CREATE TABLE product
(
    id BIGINT(20) NOT NULL AUTO_INCREMENT COMMENT '主鍵ID',
    name VARCHAR(30) NULL DEFAULT NULL COMMENT '商品名稱',
    price INT(11) DEFAULT 0 COMMENT '價(jià)格',
    version INT(11) DEFAULT 0 COMMENT '樂(lè)觀鎖版本號(hào)',
    PRIMARY KEY (id)
);

INSERT INTO product (id, NAME, price) VALUES (1, '筆記本', 100);

@Data
public class Product {
    private Long id;
    private String name;
    private Integer price;
    private Integer version;
}

public interface ProductMapper extends BaseMapper<Product> {
    
}

@RunWith(SpringRunner.class)
@SpringBootTest
public class ProductVersionTest {
	@Resource
	private ProductMapper productMapper;
	
	@Test
	public void testProductUpdate() {
	
	    //1、小李
	    Product p1 = productMapper.selectById(1L);
	
	    //2、小王
	    Product p2 = productMapper.selectById(1L);
	
	    //3、小李將價(jià)格加了50元，存入了數(shù)據(jù)庫(kù)
	    p1.setPrice(p1.getPrice() + 50);
	    int result1 = productMapper.updateById(p1);
	    System.out.println("小李修改結(jié)果：" + result1);
	
	    //4、小王將商品減了30元，存入了數(shù)據(jù)庫(kù)
	    p2.setPrice(p2.getPrice() - 30);
	    int result2 = productMapper.updateById(p2);
	    System.out.println("小王修改結(jié)果：" + result2);
	
	    //最后的結(jié)果
	    Product p3 = productMapper.selectById(1L);
	    System.out.println("最后的結(jié)果：" + p3.getPrice());
	}
}

SELECT id,`name`,price,`version` FROM product WHERE id=1

UPDATE product SET price=price+50, `version`=`version` + 1 WHERE id=1 AND `version`=1

@Version
private Integer version;

@Configuration
//@MapperScan("com.koo.modules.*.dao")
public class MybatisPlusConfig {

    /**
     * 新的分頁(yè)插件,一緩和二緩遵循mybatis的規(guī)則,需要設(shè)置 MybatisConfiguration#useDeprecatedExecutor = false 避免緩存出現(xiàn)問(wèn)題(該屬性會(huì)在舊插件移除后一同移除)
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        //實(shí)現(xiàn)樂(lè)觀鎖，保證數(shù)據(jù)的準(zhǔn)確性
        interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        return interceptor;
    }

    @Bean
    public ConfigurationCustomizer configurationCustomizer() {
        return configuration -> configuration.setUseDeprecatedExecutor(false);
    }

}

@RunWith(SpringRunner.class)
@SpringBootTest
public class ProductVersionTest {
	@Resource
	private ProductMapper productMapper;
	
	@Test
	public void testProductUpdate() {
	
	    //1、小李
	    Product p1 = productMapper.selectById(1L);
	
	    //2、小王
	    Product p2 = productMapper.selectById(1L);
	
	    //3、小李將價(jià)格加了50元，存入了數(shù)據(jù)庫(kù)
	    p1.setPrice(p1.getPrice() + 50);
	    int result1 = productMapper.updateById(p1);
	    System.out.println("小李修改結(jié)果：" + result1);
	
	    //4、小王將商品減了30元，存入了數(shù)據(jù)庫(kù)
	    p2.setPrice(p2.getPrice() - 30);
	    int result2 = productMapper.updateById(p2);
	    System.out.println("小王修改結(jié)果：" + result2);
	
		if(result2 == 0){//更新失敗，重試
			    System.out.println("小王重試");
			    //重新獲取數(shù)據(jù)
			    p2 = productMapper.selectById(1L);
			    //更新
			    p2.setPrice(p2.getPrice() - 30);
			    productMapper.updateById(p2);
		}
	    //最后的結(jié)果
	    Product p3 = productMapper.selectById(1L);
	    System.out.println("最后的結(jié)果：" + p3.getPrice());
	}
}