mybatis-plus 增加乐观锁

安装依赖 

    com.baomidou
    mybatis-plus-boot-starter
    3.5.2

先配置好mybatis-plus开启乐观锁

/**
 * MyBatisPlus配置类
 */
@Configuration
@EnableTransactionManagement
public class MyBatisPlusConfig {

    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        // 配置分页
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        //配置乐观锁
        interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        return interceptor;
    }

在你需要作为版本字段里面加入 @Version 注解

@Version
private Integer version;

写一个aop，进行添加失败重试处理（我是通过自定义注解来进行监听的） 例

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;

@Aspect
@Component
public class RetryOnFailureAspect {
    //    private static final Logger logger = LoggerFactory.getLogger(RetryOnFailureAspect.class);
    private int maxRetries;

    public void setMaxRetries(int maxRetries) {
        this.maxRetries = maxRetries;
    }

    @AfterThrowing(pointcut = "@annotation(com.ruoyi.web.fzzn.common.note.NeedTryAgain)", throwing = "ex")
    public void retryOnFailure(JoinPoint joinPoint, Throwable ex) throws Throwable {
      if (ex instanceof TryAgainException){
            MethodSignature signature = (MethodSignature) joinPoint.getSignature();
            Method method = signature.getMethod();
            NeedTryAgain annotation = method.getAnnotation(NeedTryAgain.class);
            int maxAttempts = annotation.tryTimes();
            int attempts = 0;
            while (attempts < maxAttempts ) {
                attempts++;
                try {
                    method.invoke(joinPoint.getTarget(), joinPoint.getArgs());
                    System.out.println("---------------重试成功-------------------");
                    return;
                } catch (Throwable e) {
                    System.out.println("***********重试次数: "+attempts+"***********");
                }
            }
            throw new RuntimeException("重试失败");
        }
    }
}

自定义注解

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * 重试注解（异常重试，乐观锁更新失败重试）
 */
@Target(ElementType.METHOD) // 作用到方法上
@Retention(RetentionPolicy.RUNTIME)
public @interface NeedTryAgain {

    /**
     * 重试次数
     * @return
     */
    int tryTimes() default 3;

}

自定义一个异常  被乐观锁限制修改或新增失败时抛出这个异常 进行 重试 （可以在aop里面进行判断是否是自己抛出的这个异常）

import org.springframework.http.HttpStatus;

/**
 * 自定义 重试异常
 */
public class TryAgainException extends RuntimeException {

    private Integer status = 500;

    public TryAgainException( String msg) {
        super(msg);
    }

    public TryAgainException(HttpStatus status, String msg) {
        super(msg);
        this.status = status.value();
    }

}

controller示例   实体类和service自己重新定义  

Transactional注解应该加在service的方法上 这里为了方便 就没有进行展示了

 @PostMapping("save")
    @Transactional(noRollbackFor = {TryAgainException.class})
    @NeedTryAgain()
    public R save(@RequestBody ArithmeticEntity arithmeticEntity) {
        ArithmeticEntity byId = arithmeticService.getById(arithmeticEntity.getId());
        ArithmeticEntity byId1 = arithmeticService.getOne(new LambdaQueryWrapper().eq(ArithmeticEntity::getId, arithmeticEntity.getId()));
        byId.setSubscription(byId.getSubscription() + CommonConstants.size);
        byId1.setSubscription(byId1.getSubscription() + CommonConstants.size);
        boolean b1 = arithmeticService.updateById(byId1);
        if (!b1) {
//          回滚
            TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();
            // 保存失败，抛出重试异常
            throw new TryAgainException("乐观锁导致修改失败");
        }
        ArithmeticUserEntity arithmeticUser = new ArithmeticUserEntity();
        BeanUtils.copyProperties(byId, arithmeticUser, "id");
        arithmeticUser.setBelongType(CommonConstants.size);
        arithmeticUserService.save(arithmeticUser);
        return R.ok();
    }