MyBatis-Plus应用乐观锁插件

柔光的暖阳◎ 2024-03-22 14:34 58阅读 0赞

**先建一个config包，在建一个类MyBatisPlusConfig**

package com.dzqc.config;
    
    import com.baomidou.mybatisplus.annotation.DbType;
    import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
    import com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor;
    import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    @Configuration
    public class MyBatisPlusConfig {
        @Bean
        public MybatisPlusInterceptor mybatisPlusInterceptor(){
            MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
            //添加分页插件
            mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
            //添加乐观锁插件
            mybatisPlusInterceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
            return mybatisPlusInterceptor;
        }
    }

**在建一个实体类Product**

package com.dzqc.pojo;
    
    import com.baomidou.mybatisplus.annotation.Version;
    import lombok.Data;
    
    @Data
    public class Product {
        private Long id;
        private String name;
        private Double price;
        //标识属性对应的字段作为更新时的版本记录
        @Version
        private Integer version;
    }

**在建一个mapper类，ProductMapper接口**

package com.dzqc.mapper;
    
    import com.baomidou.mybatisplus.core.mapper.BaseMapper;
    import com.dzqc.pojo.Product;
    import org.apache.ibatis.annotations.Mapper;
    import org.springframework.stereotype.Repository;
    
    @Repository
    @Mapper
    public interface ProductMapper extends BaseMapper<Product> {
    }

**在建一个测试类OpLockTest**

package com.dzqc;
    
    import com.dzqc.mapper.ProductMapper;
    import com.dzqc.pojo.Product;
    import org.junit.jupiter.api.Test;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    
    @SpringBootTest
    public class OpLockTest {
        @Autowired
        private ProductMapper productMapper;
        @Test
        public void test1(){
            //A查询商品
            Product productA = productMapper.selectById(1L);
            //B查询商品
            Product productB = productMapper.selectById(1L);
            //A修改价格+50
            productA.setPrice(productA.getPrice()+50);
            //更新数据
            productMapper.updateById(productA);
            //B修改价格-30
            productB.setPrice(productB.getPrice()-30);
            int result = productMapper.updateById(productB);
            if (result==0){//更新失败，重试
                //更新查询id=1的商品信息
                Product product = productMapper.selectById(1L);
                //修改价格
                product.setPrice(product.getPrice()-30);
                //更新数据库
                productMapper.updateById(product);
    
            }
            //最终价格 预计120
            Product productFinal = productMapper.selectById(1L);
            System.out.println("商品最终价格："+productFinal.getPrice());
        }
    }

**测试类结果**

![e0b66bd4348f4c8ba36e94592ff9582c.jpeg][]

[e0b66bd4348f4c8ba36e94592ff9582c.jpeg]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/22/29b292f909e04fc287a3f33ca749ad32.png