统一缓存处理

为什么要做缓存处理？
内存的访问速度 远远大于 磁盘的访问速度 （1000倍起）

<!--md5加密-->
        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
        </dependency>
<!--redis-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
            <version>2.5.3</version>
        </dependency>

import java.lang.annotation.*;

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Cache {

    long expire() default 1 * 60 * 1000;

    String name() default "";

}

import com.alibaba.fastjson.JSON;
import com.mszlu.blog.vo.Result;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.Signature;
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.core.annotation.AliasFor;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;
import java.time.Duration;

@Aspect
@Component
@Slf4j
public class CacheAspect {

    @Autowired
    private RedisTemplate<String, String> redisTemplate;

    @Pointcut("@annotation(com.mszlu.blog.common.cache.Cache)")
    public void pt(){}

    @Around("pt()")
    public Object around(ProceedingJoinPoint pjp){
        try {
            Signature signature = pjp.getSignature();
            //类名
            String className = pjp.getTarget().getClass().getSimpleName();
            //调用的方法名
            String methodName = signature.getName();


            Class[] parameterTypes = new Class[pjp.getArgs().length];
            Object[] args = pjp.getArgs();
            //参数
            String params = "";
            for(int i=0; i<args.length; i++) {
                if(args[i] != null) {
                    params += JSON.toJSONString(args[i]);
                    parameterTypes[i] = args[i].getClass();
                }else {
                    parameterTypes[i] = null;
                }
            }
            if (StringUtils.isNotEmpty(params)) {
                //加密 以防出现key过长以及字符转义获取不到的情况
                params = DigestUtils.md5Hex(params);
            }
            Method method = pjp.getSignature().getDeclaringType().getMethod(methodName, parameterTypes);
            //获取Cache注解
            Cache annotation = method.getAnnotation(Cache.class);
            //缓存过期时间
            long expire = annotation.expire();
            //缓存名称
            String name = annotation.name();
            //先从redis获取
            String redisKey = name + "::" + className+"::"+methodName+"::"+params;
            String redisValue = redisTemplate.opsForValue().get(redisKey);
            if (StringUtils.isNotEmpty(redisValue)){
                log.info("走了缓存~~~,{},{}",className,methodName);
                return JSON.parseObject(redisValue, Result.class);
            }
            Object proceed = pjp.proceed();
            redisTemplate.opsForValue().set(redisKey,JSON.toJSONString(proceed), Duration.ofMillis(expire));
            log.info("存入缓存~~~ {},{}",className,methodName);
            return proceed;
        } catch (Throwable throwable) {
            throwable.printStackTrace();
        }
        return Result.fail(-999,"系统错误");
    }

}

使用

@PostMapping("hot")
    @Cache(expire = 5 * 60 * 1000,name = "hot_article")
    public Result hotArticle(){
        int limit = 5;
        return articleService.hotArticle(limit);
    }