springBoot自定义防重注解

需求场景

电商的很多场景,比如支付，订单提交，涉及到表单重复提交，会导致许多不必要的生产事故。那么如何优雅的设计一套防重，并做到代码的解耦呢？

设计思路

1.利用spring aop 的自定义注解  2.redis 的分布式锁

具体使用

1.自定义注解

import java.lang.annotation.*;


@Target({ElementType.PARAMETER, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MultiSubmitLimit {
}

2.注解实现

@Aspect
@Component
@Slf4j
public class MultiSubmitLimitHandler {
    /**
     * 锁的默认时间为5秒
     */
    private static final long REPEAT_LOCK_TIME = 5L;
    
    @Pointcut("@annotation(com.xxx.common.annotation.MultiSubmitLimit))")
    public void pointcut() {
    }

     /**
     * 加锁
     * @param joinPoint 请求参数
     */
    @Before("pointcut()")
    public void before(JoinPoint joinPoint) {}

    /**
     * 释放锁
     * @param joinPoint
     * @param result
     */
    @AfterReturning(pointcut = "pointcut()", returning = "result")
    public void afterReturning(JoinPoint joinPoint, Object result) {}
}

定义一个切点

 前置通知

后置通知

3.redis锁防重

加锁

@Before("pointcut()")
    public void before(JoinPoint joinPoint) {
        long start = System.currentTimeMillis();
        Object[] objects = joinPoint.getArgs();
        if (objects.length == 1) {
            String key = String.valueOf(objects[0].hashCode());
            //这里可以加上Token
            if (this.setNx(key, "1", REPEAT_LOCK_TIME)) {
                log.info("check time : {}ms, key:{}", (System.currentTimeMillis() - start), key);
            } else {
                log.error("submitting repeat: {}", joinPoint.toLongString());
                throw new RuntimeException("不要重复提交");
            }
        }
    }

    public Boolean setNx(String key, String value, Long expireTime) {
        return redisTemplate.opsForValue().setIfAbsent(key, value, expireTime, TimeUnit.SECONDS);
    }

释放锁

@AfterReturning(pointcut = "pointcut()", returning = "res")
    public void afterReturning(JoinPoint joinPoint, Object res) {
        Object[] objects = joinPoint.getArgs();
        if (objects.length == 1) {
            String key = String.valueOf(objects[0].hashCode());
            //加上token
            this.delete(key);
            log.info("submitting repeat limit lock released, key:{}", key);
        }
    }

4.使用的时候只要在对应的方法上加上自定义注解@MultiSubmitLimit