使用jpa在postgresql数据库中创建主键自增表

Posted 2021-01-02 donfaquir

1. jpa依赖

    <!-- 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类

package com.hikvison.test.pgtest.entity;

import java.io.Serializable;

import javax.persistence.*;


import lombok.Data;

/**
 * 测试pg数据库的一些性能
 * 1. 主键自增
 * 2. 高并发锁机制
 * 
 * @date 2018年8月28日 下午7:23:17
 */
@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类

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类

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;

/**
 * 测试用contro
 * 
 * @date 2018年8月28日 下午7:35:25
 */

@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";
    }
}

增加数据库链接信息,数据库驱动,spring boot依赖,启动运行即可.

实现主键自增解析:

1. 在domain类中,使用了

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

其中:
1) test_sequence:数据库中的序列名,如果不存在,会创建,初始值为1,步长为1(postgresql和oracle一样,依赖序列实现主键的自增)
2)@SequenceGenerator,注意使用此注解声明序列.

有个问题:
我测试的表主键编号从50开始的,没弄清楚为什么.