Redis是一个key-value的存储系统,提供的key-value类似与Memcached而数据结构又多于memcached,而且性能优异.广泛用于缓存,临时存储等.而我今天
这个例子是使用Redis实现一个订阅/发布系统,而不是如何使用它存储key-value的数据.
Redis是天生支持订阅/发布的,不是我牵强附会拼凑而实现这样的效果,如果真是这样性能没法保证,而且要实现订阅/发布这样的系统是有很多解决方案的.
当然有了发布消息的sendMessage也得有个接收消息的Listener,用于接收订阅到的消息.
代码如:
Spring Schema:
Method属性是配置订阅系统接收消息的方法,默认也是"handleMessage"
topic就是订阅的channel频道,是有发布到java这个channel的消息才会被接收.
测试类:
对于Spring还有传统风格的配置方式,实现的功能和前面一模一样.
Redis是天生支持订阅/发布的,不是我牵强附会拼凑而实现这样的效果,如果真是这样性能没法保证,而且要实现订阅/发布这样的系统是有很多解决方案的.
下载,安装和配置Redis,见: http://my.oschina.net/u/729474/blog/79128 和http://www.php100.com/html/webkaifa/PHP/PHPyingyong/2011/0406/7873.html
Spring一直秉承不发明轮子的,对于很多其他技术都是提供一个模板:Template,如JDBC-JdbcTemplate,JMSTemplate等,Redis他也提供RedisTemplate,有了这个RedisTemplate你可以做任何事,存取key-value,订阅,发布等都通过这个对象实现.
实现一个RedisDAO,接口我不贴了
public class RedisDAOImpl implements RedisDAO {
private RedisTemplate<String, Object> redisTemplate = null;
public RedisDAOImpl() {
}
@Override
public void sendMessage(String channel, Serializable message) {
redisTemplate.convertAndSend(channel, message);
}
public RedisTemplate getRedisTemplate() {
return redisTemplate;
}
public void setRedisTemplate(RedisTemplate redisTemplate) {
this.redisTemplate = redisTemplate;
}
}
可以看到,通过这个 sendMessage方法,我可以把一条可序列化的消息发送到channel频道,订阅者只要订阅了这个channel,他就会接收发布者发布的消息.
当然有了发布消息的sendMessage也得有个接收消息的Listener,用于接收订阅到的消息.
代码如:
public class MessageDelegateListenerImpl implements MessageDelegateListener {
@Override
public void handleMessage(Serializable message) {
//什么都不做,只输出
if(message == null){
System.out.println("null");
} else if(message.getClass().isArray()){
System.out.println(Arrays.toString((Object[])message));
} else if(message instanceof List<?>) {
System.out.println(message);
} else if(message instanceof Map<? , ?>) {
System.out.println(message);
} else {
System.out.println(ToStringBuilder.reflectionToString(message));
}
}
}
好了,有上面的两个类,加上Spring基本上就可以工作了.当然还得启动Redis.
Spring Schema:
<?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:context="http://www.springframework.org/schema/context"
xmlns:redis="http://www.springframework.org/schema/redis"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/redis
http://www.springframework.org/schema/redis/spring-redis-1.0.xsd">
<bean id="redisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
p:hostName="localhost" p:port="6379" p:usePool="true">
</bean>
<!-- redis template definition -->
<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate"
p:connectionFactory-ref="redisConnectionFactory"/>
<bean id="redisDAO" class="net.dredis.dao.impl.RedisDAOImpl">
<property name="redisTemplate" ref="redisTemplate" />
</bean>
<bean id="listener" class="net.dredis.listener.impl.MessageDelegateListenerImpl"/>
<!-- the default ConnectionFactory -->
<bean id="jdkSerializer" class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer" />
<redis:listener-container>
<!-- the method attribute can be skipped as the default method name is "handleMessage" -->
<redis:listener ref="listener" serializer="jdkSerializer" method="handleMessage" topic="java" />
</redis:listener-container>
</beans>
如上面的配置, jdkSerializer是jdk默认的序列化的实现,当然还有很多其他序列化Java对象的方法,这里使用jdk默认实现.
Method属性是配置订阅系统接收消息的方法,默认也是"handleMessage"
topic就是订阅的channel频道,是有发布到java这个channel的消息才会被接收.
测试类:
public static void main(String[] args) {
new ClassPathXmlApplicationContext("pubsubAppContext1.xml");;
while (true) { //这里是一个死循环,目的就是让进程不退出,用于接收发布的消息
try {
System.out.println("current time: " + new Date());
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
OK,启动了订阅系统后,我们就可以发布消息,测试类如:
@Test
public void testPublishMessage() throws Exception {
String msg = "Hello, Redis!";
redisDAO.sendMessage("java", msg); //发布字符串消息
RedisTestBean bean = new RedisTestBean("123456");
bean.setName("Redis");
bean.setOld((byte)2);
bean.setSeliry((short)40);
bean.setManbers(new String[]{"234567", "3456789"});
redisDAO.sendMessage("java", bean); //发布一个普通的javabean消息
Integer[] values = new Integer[]{21341,123123,12323};
redisDAO.sendMessage("java", values); //发布一个数组消息
}
如测试,我连续发布了3条消息,都是不同的数据类型.订阅端输出如:
current time: Fri Oct 26 20:38:31 CST 2012
[21341, 123123, 12323]
java.lang.String@379faa8c[value={H,e,l,l,o,,, ,R,e,d,i,s,!},hash=1345989452]
net.dredis.entity.RedisTestBean@7dee05dc[uid=123456,name=Redis,seliry=40,old=2,manbers={234567,3456789}]
current time: Fri Oct 26 20:38:34 CST 2012
current time: Fri Oct 26 20:38:37 CST 2012
OK他接收到了这3条消息,而且和预期一样.
对于Spring还有传统风格的配置方式,实现的功能和前面一模一样.
<?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:context="http://www.springframework.org/schema/context"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<bean id="jedisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
p:hostName="localhost" p:port="6379" p:usePool="true">
</bean>
<!-- redis template definition -->
<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate"
p:connectionFactory-ref="jedisConnectionFactory"/>
<bean id="redisDAO" class="net.dredis.dao.impl.RedisDAOImpl">
<property name="redisTemplate" ref="redisTemplate" />
</bean>
<bean id="serialization" class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer" />
<bean id="messageDelegateListener" class="net.dredis.listener.impl.MessageDelegateListenerImpl" />
<bean id="messageListener" class="org.springframework.data.redis.listener.adapter.MessageListenerAdapter">
<property name="delegate" ref="messageDelegateListener" />
<property name="serializer" ref="serialization" />
</bean>
<bean id="redisContainer" class="org.springframework.data.redis.listener.RedisMessageListenerContainer">
<property name="connectionFactory" ref="jedisConnectionFactory"/>
<property name="messageListeners">
<!-- map of listeners and their associated topics (channels or/and patterns) -->
<map>
<entry key-ref="messageListener">
<bean class="org.springframework.data.redis.listener.ChannelTopic">
<constructor-arg value="java" />
</bean>
</entry>
</map>
</property>
</bean>
</beans>
来源:oschina
链接:https://my.oschina.net/u/259382/blog/85422