Java Spring Jpa Crud Example

In this tutorial, we're gonna build a Spring Boot Rest CRUD API example with Maven that use Spring Data JPA to interact with MySQL/PostgreSQL database. You'll know:

• How to configure Spring Data, JPA, Hibernate to work with Database
• How to define Data Models and Repository interfaces
• Way to create Spring Rest Controller to process HTTP requests
• Way to use Spring Data JPA to interact with PostgreSQL/MySQL Database

More Practice:
– Secure Spring Boot App with Spring Security & JWT Authentication
– Spring Boot Rest XML example – Web service with XML Response
– Spring Boot + GraphQL + MySQL example
– Spring Boot Multipart File upload example
– Spring Boot Pagination and Sorting example

Associations:
– Spring Boot One To Many example with JPA, Hibernate
– Spring Boot Many to Many example with JPA, Hibernate

Fullstack:
– Vue + Spring Boot example
– Angular 8 + Spring Boot example
– Angular 10 + Spring Boot example
– Angular 11 + Spring Boot example
– Angular 12 + Spring Boot example
– Angular 13 + Spring Boot example
– React + Spring Boot example

Exception Handling:
– Spring Boot @ControllerAdvice & @ExceptionHandler example
– @RestControllerAdvice example in Spring Boot

Testing:
– Spring Boot Unit Test for JPA Repositiory
– Spring Boot Unit Test for Rest Controller

Deployment:
– Deploy Spring Boot App on AWS – Elastic Beanstalk
– Docker Compose: Spring Boot and MySQL example

Overview of Spring Boot JPA Rest CRUD API example

We will build a Spring Boot JPA Rest CRUD API for a Tutorial application in that:

• Each Tutotial has id, title, description, published status.
• Apis help to create, retrieve, update, delete Tutorials.
• Apis also support custom finder methods such as find by published status or by title.

These are APIs that we need to provide:

Methods	Urls	Actions
POST	/api/tutorials	create new Tutorial
GET	/api/tutorials	retrieve all Tutorials
GET	/api/tutorials/:id	retrieve a Tutorial by :id
PUT	/api/tutorials/:id	update a Tutorial by :id
DELETE	/api/tutorials/:id	delete a Tutorial by :id
DELETE	/api/tutorials	delete all Tutorials
GET	/api/tutorials/published	find all published Tutorials
GET	/api/tutorials?title=[keyword]	find all Tutorials which title contains keyword

– We make CRUD operations & finder methods with Spring Data JPA's JpaRepository.
– The database could be PostgreSQL or MySQL depending on the way we configure project dependency & datasource.

If you want to use JdbcTemplate instead, kindly visit:
Spring Boot JdbcTemplate example with MySQL: CRUD App

Technology

• Java 8
• Spring Boot 2.2.1 (with Spring Web MVC, Spring Data JPA)
• PostgreSQL/MySQL
• Maven 3.6.1

Project Structure

Let me explain it briefly.

– Tutorial data model class corresponds to entity and table tutorials.
– TutorialRepository is an interface that extends JpaRepository for CRUD methods and custom finder methods. It will be autowired in TutorialController.
– TutorialController is a RestController which has request mapping methods for RESTful requests such as: getAllTutorials, createTutorial, updateTutorial, deleteTutorial, findByPublished…
– Configuration for Spring Datasource, JPA & Hibernate in application.properties.
– pom.xml contains dependencies for Spring Boot and MySQL/PostgreSQL.

We can improve the example by adding Comments for each Tutorial. It is the One-to-Many Relationship and I write a tutorial for this at:
Spring Boot One To Many example with JPA, Hibernate

Or add Tags with Many-to-Many Relationship:
Spring Boot Many to Many example with JPA, Hibernate

Video

This is demo video and brief instruction of Spring Boot Rest Apis with Hibernate, MySQL example using Spring Data JPA:

Create & Setup Spring Boot project

Use Spring web tool or your development tool (Spring Tool Suite, Eclipse, Intellij) to create a Spring Boot project.

Then open pom.xml and add these dependencies:

          <dependency> 	<groupId>org.springframework.boot</groupId> 	<artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> 	<groupId>org.springframework.boot</groupId> 	<artifactId>spring-boot-starter-web</artifactId> </dependency>                  

We also need to add one more dependency.
– If you want to use MySQL:

          <dependency> 	<groupId>mysql</groupId> 	<artifactId>mysql-connector-java</artifactId> 	<scope>runtime</scope> </dependency>                  

– or PostgreSQL:

          <dependency> 	<groupId>org.postgresql</groupId> 	<artifactId>postgresql</artifactId> 	<scope>runtime</scope> </dependency>                  

Configure Spring Datasource, JPA, Hibernate

Under src/main/resources folder, open application.properties and write these lines.

– For MySQL:

          spring.datasource.url= jdbc:mysql://localhost:3306/testdb?useSSL=false spring.datasource.username= root spring.datasource.password= 123456 spring.jpa.properties.hibernate.dialect= org.hibernate.dialect.MySQL5InnoDBDialect # Hibernate ddl auto (create, create-drop, validate, update) spring.jpa.hibernate.ddl-auto= update                  

– For PostgreSQL:

          spring.datasource.url= jdbc:postgresql://localhost:5432/testdb spring.datasource.username= postgres spring.datasource.password= 123 spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation= true spring.jpa.properties.hibernate.dialect= org.hibernate.dialect.PostgreSQLDialect # Hibernate ddl auto (create, create-drop, validate, update) spring.jpa.hibernate.ddl-auto= update                  

• spring.datasource.username & spring.datasource.password properties are the same as your database installation.
• Spring Boot uses Hibernate for JPA implementation, we configure MySQL5InnoDBDialect for MySQL or PostgreSQLDialect for PostgreSQL
• spring.jpa.hibernate.ddl-auto is used for database initialization. We set the value to update value so that a table will be created in the database automatically corresponding to defined data model. Any change to the model will also trigger an update to the table. For production, this property should be validate.

Define Data Model

Our Data model is Tutorial with four fields: id, title, description, published.
In model package, we define Tutorial class.

model/Tutorial.java

          package com.bezkoder.spring.datajpa.model; import javax.persistence.*; @Entity @Table(name = "tutorials") public class Tutorial { 	@Id 	@GeneratedValue(strategy = GenerationType.AUTO) 	private long id; 	@Column(name = "title") 	private String title; 	@Column(name = "description") 	private String description; 	@Column(name = "published") 	private boolean published; 	public Tutorial() { 	} 	public Tutorial(String title, String description, boolean published) { 		this.title = title; 		this.description = description; 		this.published = published; 	} 	public long getId() { 		return id; 	} 	public String getTitle() { 		return title; 	} 	public void setTitle(String title) { 		this.title = title; 	} 	public String getDescription() { 		return description; 	} 	public void setDescription(String description) { 		this.description = description; 	} 	public boolean isPublished() { 		return published; 	} 	public void setPublished(boolean isPublished) { 		this.published = isPublished; 	} 	@Override 	public String toString() { 		return "Tutorial [id=" + id + ", title=" + title + ", desc=" + description + ", published=" + published + "]"; 	} }                  

– @Entity annotation indicates that the class is a persistent Java class.
– @Table annotation provides the table that maps this entity.
– @Id annotation is for the primary key.
– @GeneratedValue annotation is used to define generation strategy for the primary key. GenerationType.AUTO means Auto Increment field.
– @Column annotation is used to define the column in database that maps annotated field.

Create Repository Interface

Let's create a repository to interact with Tutorials from the database.
In repository package, create TutorialRepository interface that extends JpaRepository.

repository/TutorialRepository.java

          package com.bezkoder.spring.datajpa.repository; import java.util.List; import org.springframework.data.jpa.repository.JpaRepository; import com.bezkoder.spring.datajpa.model.Tutorial; public interface TutorialRepository extends JpaRepository<Tutorial, Long> {   List<Tutorial> findByPublished(boolean published);   List<Tutorial> findByTitleContaining(String title); }                  

Now we can use JpaRepository's methods: save(), findOne(), findById(), findAll(), count(), delete(), deleteById()… without implementing these methods.

We also define custom finder methods:
– findByPublished(): returns all Tutorials with published having value as input published.
– findByTitleContaining(): returns all Tutorials which title contains input title.

The implementation is plugged in by Spring Data JPA automatically.

You can modify this Repository:
– to work with Pagination, the instruction can be found at:
Spring Boot Pagination & Filter example | Spring JPA, Pageable
– to sort/order by multiple fields with the tutorial:
Spring Data JPA Sort/Order by multiple Columns | Spring Boot

More Derived queries at:
JPA Repository query example in Spring Boot

Custom query with @Query annotation:
Spring JPA @Query example: Custom query in Spring Boot

You also find way to write Unit Test for this JPA Repository at:
Spring Boot Unit Test for JPA Repositiory with @DataJpaTest

Create Spring Rest APIs Controller

Finally, we create a controller that provides APIs for creating, retrieving, updating, deleting and finding Tutorials.

controller/TutorialController.java

          package com.bezkoder.spring.datajpa.controller; import java.util.ArrayList; import java.util.List; import java.util.Optional; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.CrossOrigin; import org.springframework.web.bind.annotation.DeleteMapping; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.PutMapping; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; import com.bezkoder.spring.datajpa.model.Tutorial; import com.bezkoder.spring.datajpa.repository.TutorialRepository; @CrossOrigin(origins = "http://localhost:8081") @RestController @RequestMapping("/api") public class TutorialController {   @Autowired   TutorialRepository tutorialRepository;   @GetMapping("/tutorials")   public ResponseEntity<List<Tutorial>> getAllTutorials(@RequestParam(required = false) String title) {     try {       List<Tutorial> tutorials = new ArrayList<Tutorial>();       if (title == null)         tutorialRepository.findAll().forEach(tutorials::add);       else         tutorialRepository.findByTitleContaining(title).forEach(tutorials::add);       if (tutorials.isEmpty()) {         return new ResponseEntity<>(HttpStatus.NO_CONTENT);       }       return new ResponseEntity<>(tutorials, HttpStatus.OK);     } catch (Exception e) {       return new ResponseEntity<>(null, HttpStatus.INTERNAL_SERVER_ERROR);     }   }   @GetMapping("/tutorials/{id}")   public ResponseEntity<Tutorial> getTutorialById(@PathVariable("id") long id) {     Optional<Tutorial> tutorialData = tutorialRepository.findById(id);     if (tutorialData.isPresent()) {       return new ResponseEntity<>(tutorialData.get(), HttpStatus.OK);     } else {       return new ResponseEntity<>(HttpStatus.NOT_FOUND);     }   }   @PostMapping("/tutorials")   public ResponseEntity<Tutorial> createTutorial(@RequestBody Tutorial tutorial) {     try {       Tutorial _tutorial = tutorialRepository           .save(new Tutorial(tutorial.getTitle(), tutorial.getDescription(), false));       return new ResponseEntity<>(_tutorial, HttpStatus.CREATED);     } catch (Exception e) {       return new ResponseEntity<>(null, HttpStatus.INTERNAL_SERVER_ERROR);     }   }   @PutMapping("/tutorials/{id}")   public ResponseEntity<Tutorial> updateTutorial(@PathVariable("id") long id, @RequestBody Tutorial tutorial) {     Optional<Tutorial> tutorialData = tutorialRepository.findById(id);     if (tutorialData.isPresent()) {       Tutorial _tutorial = tutorialData.get();       _tutorial.setTitle(tutorial.getTitle());       _tutorial.setDescription(tutorial.getDescription());       _tutorial.setPublished(tutorial.isPublished());       return new ResponseEntity<>(tutorialRepository.save(_tutorial), HttpStatus.OK);     } else {       return new ResponseEntity<>(HttpStatus.NOT_FOUND);     }   }   @DeleteMapping("/tutorials/{id}")   public ResponseEntity<HttpStatus> deleteTutorial(@PathVariable("id") long id) {     try {       tutorialRepository.deleteById(id);       return new ResponseEntity<>(HttpStatus.NO_CONTENT);     } catch (Exception e) {       return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);     }   }   @DeleteMapping("/tutorials")   public ResponseEntity<HttpStatus> deleteAllTutorials() {     try {       tutorialRepository.deleteAll();       return new ResponseEntity<>(HttpStatus.NO_CONTENT);     } catch (Exception e) {       return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);     }   }   @GetMapping("/tutorials/published")   public ResponseEntity<List<Tutorial>> findByPublished() {     try {       List<Tutorial> tutorials = tutorialRepository.findByPublished(true);       if (tutorials.isEmpty()) {         return new ResponseEntity<>(HttpStatus.NO_CONTENT);       }       return new ResponseEntity<>(tutorials, HttpStatus.OK);     } catch (Exception e) {       return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);     }   } }                  

– @CrossOrigin is for configuring allowed origins.
– @RestController annotation is used to define a controller and to indicate that the return value of the methods should be be bound to the web response body.
– @RequestMapping("/api") declares that all Apis' url in the controller will start with /api.
– We use @Autowired to inject TutorialRepository bean to local variable.

Run & Test

Run Spring Boot application with command: mvn spring-boot:run.

tutorials table will be automatically generated in Database.
If you check MySQL for example, you can see things like this:

          mysql> describe tutorials; +--------------+--------------+------+-----+---------+-------+ | Field        | Type         | Null | Key | Default | Extra | +--------------+--------------+------+-----+---------+-------+ | id           | bigint(20)   | NO   | PRI | NULL    |       | | description  | varchar(255) | YES  |     | NULL    |       | | published    | bit(1)       | YES  |     | NULL    |       | | title        | varchar(255) | YES  |     | NULL    |       | +--------------+--------------+------+-----+---------+-------+                  

Create some Tutorials:

          mysql> select * from tutorials; +----+-----------------------+--------------+-------------------------+ | id | description           | published    | title                   | +----+-----------------------+--------------+-------------------------+ |  1 | Description for Tut#1 | 0            | Spring Boot Tutorial #1 | |  2 | Description for Tut#2 | 0            | Spring Boot Tutorial #2 | |  3 | Description for Tut#3 | 0            | Spring Boot Tutorial #3 | |  4 | Tut#4 Description     | 0            | Spring Data Tutorial #4 | |  5 | Tut#5 Description     | 0            | Spring Data Tutorial #5 | +----+-----------------------+--------------+-------------------------+                  

Update some Tutorials:

          mysql> select * from tutorials; +----+-----------------------+--------------+-------------------------+ | id | description           | published    | title                   | +----+-----------------------+--------------+-------------------------+ |  1 | Description for Tut#1 | 0            | Spring Boot Tutorial #1 | |  2 | Desc for Tut#2        | 1            | Spring Tutorial #2      | |  3 | Desc for Tut#3        | 1            | Spring Boot Tutorial #3 | |  4 | Tut#4 Description     | 0            | Spring Data Tutorial #4 | |  5 | Tut#5 Desc            | 1            | Spring Data Tutorial #5 | +----+-----------------------+--------------+-------------------------+                  

Get all Tutorials:

Get a Tutorial by Id:

Find all published Tutorials:

Find all Tutorials which title contains 'boot':

Delete a Tutorial:

          mysql> select * from tutorials; +----+-----------------------+--------------+-------------------------+ | id | description           | published    | title                   | +----+-----------------------+--------------+-------------------------+ |  1 | Description for Tut#1 | 0            | Spring Boot Tutorial #1 | |  2 | Desc for Tut#2        | 1            | Spring Tutorial #2      | |  3 | Desc for Tut#3        | 1            | Spring Boot Tutorial #3 | |  5 | Tut#5 Desc            | 1            | Spring Data Tutorial #5 | +----+-----------------------+--------------+-------------------------+                  

Delete all Tutorials:

          mysql> select * from tutorials; Empty set (0.00 sec)                  

You can use the Simple HTTP Client using Axios to check it.

Or: Simple HTTP Client using Fetch API

Conclusion

Today we've built a Rest CRUD API using Spring Boot, Spring Data JPA, Hibernate, Maven to interact with MySQL/PostgreSQL.

We also see that JpaRepository supports a great way to make CRUD operations and custom finder methods without need of boilerplate code.

Custom query with @Query annotation:
Spring JPA @Query example: Custom query in Spring Boot

If you want to add Pagination to this Spring project, you can find the instruction at:
Spring Boot Pagination & Filter example | Spring JPA, Pageable

To sort/order by multiple fields:
Spring Data JPA Sort/Order by multiple Columns | Spring Boot

Handle Exception for this Rest APIs is necessary:
– Spring Boot @ControllerAdvice & @ExceptionHandler example
– @RestControllerAdvice example in Spring Boot

Or way to write Unit Test:
– Spring Boot Unit Test for JPA Repositiory
– Spring Boot Unit Test for Rest Controller

You can also know:
– how to deploy this Spring Boot App on AWS (for free) with this tutorial.
– dockerize with Docker Compose: Spring Boot and MySQL example
– way to upload an Excel file and store the data in MySQL database with this post
– upload CSV file and store the data in MySQL with this post.

Happy learning! See you again.

Further Reading

• Secure Spring Boot App with Spring Security & JWT Authentication
• Spring Data JPA Reference Documentation
• Spring Boot Pagination and Sorting example

Fullstack CRUD App:
– Vue + Spring Boot example
– Angular 8 + Spring Boot example
– Angular 10 + Spring Boot example
– Angular 11 + Spring Boot example
– Angular 12 + Spring Boot example
– Angular 13 + Spring Boot example
– React + Spring Boot example

We can improve the example by adding Comments for each Tutorial. It is the One-to-Many Relationship and I write a tutorial for this at:
Spring Boot One To Many example with JPA, Hibernate

Or add Tags with Many-to-Many Relationship:
Spring Boot Many to Many example with JPA, Hibernate

Source Code

You can find the complete source code for this tutorial on Github.

More Derived queries at:
JPA Repository query example in Spring Boot

Using JdbcTemplate instead:
Spring Boot JdbcTemplate example with MySQL: CRUD App

Other Databases:
– Spring Boot, PostgreSQL: Rest Apis example with Spring JPA
– Spring Boot, Oracle: Rest Apis example with Spring JPA

sandersunry1947.blogspot.com

Source: https://www.bezkoder.com/spring-boot-jpa-crud-rest-api/

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