CrudRepository save

Save method defined in CrudRepository interface is used to save an entity type or domain object. save method returns the instance of the saved object along with the primary key generated by the underlying database if programmed accordingly. entity passed in the saved method must not be null else it will throws IllegalArgumentException.

drop database if exists AppleDb;
create database AppleDb; 
use AppleDb;
create table apple (apple_id bigint not null, apple_name varchar(255), primary key (apple_id)) engine=InnoDB;
create table hibernate_sequence (next_val bigint) engine=InnoDB;
insert into hibernate_sequence values ( 1 )

package org.wesome.jpa.controller;

import org.wesome.jpa.entity.Apple;
import org.wesome.jpa.repository.AppleRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class AppleController {
    @Autowired
    private AppleRepository appleRepository;

    @GetMapping
    Apple save() {
        Apple apple = new Apple("Macintosh");
        Apple save = appleRepository.save(apple);
        System.out.println("save = " + save);
        return save;
    }
}

package org.wesome.jpa.entity;

import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

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

@Data
@ToString
@Entity
@NoArgsConstructor
public class Apple {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long appleId;
    private String appleName;

    public Apple(String appleName) {
        this.appleName = appleName;
    }
}

package org.wesome.jpa.repository;

import com.sujan.example.jpa.entity.Apple;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface AppleRepository extends JpaRepository<Apple, Long> {
}

package org.wesome.jpa;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class JpaApplication {
    public static void main(String[] args) {
        SpringApplication.run(JpaApplication.class, args);
    }
}

spring.datasource.url=jdbc:mysql://localhost:3306/AppleDb
spring.datasource.username=root
spring.datasource.password=root

plugins {
    id 'org.springframework.boot' version '2.3.3.RELEASE'
    id 'io.spring.dependency-management' version '1.0.10.RELEASE'
    id 'java'
}
group = 'com.sujan'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'
configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}
repositories {
    mavenCentral()
}
dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    annotationProcessor 'org.projectlombok:lombok'
    compileOnly 'org.projectlombok:lombok'
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    runtimeOnly 'mysql:mysql-connector-java'
    testImplementation('org.springframework.boot:spring-boot-starter-test') {
        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
    }
}
test {
    useJUnitPlatform()
}

select next_val as id_val from hibernate_sequence for update;
update hibernate_sequence set next_val= ? where next_val=?;
insert into apple (apple_name, apple_id) values (?, ?);

curl --location --request GET 'http://localhost:8080/'