在Java8之前,代码编译为class文件后,方法参数的类型固定,但是方法名称会丢失,方法名称会变成arg0、arg1….。在Java8开始可以在class文件中保留参数名

public void tet(JoinPoint joinPoint) {
        // 下面两个数组中,参数值和参数名的个数和位置是一一对应的。
        Object[] args = joinPoint.getArgs(); // 参数值
        String[] argNames = ((MethodSignature)joinPoint.getSignature()).getParameterNames(); // 参数名
        // 得到被代理的方法
        Method method = ((MethodSignature) joinPoint.getSignature()).getMethod();
        // 得到被代理的方法上的注解
        Class modelType = method.getAnnotation(RedisCache.class).type();
         // 得到被代理方法的返回值类型
        Class returnType = ((MethodSignature) joinPoint.getSignature()).getReturnType()
}

@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;
		}
	}

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.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
@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;
	}
Logo

华为云1024程序员节送福利,参与活动赢单人4000元礼包,更有热门技术干货免费学习

更多推荐