MyBatis-Plus之乐观锁案例

1.数据库表中添加乐观锁标记字段

2.实体类中添加对应的字段，并用 @Version注解设定当前字段为乐观锁标记字段

package com.example.domain;

import com.baomidou.mybatisplus.annotation.*;
import lombok.Data;

@Data
@TableName("users")
public class User {
    @TableId(value = "id",type = IdType.AUTO)
    private Integer id;
    @TableField(value = "name")
    private String name;
    @TableField(value = "number",select =false)
    private String number;
    @TableField(exist = false)
    private Integer online;
    @TableField(value = "deleted")
    @TableLogic(value = "0",delval = "1")
    private Integer deleted;
    @Version
    private Integer version;
}

3.在MyBatis-Plus配置类中添加乐观锁拦截器

package com.example.config;

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

@Configuration
public class MpConfig {
    @Bean
    public MybatisPlusInterceptor mpInterceptor() {
        // 定义MyBatis-Plus拦截器
        MybatisPlusInterceptor mpInterceptor = new MybatisPlusInterceptor();
        // 添加乐观锁拦截器
        mpInterceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        return mpInterceptor;
    }
}

4.在修改操作中使用乐观锁

    @Test
    void update(){
        User user = new User();
        user.setId(2);
        user.setNumber("123123");
        user.setVersion(2);
        userMapper.updateById(user);
    }

注：一定要设置乐观锁的值，否则效果等效于没有使用乐观锁（没有设置乐观锁值的运行结果如下）