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);
}
}