目录原理解释实现方法源代码
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
@Overridepublic 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@EnableCachingpublic 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@Beanpublic KeyGenerator keyGenerator() {return new KeyGenerator() {@Overridepublic 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@Beanpublic CacheManager cacheManager(@SuppressWarnings("rawtypes") RedisTemplate redisTemplate) {RedisCacheManager cacheManager = new RedisCacheManager(redisTemplate);// 设置缓存过期时间cacheManager.setDefaultExpiration(10000);return cacheManager;} @Beanpublic 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jacksontemplate.setValueSerializer(jackson2JsonRedisSerializer);// hash的value序列化方式采用jacksontemplate.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.jb51.net/article/233562.htm
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@Aspectpublic class CacheableAspect {@Autowiredprivate 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classClass<?> 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
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
大把大把的时光从指缝间遛走，
