自定义注解解耦reids缓存使用

Posted 2021-11-26 long757747969

package test.cache;


import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.session.SessionProperties;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import redis.RedisUtils;
import redis.clients.jedis.Jedis;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.Lock;

@Aspect
@Component
public class TestCacheAop {

    ConcurrentHashMap<String,String> lock = new ConcurrentHashMap();

    @Autowired
    RedisTemplate redisTemplate;

    @Pointcut(value="execution(public * test*.*.*.*(..))&&@annotation(TestCache)")
    public void cachePointcut() {

    }

    @Around("cachePointcut()")
    public Object around (ProceedingJoinPoint joinPoint) throws NoSuchMethodException {
        //Annotation annotation = joinPoint.getTarget().getClass().getAnnotation(TestCache.class);

        TestCache testCache = ((MethodSignature)joinPoint.getSignature()).getMethod().getAnnotation(TestCache.class);
        if(testCache  == null) {
            return null;
        }

        String key = testCache.value();
        if(key==null) {
            return null;
        }

        MethodSignature methodSignature =(MethodSignature) joinPoint.getSignature();
        Method method = joinPoint.getTarget().getClass().getMethod(methodSignature.getName(),methodSignature.getMethod().getParameterTypes());

        //java编译后的方法参数默认是不会显示参数名称的需要转换
        DefaultParameterNameDiscoverer discoverer = new DefaultParameterNameDiscoverer();
        String[] parameters = discoverer.getParameterNames(method);

        String cacheKey = key;
        for(int i=0;i<parameters.length;i++) {
            if(parameters[i].equals(key)) {
                cacheKey = String.valueOf(joinPoint.getArgs()[i]);
                break;
            }
        }

        Object value = redisTemplate.opsForValue().get(cacheKey);
        if(value!=null) {
            return value;
        }

        //防止缓存雪崩
        String cacheFlag = lock.putIfAbsent(cacheKey,"true");

        Object obj = null;
        if(cacheFlag == null) {
            try {
                obj = joinPoint.proceed();
                redisTemplate.opsForValue().set(cacheKey,obj);
            } catch(Throwable throwable) {
                throwable.printStackTrace();
            }
            return obj;
        }else {
            return "当前系统忙";
        }
    }

}