spring整合redis缓存，以注解(@Cacheable、@CachePut、@CacheEvict)形式使用

maven项目中在pom.xml中依赖2个jar包，其他的spring的jar包省略：

<dependency>
   <groupId>redis.clients</groupId>
   <artifactId>jedis</artifactId>
   <version>2.8.1</version>
</dependency>
<dependency>
   <groupId>org.springframework.data</groupId>
   <artifactId>spring-data-redis</artifactId>
   <version>1.7.2.RELEASE</version>
</dependency>

spring-redis.xml中的内容：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:cache="http://www.springframework.org/schema/cache"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context-4.2.xsd
                        http://www.springframework.org/schema/mvc
                        http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd
                        http://www.springframework.org/schema/cache
                        http://www.springframework.org/schema/cache/spring-cache-4.2.xsd"> 

    <context:property-placeholder location="classpath:redis-config.properties" />  

    <!-- 启用缓存注解功能，这个是必须的，否则注解不会生效，另外，该注解一定要声明在spring主配置文件中才会生效 -->
    <cache:annotation-driven cache-manager="cacheManager" />  

     <!-- redis 相关配置 -->
     <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
         <property name="maxIdle" value="${redis.maxIdle}" />
         <property name="maxWaitMillis" value="${redis.maxWait}" />
         <property name="testOnBorrow" value="${redis.testOnBorrow}" />
     </bean>  

     <bean id="JedisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
       p:host-name="${redis.host}" p:port="${redis.port}" p:password="${redis.pass}" p:pool-config-ref="poolConfig"/>  

     <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
         <property name="connectionFactory" ref="JedisConnectionFactory" />
     </bean>  

     <!-- spring自己的缓存管理器，这里定义了缓存位置名称 ，即注解中的value -->
     <bean id="cacheManager" class="org.springframework.cache.support.SimpleCacheManager">
         <property name="caches">
            <set>
                <!-- 这里可以配置多个redis -->
                <!-- <bean class="com.cn.util.RedisCache">
                     <property name="redisTemplate" ref="redisTemplate" />
                     <property name="name" value="default"/>
                </bean> -->
                <bean class="com.cn.util.RedisCache">
                     <property name="redisTemplate" ref="redisTemplate" />
                     <property name="name" value="common"/>
                     <!-- common名称要在类或方法的注解中使用 -->
                </bean>
            </set>
         </property>
     </bean>  

</beans>  

redis-config.properties中的内容：

# Redis settings
# server IP
redis.host=127.0.0.1
# server port
redis.port=6379
# server pass
redis.pass=
# use dbIndex
redis.database=0
# 控制一个pool最多有多少个状态为idle(空闲的)的jedis实例
redis.maxIdle=300
# 表示当borrow(引入)一个jedis实例时，最大的等待时间，如果超过等待时间(毫秒)，则直接抛出JedisConnectionException；
redis.maxWait=3000
# 在borrow一个jedis实例时，是否提前进行validate操作；如果为true，则得到的jedis实例均是可用的
redis.testOnBorrow=true

com.cn.util.RedisCache类中的内容：

package com.cn.util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

import org.springframework.cache.Cache;
import org.springframework.cache.support.SimpleValueWrapper;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;

public class RedisCache implements Cache{

    private RedisTemplate<String, Object> redisTemplate;
    private String name;
    public RedisTemplate<String, Object> getRedisTemplate() {
        return redisTemplate;
    }

    public void setRedisTemplate(RedisTemplate<String, Object> redisTemplate) {
        this.redisTemplate = redisTemplate;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String getName() {
       // TODO Auto-generated method stub
        return this.name;
    }

    @Override
    public Object getNativeCache() {
      // TODO Auto-generated method stub
        return this.redisTemplate;
    }

    @Override
    public ValueWrapper get(Object key) {
      // TODO Auto-generated method stub
      System.out.println("get key");
      final String keyf =  key.toString();
      Object object = null;
      object = redisTemplate.execute(new RedisCallback<Object>() {
      public Object doInRedis(RedisConnection connection)
                  throws DataAccessException {
          byte[] key = keyf.getBytes();
          byte[] value = connection.get(key);
          if (value == null) {
             return null;
            }
          return toObject(value);
          }
       });
        return (object != null ? new SimpleValueWrapper(object) : null);
      }

     @Override
     public void put(Object key, Object value) {
       // TODO Auto-generated method stub
       System.out.println("put key");
       final String keyf = key.toString();
       final Object valuef = value;
       final long liveTime = 86400;
       redisTemplate.execute(new RedisCallback<Long>() {
           public Long doInRedis(RedisConnection connection)
                   throws DataAccessException {
                byte[] keyb = keyf.getBytes();
                byte[] valueb = toByteArray(valuef);
                connection.set(keyb, valueb);
                if (liveTime > 0) {
                    connection.expire(keyb, liveTime);
                 }
                return 1L;
             }
         });
      }

      private byte[] toByteArray(Object obj) {
         byte[] bytes = null;
         ByteArrayOutputStream bos = new ByteArrayOutputStream();
         try {
           ObjectOutputStream oos = new ObjectOutputStream(bos);
           oos.writeObject(obj);
           oos.flush();
           bytes = bos.toByteArray();
           oos.close();
           bos.close();
          }catch (IOException ex) {
               ex.printStackTrace();
          }
          return bytes;
        }  

       private Object toObject(byte[] bytes) {
         Object obj = null;
           try {
               ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
               ObjectInputStream ois = new ObjectInputStream(bis);
               obj = ois.readObject();
               ois.close();
               bis.close();
           } catch (IOException ex) {
               ex.printStackTrace();
            } catch (ClassNotFoundException ex) {
               ex.printStackTrace();
            }
            return obj;
        }

       @Override
       public void evict(Object key) {
         // TODO Auto-generated method stub
         System.out.println("del key");
         final String keyf = key.toString();
         redisTemplate.execute(new RedisCallback<Long>() {
         public Long doInRedis(RedisConnection connection)
                   throws DataAccessException {
             return connection.del(keyf.getBytes());
            }
          });
        }

        @Override
        public void clear() {
           // TODO Auto-generated method stub
            System.out.println("clear key");
           redisTemplate.execute(new RedisCallback<String>() {
                public String doInRedis(RedisConnection connection)
                        throws DataAccessException {
                  connection.flushDb();
                    return "ok";
               }
           });
        }

        @Override
        public <T> T get(Object key, Class<T> type) {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public ValueWrapper putIfAbsent(Object key, Object value) {
            // TODO Auto-generated method stub
            return null;
        }

}

到了这一步，大部分人会想在web.xml的启动配置文件地方(context-param)加入了spring-redis.xml,让项目启动时加载这个配置文件吧，但是这样启动后注解不生效。

正确的做法是：web.xml中配置了servlet控制器：

<servlet>
    <servlet-name>SpringMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>/WEB-INF/spring-mvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
    <async-supported>true</async-supported>
  </servlet>

在DispatcherServlet的初始化过程中，框架会在web应用的 WEB-INF文件夹下寻找名为spring-mvc.xml的配置文件，如果不指定的话，默认是applicationContext.xml

只需要在spring-mvc.xml文件中引入spring-redis配置文件即可，正如spring-redis.xml中的启用注解说的：<cache:annotation-driven cache-manager="cacheManager" />注解一定要声明在spring主配置文件中才会生效。

spring-mvc.xml内容，省略了spring与spring MVC整合的那部分：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context-4.2.xsd
                        http://www.springframework.org/schema/mvc
                        http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd">
    <!-- 自动扫描该包，使SpringMVC认为包下用了@controller注解的类是控制器 -->
    <context:component-scan base-package="com.cn" />  

    <!-- 引入同文件夹下的redis属性配置文件 -->
    <import resource="spring-redis.xml"/>

</beans>

在service的实现类中：

@Service
public class UserServiceImpl implements UserService{

    @Autowired
    private UserBo userBo;

    @Cacheable(value="common",key="'id_'+#id")
    public User selectByPrimaryKey(Integer id) {
        return userBo.selectByPrimaryKey(id);
    }

    @CachePut(value="common",key="#user.getUserName()")
    public void insertSelective(User user) {
        userBo.insertSelective(user);
    }

    @CacheEvict(value="common",key="'id_'+#id")
    public void deleteByPrimaryKey(Integer id) {
        userBo.deleteByPrimaryKey(id);
    }
}