Redis+自定义注解+AOP实现声明式注解缓存查询的示例

方法调用 → 切面拦截 → 生成缓存Key → 查询Redis → 
└ 命中 → 直接返回缓存数据
└ 未命中 → 加锁查DB → 结果写入Redis → 返回数据

package com.mixchains.ytboot.common.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.concurrent.TimeUnit;

/**
 * @author 卫相yang
 * OverSion03
 */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface RedisCache {
    /**
     * Redis键前缀（支持SpEL表达式）
     */
    String key();

    /**
     * 过期时间（默认1天）
     */
    long expire() default 1;

    /**
     * 时间单位（默认天）
     */
    TimeUnit timeUnit() default TimeUnit.DAYS;

    /**
     * 是否缓存空值（防穿透）
     */
    boolean cacheNull() default true;
}

package com.mixchains.ytboot.common.aspect;

import com.alibaba.fastjson.JSON;
import com.mixchains.ytboot.common.annotation.RedisCache;
import io.micrometer.core.instrument.util.StringUtils;
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.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.core.ParameterNameDiscoverer;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;
import java.lang.reflect.Type;

/**
 * @author 卫相yang
 * OverSion03
 */
@Aspect
@Component
@Slf4j
public class RedisCacheAspect {
    @Autowired
    private RedisTemplate<String, String> redisTemplate;

    private final ExpressionParser parser = new SpelExpressionParser();
    private final ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();

    @Around("@annotation(redisCache)")
    public Object around(ProceedingJoinPoint joinPoint, RedisCache redisCache) throws Throwable {
        Method method = ((MethodSignature) joinPoint.getSignature()).getMethod();
        // 解析SpEL表达式生成完整key
        String key = parseKey(redisCache.key(), method, joinPoint.getArgs());
        // 尝试从缓存获取
        String cachedValue = redisTemplate.opsForValue().get(key);
        if (StringUtils.isNotBlank(cachedValue)) {
            Type returnType = ((MethodSignature) joinPoint.getSignature()).getReturnType();
            return JSON.parseObject(cachedValue, returnType);
        }
        // 执行原方法
        Object result = joinPoint.proceed();
        // 处理缓存存储
        if (result != null || redisCache.cacheNull()) {
            String valueToCache = result != null ?
                    JSON.toJSONString(result) :
                    (redisCache.cacheNull() ? "[]" : null);

            if (valueToCache != null) {
                redisTemplate.opsForValue().set(
                        key,
                        valueToCache,
                        redisCache.expire(),
                        redisCache.timeUnit()
                );
            }
        }
        return result;
    }

    private String parseKey(String keyTemplate, Method method, Object[] args) {
        String[] paramNames = parameterNameDiscoverer.getParameterNames(method);
        EvaluationContext context = new StandardEvaluationContext();
        if (paramNames != null) {
            for (int i = 0; i < paramNames.length; i++) {
                context.setVariable(paramNames[i], args[i]);
            }
        }
        return parser.parseExpression(keyTemplate).getValue(context, String.class);
    }
}

 @RedisCache(
            key = "'category:homeSecond:' + #categoryType",  //缓存的Key + 动态参数
            expire = 1, //过期时间
            timeUnit = TimeUnit.DAYS // 时间单位
    )
    @Override
    public ReturnVO<List<GoodsCategory>> listHomeSecondGoodsCategory(Integer level, Integer categoryType) {
        // 数据库查询
        List<GoodsCategory> dbList = goodsCategoryMapper.selectList(
                new LambdaQueryWrapper<GoodsCategory>()
                        .eq(GoodsCategory::getCategoryLevel, level)
                        .eq(GoodsCategory::getCategoryType, categoryType)
                        .eq(GoodsCategory::getIsHomePage, 1)
                        .orderByDesc(GoodsCategory::getHomeSort)
        );
        // 设置父级UUID（可优化为批量查询）
        List<Long> parentIds = dbList.stream().map(GoodsCategory::getParentId).distinct().collect(Collectors.toList());
        Map<Long, String> parentMap = goodsCategoryMapper.selectBatchIds(parentIds)
                .stream()
                .collect(Collectors.toMap(GoodsCategory::getId, GoodsCategory::getUuid));

        dbList.forEach(item -> item.setParentUuid(parentMap.get(item.getParentId())));
        return ReturnVO.ok("列出首页二级分类", dbList);
    }