springboot整合redis+自定义注解+反射+aop实现分布式锁

小鱼儿 2024-02-17 11:43 10阅读 0赞

### **1.定义注解** ###

import java.lang.annotation.*;
    import java.util.concurrent.TimeUnit;
    
    /** @Author: best_liu
     * @Description:
     * @Date: 16:13 2023/9/4
     * @Param 
     * @return 
     **/
    @Retention(RetentionPolicy.RUNTIME)
    @Target({ElementType.METHOD})
    @Documented
    public @interface RedisLock {
        String lockPrefix() default "";
    
        String lockKey() default "";
    
        //是否使用自定义过期时间,false->配置文件获取;true->自己指定过期时间
        boolean expireConfig() default true;
    
        long timeOut() default 30;
    
        TimeUnit timeUnit() default TimeUnit.SECONDS;
    }

### **2.aop+redis** ###

利用redis 的setIfAbsent()方法获取锁

import lombok.extern.slf4j.Slf4j;
    import org.aspectj.lang.ProceedingJoinPoint;
    import org.aspectj.lang.annotation.Around;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Pointcut;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.data.redis.core.RedisTemplate;
    import org.springframework.stereotype.Component;
    
    import java.lang.reflect.Method;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.concurrent.TimeUnit;
    
    /** @Author: best_liu
     * @Description:
     * @Date: 16:13 2023/9/4
     * @Param 
     * @return 
     **/
    @Aspect
    @Component
    @Slf4j
    public class RedisLockAspect {
        private static final Integer Max_RETRY_COUNT = 3;
        private static final String LOCK_PRE_FIX = "lockPreFix";
        private static final String LOCK_KEY = "lockKey";
        private static final String TIME_OUT = "timeOut";
        private static final String EXPIRE_CONFIG = "expireConfig";
    
        @Value("${schedule.expire}")
        private long timeOut;
    
        @Autowired
        private RedisTemplate redisTemplate;
    
        @Pointcut("@annotation(com.mes.dispatch.annotation.redisLock.RedisLock)")
        public void redisLockAspect() {
        }
    
        @Around("redisLockAspect()")
        public void lockAroundAction(ProceedingJoinPoint proceeding) throws Exception {
    
            //获取注解中的参数
            Map<String, Object> annotationArgs = this.getAnnotationArgs(proceeding);
            String lockPrefix = (String) annotationArgs.get(LOCK_PRE_FIX);
            String key = (String) annotationArgs.get(LOCK_KEY);
            long expire = (long) annotationArgs.get(TIME_OUT);
            boolean expireConfig = (boolean) annotationArgs.get(EXPIRE_CONFIG);
            //分布式锁
            boolean lock = false;
            try {
                //如果返回true，说明key不存在，获取到锁
                lock = redisTemplate.opsForValue().setIfAbsent(key, lockPrefix);
                log.info("是否获取到锁:" + lock);
                if (lock) {
                    log.info("获取到锁，开启定时任务！");
                    //设置过期时间
                    if (expireConfig) {
                        redisTemplate.expire(key, expire, TimeUnit.SECONDS);
                    } else {
                        redisTemplate.expire(key, timeOut, TimeUnit.SECONDS);
                    }
    
                    proceeding.proceed();
                } else {
                    log.info("其他系统正在执行此项任务");
                    return;
                }
            } catch (Exception e) {
                e.printStackTrace();
            } catch (Throwable throwable) {
                throw new RuntimeException("分布式锁执行发生异常" + throwable.getMessage(), throwable);
            }
        }
    
        /**
         * 获取锁参数
         *
         * @param proceeding
         * @return
         */
        private Map<String, Object> getAnnotationArgs(ProceedingJoinPoint proceeding) {
            Class target = proceeding.getTarget().getClass();
            Method[] methods = target.getMethods();
            String methodName = proceeding.getSignature().getName();
            for (Method method : methods) {
                if (method.getName().equals(methodName)) {
                    Map<String, Object> result = new HashMap<String, Object>();
                    RedisLock redisLock = method.getAnnotation(RedisLock.class);
                    result.put(LOCK_PRE_FIX, redisLock.lockPrefix());
                    result.put(LOCK_KEY, redisLock.lockKey());
                    result.put(TIME_OUT, redisLock.timeUnit().toSeconds(redisLock.timeOut()));
                    result.put(EXPIRE_CONFIG, redisLock.expireConfig());
                    return result;
                }
            }
            return null;
        }
    
    }

### 3.使用 ###

![52e6dda1b8604599aa73b6f4975a10b3.png][]

[52e6dda1b8604599aa73b6f4975a10b3.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/02/06/96774b1878f244c6a6ccd11ad2bbc9a8.png