this section in  here I want to show you how to get up and running with databases Docker and Postgress so we want to  install a database using Docker in here and the database engine will be Postgress and then you'll  see how we can store developers to our database but also get developers of our database now here  getting developers of the database doesn't mean really removing but it's just a slice that you  see here but also as part of the exercises later I'm going to give you a task to delete of your  database and also update of your database all right that's all for now i'll see you in the next  one in this section let's learn what Docker is and how we can get a Postgress database up and running  with Docker docker is a platform for developing shipping and running applications in lightweight  portable containers so why use Docker well Docker gives us portability runs consistently across  environments uses fewer resources than virtual machines easy to deploy multiple instances  of the application it keeps applications and dependencies separate and also rapid startup  and deployment with pre-built images so when it comes to deployment especially when you combine  with Kubernetes this is a technology that you should know Docker all right so let's go through  some of the key concepts about Docker so we have containers so these are lightweight standalone and  executable package of the software so this could be Postgress this could be uh Java this could be  Python this could be your own application package into a container so this is the executable then we  have images so this is a snapshot of a container so from the image you create a container and  this image contains everything needed to run the application next we have the Docker file  so this is a script defining how an image is built so it's just a set of instructions on how  this image is built and then from this image we can run containers and then we have also docker  compose so this is a tool for defining and running multicontainer applications so you'll see this in  action docker compose and then we have registries so these so these are repositories for storing  and distributing docker images so we have many but the most popular one is Docker Hub but there are  other container registries provided by Amazon AWS as well as GCP Azure and whatnot all right this is  pretty much an introduction to Docker next let's go ahead and install Docker all right to get up  and running with Docker is really straightforward just navigate to their official website and  then they have some explanation what Docker is and whatnot but here also you can see that you can  download Docker desktop so it's quite interesting so Docker is the number one most used developer  tool so I actually didn't know this and I think they're quite right to be honest so in terms of us  installing Docker we could do it through here so if you want to learn more about Docker also if you  click on developers you can go to documentation and in here you can basically get docker as well  so if I click on get docker it takes us to this page in here and then you can download for Mac  Windows as well as Linux all right so go through the operating system of your choice so I'm on  a Mac i just click on Mac and then here you can see that I can download for the Apple silicon or  Intel chip and also Windows in here you could just find the correct installation but go through the  installation process it is very straightforward and once you install Docker I'll see you in the  next one all right once you have Docker installed you should see Docker Desktop so here let me  just open Docker desktop in here and it's an application that looks like this so here you can  see the list of containers images volumes builds extensions and whatnot so currently I only have  one or actually have a and currently I have few containers up and running in here so this is stuff  to do with Superbase but I'll show you how we can get our container up and running in a second so  once you have Docker Desktop you should be good to go but also one thing that I want you to do is  if you open up the terminal and then I want you to type docker- dash and then version all right so  this right here is the current version of Docker that I have installed maybe for you it might be  something way higher than this i can't remember the the last time that I actually updated Docker  but you should have the output like so and this means that Docker is now successfully installed in  your machine with this it means that you can say Docker and then image or images you can basically  say Docker ps as well and some of the available commands that Docker has to offer cool one other  command that we're going to use is docker compose that you'll see later but um this is pretty much  it and I'll see you on the next one all right so in here I'm inside of the docker registry and this  is where we can find the docker images that we can run containers from and here you can see that they  have a bunch of images so for machine learning and AI OAMA PyTorch TensorFlow and you can see  that they have Alpine EngineX MySQL Postgress so literally they have a bunch of containers in here  that you can use so the one that we actually need is this one called Postgress so let me just click  on that and you can find the link for this under description of this video so here you can see that  they've got these tags in here so 17 so these are the versions actually but also you have always  latest in here all right so latest so what I want to do is let's go ahead and open up intelligj  and within intelligj let's open up project and what I'm going to do is under the root folder in  here spring boot i'm going to create a new file and we're going to name this as docker dash and  then compose dot and then yaml all right now under the description of this video you will find the  contents for this YAML file so just copy and paste all right perfect so once you do that you should  have this in here and this basically is just a way of defining the containers that we want to manage  with Docker so here instead of writing the command so docker and then run I'm just using docker  compose so here I'm defining one service called database i'm naming it as posgress and you can  even say posgress dash and then spring boot so I think maybe I do have a database called postgress  so also this is the image so postgress oops not that but postgress and then latest so this is the  version right so within DockerHub in here you saw that we have the versions or tags so 17.2 17  latest and whatnot so if I go back I'm going to keep this as latest and then here I'm defining  the Postgress user the password and then where I'm actually storing the data and then some volumes  and then the ports in here so by default Postgress runs on 5432 but I'm changing this to 5332 because  some people might have this port already in use and I've been getting a lot of questions that  basically I cannot run Postgress on docker because it doesn't connect and it's because of this right  so you can change this port to anything but this one has to be 5432 and then some networks and then  the restart policy see in here and uh this is the network so if you have more than one container and  you want them to talk through the same network you can just um define network like so and then  use it and then this is the volume and to be honest it's as easy as this now let's go ahead in  here and open up terminal right within Intelligj and I'm going to say ls and you can see that we  have the docker compose.yammo and now I can say docker compose and then dash and then up dash  and then d so d for detached so if you execute this command you should see that we have network  created volume created and then postgress spring boot and then started all right now what I want  to do is I want to say docker compose and then ps and if you see here have a look we have one  container which is running postgress- spring boot and this is listening on localhost 5332 this is  the image in here and basically is up and running so what we're going to do also is if you want to  check the logs for this container we can do as follows you could just say docker compose and then  logs press enter and have a look database system is ready to accept connections and with this we  have a database up and running hooray now that we have Postgress running on Docker next let's go  ahead and connect our Spring Boot back end to our database so let's open up IntelligJ and in here  let me hide this and if I and if I open a project what we're going to do is under src main resources  and under pom.xml we need to add few dependencies so here you can see that we have this button  called add status click on it and it brings this window that you've seen before and if I go to  web you can see that spring web is selected that's the one we did before but we want to work with  SQL and databases but we want to work with SQL databases just go to SQL and then here we want  to choose both SQL driver so a JDBC and R2 DBC driver that allows Java programs to connect to  PostgresQL database and also we want to use this right here spring data JPA so this in here allows  us to persist data in SQL with Java persistence API using Spring Data and Hibernate you'll  see this in a second all right perfect just press okay and we're good to go so this actually  reloads the changes and sometimes if you add these dependencies manually you have to reload changes  so if I scroll down you can see that in here we do have the dependencies that we added so in fact you  can grab this from the description of this video and copy and paste but if I remove these you can  see that this button shows up sync maven changes so I just do it so you can see now say that you  paste from description of this video and then you have to sync Maven changes like the like that but  technically you don't have to use this button in here if you don't want to all right so this is it  next let me go ahead and restart the application and this will fail and you can see that in here  fail to configure data source URL well that's because we need to add the configuration and  tell our Spring Boot backend how to connect to the database i.e the URL username and password  all right so for now I'll see you in the next one okie dokie so in terms of configuring the  application to connect to our database let's hide this and then I'm going to go to project open up  src main resources we have application.properties properties open that up and in here we can specify  configuration that defines how our application behaves so here we have application name if you  want to change this to whatever name that you have or the name of the service that you are building  go ahead and do so so in my case I want to specify spring data and then source so you can see that  under data source so data source dot we have few things so we have the URL which we want to specify  so this will be JDBC colon for and then postgresql colon/ slash localhost colon and then 5 4 or 5332  so remember if I open docker compose remember this in here that we done 5332 so this is what we need  all right so let's go back and also actually let me just show you so if I open up the terminal so  remember if I say docker compos ps have a look so this is what we need locost 5332 so let me go back  in here and 5332 and then here I'm going to say forward slash and then amigos so we need to create  this database within our database server in a second but I'll show you how to do it next we need  to define the data source dot and then password so this is going to be password and also duplicate  this and we need the username and this will be amigos code amigos code amigos code like so and  basically within docker compose the username is amigos code and the password is password like so  all right let me go back all right now let me go ahead and define few things so this is more to do  with JPA but if I try to start the application it will fail so here we need to specify JPA dot  and then hibernate and then auto DDL so here I'm going to say create drop so this basically  will wipe the database every time that we start the application and also we need to specify JPAN  properties and the property that I want to have in here is the dialect so the dialect for this is  going to be org dot and then hibernate dot dialect dot and then postgrql and then dialect and we  can format the SQL as well so here I want to say hibernate and then formats SQL and this is going  to be true so you'll see all of this in a second and to be honest you don't have to type none of  this so I usually don't remember much of this and uh I just copy and paste from project to project  and also we need to show SQL so let's just say true and I think finally what we need is so in  here sometimes it asks us for the driver so let's just say yes so the driver name so I think this  is driver and you can see that because it has it in the class path it encounters the it finds the  postcresql driver and to be honest this should be it now let's try and start the application  and by the way just grab all of these from the description of this video and you're good to go  now if I start the application so I'm going to run the application and this will fail so if I  scroll up you can see that database amigos does not exist have a look does not exist so this  is actually very straightforward to fix and uh let's go ahead and create this database  in the next video in order for us to create this database called amigos we can do it by  specifying a property here that overrides the default database name or if you want we can also  create it manually so or if you want we can do it manually to do it manually or if you want we can  do it manually so let's just open the terminal and in here we can say docker compose and then  ps grab the name of the container running say docker and then exec-it or ti paste the name  and then say bash and then compose and then ps the name of the container which is running  the database and then say docker and then exec-it so dash dash it if I'm not mistaken and  then paste the container name and then say bash press enter and it looks like it's not d-it but  I think it's dash ID there we go so now you can see that we are in so if I type psql we cannot  connect to the database as root so if I clear the screen ctr l now if I say psql dash and then  u in here for the username amigos code press enter you can see that now we are inside perfect now  if I say back slashl you can see that we have all of these databases now theoretically so you  can see amigos code postgress and then template zero and whatnot now obviously here I could have  just said basically if I go back I could have just said amigos code in here but I didn't want to do  that because you might have a different username so basically it takes the username and it creates  the database of that username so basically maybe the username is fu and the database name is bar  so therefore it would have failed anyways right so now you know what is going on so let me just  press Q in here ctrl L and I want to say create and then data base and here I want to say amigos  and then end this with semicolon press enter and we're good to go now this should be amigos and  let's try and start the application and this time you can see that hooray we managed to connect  to our database so if I put this full screen in here what I want to show you is have a look  so this in here has to do with the database so Ekari data source starting added connection  and then started completed and you can see that all right so we don't have to specify the  dialect anymore which is fine and we're good to go so the application started on port 8080  so this is actually telling us so if I go here It's telling me that I don't need this anymore  so let's just get rid of that restart and you can see that error went away and we are good to  go perfect this is pretty much it now in here basically if I say back slash L you can see that  we have the database called amigos if you want to connect to it back slash C and then amigos and  now we are connected to Amigos and then we can perform an insert statement and all of that good  stuff which I'll show you in a second all right so we can use SQL in here to add data and then use  our API to fetch data from and then use Spring Boot to fetch but you'll see how to perform CRUD  with Spring Boot all right let me hide this and this is pretty much it i'll see you on the next  one so far we have our Java class in here with three properties ID name and text stack and what  we want to do is the ability of storing data so storing software engineers into our database so  effectively we want to use spring data JPA and then map this class in here taking all of the  properties ID name text stack and then create a table onto our database so here you can see ID  name and then text stack now we're not going to create the tables ourselves we're going to let  Spring Data JPA do all of this for us so Spring Data JPA is a framework that simplifies database  interactions by providing a high level abstraction over JPA and this allows us to reduce boilerplate  code and it provides also easy implementation of CRUD operations so we don't have to write any SQL  whatsoever and it's much easier to work with all right let's go ahead and learn how to integrate  this within our application within Intelligj what I need to do is to open the software engineer  class and in order for us to get up and running with JPA and then be able to perform credit  operations using the classes provided by the framework we need to first annotate this class  in here with at and then entity so we're going to name this as at and then entity and you can  see that we have you know a special icons in here and also this now is complaining so it says that  persistent entity must have a primary key so what we're going to do here is for the ID we're going  to say at and then ID just like that and now you can see that here we have a so this basically  it's an entity so basically if I click on it it shows and here you can see that we have the  key denoting a primary key and this right here and this sorry the text stack name and ID these  now are columns in our database so it's as simple as this now if I restart the application  what I want you to see is the following so if you see now we have create table  software engineer ID integer not null name text stack and we have a constraint in  here of primary key which is really nice so by just adding those two annotations we get a  table created in our database so if I in here show you something so remember within the so  within the resources application.properties so remember we added JPA hibernate DDL auto  so basically this every time that we restart the application it destroys the schema and it  creates it again in here formats SQL and then show SQL so if I remove these you won't be  able to see the SQL so the SQL with the SQ the SQL which is in here all right so this  is basically what these properties are doing so one other thing I want to show you is if I  navigate to the terminal and in here remember I'm connected inside of my database and in fact if  I say back slash q and then back slash or actually uh control c or no sorry ctrl d two times and  if you want to bash into the container so we say docker exec it and then postgress spring boot and  then bash and then type psql- U and the username that I defined under docker compose so my username  was here postgress user amigos code so just type amigos code perfect now we have a database called  amigos i'm going to say back slash c and then amigos so we are connected to amigos and now if  I click the screen I can type back slash and then d software and then engineer press enter  and you can see that we have a table called software engineer and you can see the types in  here so on and so forth perfect so this is cool next what we're going to do is I'm going to show  you how to fetch data from our database in here so for now if you have any questions drop a message  otherwise I'll see you on the next one in order for us to interact with this underlying table  in here called software engineer and the public so this is the schema from our spring boot API  we need to create a class so in here let's say create new and then this will be a class and the  type will be interface and here I'm going to say software and then engineer and then repository all  right so this interface in here we're going to so let me just hide this we're going to say extends  and then here we can say JPA and then repository so we have JPA repository and also we have CRUD  and then repository so let's use JPA repository so JPA repository and here so on a new line  actually because my font is quite big this takes few things so first it takes T so if you  work with generics so this should be familiar in here so T so here this will be software engineer  and then we have to specify the data type for the key so the data type for this entity so for the  actual key is integer so let's just go back and then say integer so integer just like that and  we're good to go now there's also uh some other interfaces that you can explore and um basically  extend but for this crash course let's just worry on let's just use JPA repository and this is more  than enough and I'll leave some instruction and I'll leave some text in terms and and I'll leave  and I'll leave a comparison between these other interfaces that you can explore cool now let's go  to project and within project and within project let's create a new and then java class and this  will be software engineer and then service so this class will handle everything that has to do  with business logic perfect here let's just say add and then service so this annotation right here  it basically makes this class available as a bean so that basically spring instantiates it and then  it makes it available to use within other classes all right the other thing that I want to do here  is I want to say private and then I want to get the repository that we've just created so software  engineer repository and then just call it software engineer repository so long name I know and now  here we're going to add this to the constructor like so and so this is the danger when you have  like big names so things don't really fit on the screen and it's kind of and it's kind of ugly  but hopefully you can see it properly all right now let's have a method so here I'm going to say  public and then list of and then software engineer and let's import that class and I'm going to say  get and then software engineers perfect now this method in here is going to use the repository so  we're going to say return and then the repository so software engineer repository dot and then have  a look so we have find all we have find by ID or find all by ID and then get software engineer  by get by and then find by save count exists find by ID find one so on and so forth and you  can see that this is really straightforward and behind the scenes it's just writing some SQL to  fetch data for us so think about what do we need right now so we want to get all software engineers  well for that we could just say in here find and then all so we have a couple implementations in  here so find all and then we can pass an example but for us let's just say find all nice and easy  and we're good to go now let me just uh say that actually let's just make this final so in here  we are returning software engineer which is an entity usually you don't want to do this usually  you don't want to do this you want to map into a DTO so data transfer object for the client because  let's say that this class in here has for example a password or it has things that you don't really  want to return to the client so so by doing this you are exposing pretty much your table so usually  you'd have a DTO and then you say dot and then stream so stream oops so stream dot and then map  and then you map to a class that you can a class that you can then return to the client but for us  this is very straightforward and simple and if you want to learn more about this I cover this in all  of the other courses perfect so find all and let's now open up the controller so software engineer  controller and before remember we add these two but now what we're going to do is let's get rid  of all of these and instead what we're going to do is we're going to use the software engineer  so software engineer service and you can see that Intelligj is quite clever and it brought the class  in here as well as the constructor dot and then get software engineers so this actually should be  get all software engineer so this should so this should actually be get all software engineers so  let's just say get and then all software engineers get and then all software engineers nice and easy  cool and to be honest this is it if I restart the application and then remember we have the so this  file in here so requests.http and let me just hide this if I get have a look we get an empty array  and this is because the table is empty cool let's carry on on the next video so you saw that the  array is empty and this is because if I open up the terminal and within my database I can say  select star from software engineer and have a look we have zero rows if you want to insert just  say insert into and then software engineer and then here I'm going to say name comma and then  tech stack and here I'm going to say values and let's just say here James and make sure that this  has single and make sure that and make sure this and make and make sure that this is single quote  and then the text stack let's just say JS comma and then node comma and then react for example  and in here parentheses now if I try and save this this will fail because it says no value in  column ID so open up the so we have to change the software engineer and here we just specify the ID  but if you want the ID to be autogenerated just say at and then generated value and we specify  the strategy and the strategy is going to be identity so if you want a sequence you can  have a sequence and if you want a UID you can also have a UID but I think we could just  say identity in here and then if I refresh this I think this should work so if I open up the  terminal clear the screen and then press enter and you can see that it works perfect so if I add  someone else so here let's just say Jamila so Ja and Jamea she she's into let's just say Java and  then spring press enter and now I can say select star from software engineer press enter and you  can see that we have one and then two so this is what this is doing all right so by just having  the ID the keys do not auto increment Perfect so if you want a UID just change this to a UID  and job done and with this if I go to services and actually let's just go to our requests.http  and before we got an empty array now if I send the request haha have a look we are reading data  from our database so James and then the text stack is JS Node React Jamila Java and then Spring cool  this is pretty much it i'll see you in the next one okie dokie now let's go ahead and implement  the ability of adding new software engineers through an API endpoint so let's begin by defining  the endpoint so here we're going to say public and then void we're not going to return anything and  this will be add new software and then engineer and here we're going to accept a software engineer  so here I'm going to say software engineer there we go and in here have a look we are basically  accepting the entity so remember this right here is an entity so usually we don't want to do  this but for the sake of this video let's just uh use this nice and easy and it works and also  we cover with other courses and bills that we have the way of doing this with DTO so data transfer  objects so the same way that goes from server to client the same goes from server or the same  applies for client to server perfect now in here I want to say software engineer and then dot service  and then dot and I'm going to say insert software engineer and then pass the software engineer nice  and easy and in here if you put your mouse in here you can see that you can create the method in the  service class so let's just do that and there we go software engineer let me just put this on a  new line and as I said my font is quite big cool the other thing that we need to do is to simply  invoke the repository so repository dot and then guess what save and then we're going to save the  software and then engineer nice and easy so here we're not even doing validation checking whether  the values are not null and all that stuff which you should do but this allows us to but this  allows me to demonstrate how to build a cred API which is the power of spring boot which is  so quick cool so let me just go back into the controller and one thing that we need to do  within the controller is we have to annotate this with guess what at and then post mapping  nice and simple and job done so let's reload the application perfect let's go back to our  request.http and if you want to send a post request it should be as simple as adding a new  request and then you can say post and obviously in here the URL is going to be the same and if  you want to find out how to send a post they've got examples click on examples post requests and  here we could just basically take this example and then take this and then pass it in here  remove the URL in here and we're good to go now for us we want to pass the name so let's just  say JA and Jame's into Java and then Spring Boot and let's just say Spring for example cool now  one thing I want to show you is so you see that we have a post request and then here content type  application.json JSON this is the JSON object and if I show the examples once more so post request  examples have a look send post with request send post request with JSON body so this is the body  now we want to take the body that we have in here so this is the JSON body and this should be  actually text stack so whoops tech and then stack so we want to take this body right here and within  the controller so within the controller so right here we want to map into a J into a Java class so  the way we do it is by saying at and then request body nice and easy let's reload the application  once more and then go back to requests.http for HTTP and we can send this request so if I send  this request you can see that hooray 200 status code and now if I send a get request in here  so get all software engineers you can see that we have one JA and basically it's working so  let's just send in here Alex and Alex in and Alex is into K DB and here and then databases  and then and then Q so if I send this request you can see that 200 status code it worked if I  select here get and basically play this you can see that we have Alex in here so this is coming  from our database and I'm not lying to you so if I go to terminal and let me clear the screen select  start from software engineer and you can see that it's been stored correctly and we have basically  getting this data using spring boot and sending it back to the client cool this is pretty much it  if you have any questions drop a message otherwise I'll see you in the next one say that you want  to get a software engineer by ID so let's learn how to do that so here I'm going to hide and I'm  going to go to the controller and we're going to have another method so here let's just basically  take all of this paste and then I'm going to say get software engineer by ID and from the client  we're going to receive the ID so integer and then ID and this is going to be at and then path and  then variable and we need to in here specify the variable so just have double quotes and then curly  brackets and then say ID so when the clients they send the request they say forward slash and then  id and I'll show you this in a second now we can take this ID and then here we can say get and then  software engineer so engineer by ID I can create this so put the mouse in here and then create  method and here so this method actually let me actually delete this and do it again so we need  to pass the ID inside so ID now let me just put the mouse in here again create the method and you  can see that it gets sent through perfect so now we need to say return so return and then software  engineer repository guess what so can you think of the method that we need so we have find find all  and then here we have ah have a look have a look have a look find by ID hooray cool so let's just  in here say find by ID and then here we're going to pass the uh ID now this will fail and that's  because we are not really returning a list but we want to return the software engineer and here  what we're going to do is say dot and then or else so or else we want to throw so or else throw  an exception and then basically new and then illegal let's just say illegal is a state  exception but obviously this is not the right exception that we should be throwing and we  cover exceptions in detail so oops sorry my font is quite big and uh we get these helpers in here  so this is not JavaScript just like that that's why so here I can say so let's just um on a new  line we can say id plus not found just like that just like that and we semicolon and we're good  to go so if we go back to the controller and this should return the software engineer like that  and the error goes away perfect let's just rerun this there we go if I open up the HTTP client  let's just send Alex done alex has ID one so if you want to send the get request with ID one  all you do is take this and I'm going to paste it right here and then say forward slash and then  one nice and simple send the request and you can see that we have Alex in here now if I say two so  this will fail and we have in here the error now obviously this is not a 500 and by default this  is how it's implemented and obviously you want to change this to HTTP status code 404 and this  is something that we cover in great detail within our building spring boot APIs course but I'm going  to leave it here this is pretty much it i'll see you in the next one hopefully now you can see the  power of Spring Boot if you want to continue with the exercises there's an exercise where I want  to challenge you in terms of building the rest of the API go ahead and enroll on the website  where you can find the exercises as well as with solution and uh basically this course is  part of the massive road map that we have for the Java and Spring Boot developer so basically  we have a bunch of courses that basically takes you through from complete beginner all the way  to deploying your applications to AWS including Docker Kubernetes and um basically the the whole  sheban really all right it's all for now as always don't forget to smash the like button comment  down below and I'll see you on the next one

Learn how to build real-world backend applications with Spring Boot in this hands-on crash course. Whether you're new to Spring Boot or want a solid refresher, this tutorial covers everything you need to start building Java-based REST APIs with Spiring Boot, Spring Data JPA, PostgreSQL, and Docker. Want certificate? Enrol here - https://bit.ly/3EvZG9w 🔧 What you'll learn: - How to create REST APIs using Spring Boot and Spring MVC - Connect Spring Boot to a real PostgreSQL database using Docker - Use Spring Data JPA to interact with your database - Set up a full development environment with IntelliJ and Maven - Build clean, testable, and scalable backend services - Understand Docker, Docker Compose, and containerized DB setups 🛠 Technologies used: - Spring Boot - Java 21 - IntelliJ IDEA - Maven - Docker & Docker Compose - PostgreSQL - Spring Data JPA 📚 This course is part of the full Java Developer Roadmap available at https://www.amigoscode.com/roadmaps, where you can practice with exercises and earn certificates. 👉 Chapters included: Use the timestamp chapters below to jump to specific sections and follow along with ease. [00:00:00] - What You'll Learn in This Spring Boot Course [00:01:53] - How to Get Free IntelliJ Ultimate License [00:03:20] - Create a Spring Boot Project with IntelliJ [00:05:15] - Setup JDK and Maven Configuration [00:07:12] - Select Spring Boot Dependencies [00:09:46] - Build Your First Spring Boot API Endpoint [00:11:18] - Test API with IntelliJ REST Client [00:14:21] - Spring Boot Project Roadmap Overview [00:15:35] - Define Your First Java Model: Software Engineer [00:18:23] - Build Software Engineer Controller [00:20:54] - Test the REST API Returning JSON [00:22:55] - Introduction to Docker for Java Developers [00:24:11] - Key Docker Concepts: Containers, Images & More [00:26:12] - How to Install Docker and Docker Desktop [00:28:41] - Find and Use Postgres Image from Docker Hub [00:30:02] - Create docker-compose.yml for Postgres [00:32:01] - Run Docker Containers with docker-compose [00:33:43] - Add Spring Data JPA and PostgreSQL Dependencies [00:36:29] - Configure application.properties for Postgres [00:40:16] - Fix "Database Does Not Exist" Error [00:42:33] - Verify Table Creation in Postgres CLI [00:44:59] - Map Java Class to Database Table with JPA [00:47:09] - Auto-Generate Tables from Java Classes [00:50:07] - Create a Repository Interface for CRUD Operations [00:52:18] - Write a Service to Fetch All Software Engineers [00:55:59] - Connect Controller to Service Layer [00:56:36] - Test API to Retrieve Data from Database [00:59:46] - Add New Engineers with a POST Endpoint [01:04:15] - Handle Request Bodies with @RequestBody [01:06:42] - Get Software Engineer by ID (Path Variables) [01:08:17] - Handle Errors When Engineer Not Found [01:10:40] - Final Challenge and Roadmap to Mastery P.S =========================================== 💯 Don't forget to subscribe | http://bit.ly/2HpF5V8 💯 Join Private Facebook Group and Discord - https://amigoscode.com/p/join-community 💯 Follow me on Instagram | http://bit.ly/2TSkA9w ❤️ Thanks for watching #springboot #springboottutorial #springboot3