手写redis@Cacheable注解支持过期时间设置_谢文峰的博客-CSDN博客

原理解释

友情链接 手写redis @ Cacheable注解参数java对象作为键值

@Cacheable注解作用，将带有该注解方法的返回值存放到redis的的中;

使用方法在方法上使用@Cacheable（键=“测试+＃P0 + P1＃...”）

表示键值为测试+方法第一个参数+方法第二个参数，值为该方法的返回值。

以下源代码表示获取人员列表，Redis的中存放的关键值为'领袖'+ leaderGroupId + UUID + yearDetailId

    @Override
    @Cacheable(key="'leader'+#p0+#p1+#p2",value="leader")
    public List<Leader> listLeaders(String leaderGroupId, String uuid, String yearDetailId) {
        return sysIndexMapper.listLeaders(leaderGroupId, uuid, yearDetailId);
    }

等同于

    @Override
    public List<Leader> listLeaders(String leaderGroupId, String uuid, String yearDetailId) {
        String key = "leader" + leaderGroupId + uuid + yearDetailId;
        // 判断缓存是否存在redis中
        boolean hasKey = redisUtil.hasKey(key);
        if (hasKey) {
                        //如果存在 返还redis中的值
            Object leadersList = redisUtil.get(key);
            return (List<Leader>) leadersList;
        } else {
            List<Leader> leadersQuotaDetailList = sysIndexMapper.listLeaders(leaderGroupId, uuid, yearDetailId);
                        //将查询结果存放在redis中
            redisUtil.set(key, leadersQuotaDetailList);
            return leadersQuotaDetailList;
        }
    }

说白了就是在原方法的前面判断的关键值是否存在的Redis的中，如果存在就取内存中的值，如果不存在就查询数据库，将查询结果存放在Redis的的中。

实现方法

使用代理模式，在方法执行前和执行后可以添加其他处理程序，本文采用springAOP +注解方式。
集成redis，封装Redis工具类
原版本不支持过期时间设置，本文将实现

源代码

缓存配置类RedisConfig

package com.huajie.config;
 
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
 
/**
 * Redis缓存配置类
 */
@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport {
 
    @Value("${spring.redis.host}")
    private String host;
    @Value("${spring.redis.port}")
    private int port;
    @Value("${spring.redis.timeout}")
    private int timeout;
 
    // 自定义缓存key生成策略
    @Bean
    public KeyGenerator keyGenerator() {
        return new KeyGenerator() {
            @Override
            public Object generate(Object target, java.lang.reflect.Method method, Object... params) {
                StringBuffer sb = new StringBuffer();
                sb.append(target.getClass().getName());
                sb.append(method.getName());
                for (Object obj : params) {
                    sb.append(obj.toString());
                }
                return sb.toString();
            }
        };
    }
 
    // 缓存管理器
    @Bean
    public CacheManager cacheManager(@SuppressWarnings("rawtypes") RedisTemplate redisTemplate) {
        RedisCacheManager cacheManager = new RedisCacheManager(redisTemplate);
        // 设置缓存过期时间
        cacheManager.setDefaultExpiration(10000);
        return cacheManager;
    }
 
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<String, Object>();
        template.setConnectionFactory(factory);
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
        // key采用String的序列化方式
        template.setKeySerializer(stringRedisSerializer);
        // hash的key也采用String的序列化方式
        template.setHashKeySerializer(stringRedisSerializer);
        // value序列化方式采用jackson
        template.setValueSerializer(jackson2JsonRedisSerializer);
        // hash的value序列化方式采用jackson
        template.setHashValueSerializer(jackson2JsonRedisSerializer);
        template.afterPropertiesSet();
        return template;
    }
 
    private void setSerializer(StringRedisTemplate template) {
        @SuppressWarnings({ "rawtypes", "unchecked" })
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);
        template.setValueSerializer(jackson2JsonRedisSerializer);
    }
}

Redis的依赖引入，配置文件，工具类RedisUtil，网上几个版本都类似，本文参考以下版本传送门

https://www.cnblogs.com/zeng1994/p/03303c805731afc9aa9c60dbbd32a323.html

准备工作做好之后开始正式编写注解@Cacheable nextkey（）用做二级缓存本文中不会用到

nextKey用法详情> 设计模式（实战） - 责任链模式 <

创建的Java的注解@ExtCacheable

package com.huajie.annotation;
 
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
 
@Target({ ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
public @interface ExtCacheable {
    
    String key() default "";
    
    String nextKey() default "";
 
    int expireTime() default 1800;//30分钟
    
}

SpringAop切面CacheableAspect

package com.huajie.aspect;
 
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
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.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import com.huajie.annotation.ExtCacheable;
import com.huajie.utils.RedisUtil;
 
/**
 * redis缓存处理
 * 不适用与内部方法调用(this.)或者private
 */
@Component
@Aspect
public class CacheableAspect {
    
    @Autowired
    private RedisUtil redisUtil;
 
    @Pointcut("@annotation(com.huajie.annotation.ExtCacheable)")
    public void annotationPointcut() {
    }
 
    @Around("annotationPointcut()")
    public Object doAround(ProceedingJoinPoint joinPoint) throws Throwable {
        // 获得当前访问的class
        Class<?> className = joinPoint.getTarget().getClass();
        // 获得访问的方法名
        String methodName = joinPoint.getSignature().getName();
        // 得到方法的参数的类型
        Class<?>[] argClass = ((MethodSignature) joinPoint.getSignature()).getParameterTypes();
        Object[] args = joinPoint.getArgs();
        String key = "";
        int expireTime = 1800;
        try {
            // 得到访问的方法对象
            Method method = className.getMethod(methodName, argClass);
            method.setAccessible(true);
            // 判断是否存在@ExtCacheable注解
            if (method.isAnnotationPresent(ExtCacheable.class)) {
                ExtCacheable annotation = method.getAnnotation(ExtCacheable.class);
                key = getRedisKey(args,annotation);
                expireTime = getExpireTime(annotation);
            }
        } catch (Exception e) {
            throw new RuntimeException("redis缓存注解参数异常", e);
        }
        // 获取缓存是否存在
        boolean hasKey = redisUtil.hasKey(key);
        if (hasKey) {
            return redisUtil.get(key);
        } else {
                         //执行原方法（java反射执行method获取结果）
            Object res = joinPoint.proceed();
                         //设置缓存
            redisUtil.set(key, res);
                         //设置过期时间
            redisUtil.expire(key, expireTime);
            return res;
        }
    }
    
    private int getExpireTime(ExtCacheable annotation) {
        return annotation.expireTime();
    }
 
    private String getRedisKey(Object[] args,ExtCacheable annotation) {
        String primalKey = annotation.key();
        //获取#p0...集合
        List<String> keyList = getKeyParsList(primalKey);
        for (String keyName : keyList) {
            int keyIndex = Integer.parseInt(keyName.toLowerCase().replace("#p", ""));
            Object parValue = args[keyIndex];
            primalKey = primalKey.replace(keyName, String.valueOf(parValue));
        }
        return primalKey.replace("+","").replace("'","");
    }
 
    // 获取key中#p0中的参数名称
    private static List<String> getKeyParsList(String key) {
        List<String> ListPar = new ArrayList<String>();
        if (key.indexOf("#") >= 0) {
            int plusIndex = key.substring(key.indexOf("#")).indexOf("+");
            int indexNext = 0;
            String parName = "";
            int indexPre = key.indexOf("#");
            if(plusIndex>0){
                indexNext = key.indexOf("#") + key.substring(key.indexOf("#")).indexOf("+");
                parName = key.substring(indexPre, indexNext);
            }else{
                parName = key.substring(indexPre);
            }
            ListPar.add(parName.trim());
            key = key.substring(indexNext + 1);
            if (key.indexOf("#") >= 0) {
                ListPar.addAll(getKeyParsList(key));
            }
        }
        return ListPar;
    }
    
}

业务模块使用方法

    @Override
    @ExtCacheable(key = "Leaders+#p0+#p1+#p2")
    // 手机端获取领导人员列表
    public List<Leader> listLeaders(String leaderGroupId, String uuid, String yearDetailId) {
        List<Leader> leadersQuotaDetailList = sysIndexMapper.listLeaders(leaderGroupId, uuid, yearDetailId);
        return leadersQuotaDetailList;
    }

业务模块过期时间使用方法，5分钟过期

    @Override
    @ExtCacheable(key = "mobileCacheFlag", expireTime = 60 * 5)
    public int cacheFlag() {
        int mobileCacheFlag = 1;
        mobileCacheFlag = sysIndexMapper.cacheFlag();
        return mobileCacheFlag;
    }

Redis的的截图