Using JPA to create a primary key increment table in the PostgreSQL database

1. JPA Dependency

<!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-jpa -->
    <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-jpa -->
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-jpa</artifactId>
    </dependency>

1. Domain class

Package com.hikvison.test.pgtest.entity;

Import java.io.Serializable;

Import javax.persistence.*;


Import lombok.Data;

/**
  * Test some performance of the pg database
  * 1. Primary key increment
  * 2. High concurrent lock mechanism
  *
  * @dateAugust 28, 2018 7:23:17 PM
  */
@Data
@Entity
@Table(name="test_pg_wushan")
Public class TestEntity implements Serializable {

     Private static final long serialVersionUID = 2672553622864930471L;
     @Id
     @SequenceGenerator(sequenceName="test_sequence", name="abc" )
     @GeneratedValue(strategy=GenerationType.SEQUENCE,generator="abc")
     @Column(name="id")
     Private Integer id;
     @Column(name="test_name")
    
     Private String name;
     @Transient
     Private Integer version;
}

1. Repository class

package com.hikvison.test.pgtest.repository;

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

import com.hikvison.test.pgtest.entity.TestEntity;

public interface TestRepository extends JpaRepository<TestEntity, Long> {

}

1. Controller class

Package com.hikvison.test.pgtest.controller;

Import org.springframework.beans.factory.annotation.Autowired;
Import org.springframework.stereotype.Controller;
Import org.springframework.web.bind.annotation.RequestMapping;
Import org.springframework.web.bind.annotation.ResponseBody;

Import com.hikvison.test.pgtest.entity.TestEntity;
Import com.hikvison.test.pgtest.repository.TestRepository;

/**
  * Test contro
  *
  * @date August 28, 2018 7:35:25 PM
  */

@Controller
Public class TeatController {
     @Autowired
     TestRepository r ;
    
     @RequestMapping("/")
     @ResponseBody
     Public String test1(){
         Return "hello";
     }
    
     @RequestMapping("/save")
     @ResponseBody
     Public String test2(){
         TestEntity te = new TestEntity();
         te.setName(System.currentTimeMillis()+"");
         R.save(te);
         Return "success";
     }
}

Add database link information, database driver, Spring boot dependency, start running. Implement primary key self-increment parsing:

1. In the domain class, you use the

@Id
    @SequenceGenerator(sequenceName="test_sequence", name="abc" )
    @GeneratedValue(strategy=GenerationType.SEQUENCE,generator="abc")
    @Column(name="id")
    private Integer id;

which
1) test_sequence: The sequence name in the database, if it does not exist, will be created with an initial value of 1 and a step of 1 (PostgreSQL and Oracle, the dependent sequence implements the self-increment of the primary key)
2) @SequenceGenerator, note the use of this annotation to declare a sequence.

There is a problem:
I tested the table primary key number starting with 50, not figuring out why.

Using JPA to create a primary key increment table in the PostgreSQL database