[JAVA] 8 things to insert into DB using Spring Boot and JPA

8 things to insert into DB using Spring Boot and JPA

table of contents 0. Purpose of this time

1. Create a Spring Boot project
2. Prepare a DB in Mysql
3. PropertiesFile settings
4. Preparation of Entity class
5. Preparation of Repository class
6. Preparation of Service class
7. Preparation of Controller class
8. Confirm using curl
9. End

0. Purpose of this time

-** When I was just starting Spring Boot, I couldn't just insert into the DB using JPA. I didn't have an article that even cats could understand, so I'll write for myself at that time. ** ** --There is no explanation about special JPA, it's just an article about inserting into DB.

1. Create a Spring Boot project

--First, create a Spring Boot project -Access SPRING INITIALIZR

• Generate a [Gradle Project] with [Java] and Spring Boot [1.5.9] Set to -** [Group] ** and ** [Artifact] ** are appropriate. This time, the Group name is ** [com.jpa] ** and the Artifact name is ** [demojpa] **. -Set ** [Web] **** [MySql] **** [JPA] **** [lombok] ** to ** [Dependencies] **. --Please create with ** [Generate Project] **. --Expand the created project and open it in the IDE. (This time, I used Intel iJ IDEA)

2. Prepare a DB in Mysql

--Prepare a JPA test DB in MySql. ――This time, we prepared with such a configuration. --DB name is ** [jpa_test] **

CREATE TABLE `members` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(255) NULL,
  PRIMARY KEY (`id`));

3. PropertiesFile settings

--Open IDE --Open ** [application.properties] ** of ** [resources] ** directly under main in src ――Write the following three lines of magic and connect it to MySql. - spring.datasource.url=jdbc:mysql://localhost:3306/jpa_test --spring.datasource.username = MySql username --spring.datasource.password = password for MySql

4. Preparation of Entity class

--Create ** [domain] ** Package directly under main in src. -** [domain] ** Create ** [Members.java] ** in Package and write the following code.

package com.jpa.demojpa.domain;

import lombok.Data;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Data
@Entity
public class Members {
    @Id
    @GeneratedValue
    private Integer id;
    private String name;
}

5. Preparation of Repository class

-** [domain] ** Create ** [MembersRepository.java] ** in Package and write the following code.

package com.jpa.demojpa.domain;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface MembersRepository extends JpaRepository<Members, Integer> {
}

6. Preparation of Service class

--Create a ** [service] ** Package directly under main in src. -** [service] ** Create ** [MembersService.java] ** in Package and write the following code.

package com.jpa.demojpa.service;

import com.jpa.demojpa.domain.Members;
import com.jpa.demojpa.domain.MembersRepository;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Service;

@Service
@RequiredArgsConstructor
public class MembersService {
    private final MembersRepository membersRepository;

    public String create() {
        Members members = new Members();
        members.setName("hoge");
        membersRepository.save(members);
        return "success!!";
    }
}

7. Preparation of Controller class

--Create ** [web] ** Package directly under main in src. -** [web] ** Create ** [MembersController.java] ** in Package and write the following code.

package com.jpa.demojpa.web;

import com.jpa.demojpa.service.MembersService;
import lombok.RequiredArgsConstructor;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/members")
@RequiredArgsConstructor
public class MembersController {
    private final MembersService membersService;

    @PostMapping
    public String create() {
        return membersService.create();
    }
}

8. Confirm using curl

--Open a terminal and check with the following curl.

curl http://localhost:8080/members

-** [success !!] ** should be returned, please check MySql when it is returned.

9. End

--This is the end of 8 things *** for inserting into DB using Spring Boot and JPA. ――After that, ** [findOne] **** [save] **** [delete] ** is prepared in Jpa Repository, so please use it.

membersRepository.findOne(1);
membersRepository.save(members);
membersRepository.delete(1);