[Java知识库]mybatis-plus实现乐观锁

1.数据表增加version字段

CREATE TABLE `user` (
  `id` bigint(20) NOT NULL COMMENT '主键ID',
  `name` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '姓名',
  `age` int(11) DEFAULT NULL COMMENT '年龄',
  `email` varchar(50) DEFAULT NULL COMMENT '邮箱',
  `create_time` datetime DEFAULT NULL,
  `update_time` datetime DEFAULT NULL,
  `version` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

2.设置自动填充

package com.example.demo.entity;

import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.Version;
import lombok.Data;

import java.util.Date;

@Data
public class User {
    private Long id;
    private String name;
    private Integer age;
    private String email;
    @TableField(value = "create_time", fill = FieldFill.INSERT)
    private Date createTime;
    @TableField(value = "update_time", fill = FieldFill.INSERT_UPDATE)
    private Date updateTime;
    @Version
    @TableField(value = "version", fill = FieldFill.UPDATE)
    private Integer version;
}

3.乐观锁插件

package com.example.demo.config;

import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@MapperScan(basePackages = "com.example.demo.mapper")
public class MyConfig {

    /**
     * 旧版本乐观锁插件
     * @return

    @Bean
    public OptimisticLockerInterceptor optimisticLockerInterceptor() {
        return new OptimisticLockerInterceptor();
    }*/

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
        mybatisPlusInterceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        return mybatisPlusInterceptor;
    }

}

4.测试

package com.example.demo;

import com.example.demo.entity.User;
import com.example.demo.mapper.UserMapper;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

@SpringBootTest
class DemoApplicationTests {

	@Autowired
	private UserMapper userMapper;

	// 查询操作
	@Test
	public void findAll() {
		List<User> users = userMapper.selectList(null);
		System.out.println(users);
	}

	// 添加操作
	@Test
	public void testAdd() {
		User user = new User();
		user.setName("php");
		user.setAge(20);
		user.setEmail("123@qq.com");
		int insert = userMapper.insert(user);
		System.out.println(insert);
	}

	// 更新操作
	@Test
	public void testUpdate() {
		User user = new User();
		user.setId(1485617339597520897L);
		user.setName("mybatis");
		int i = userMapper.updateById(user);
		System.out.println(i);
	}

	// 测试乐观锁
	@Test
	public void testOptimisticLocker() {
		// 根据id查询
		User user = userMapper.selectById(1485627449220710401L);
		// 修改
		user.setName("rust");
		userMapper.updateById(user);
	}
}