redis订阅发布示例


下面的代码使用redis实现订阅/发布。需要jedis的2.0.0和SLF4J的jar包。

在redis中可以同时订阅多个频道,如果有消息发布是redis会发出通知。jedis中提供了JedisPubSub抽象类来提供发布/订阅的机制,在实际应用中需要实现JedisPubSub类。

 

package practice.redis.pubsub;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPubSub;

/**
* 订阅
* @author 15031483
*
*/
public class Subscriber extends JedisPubSub {

@Override
public void onMessage(String channel, String message) {
System.out.println("onMessage1: channel[" + channel + "], message["
+ message + "]");
}

@Override
public void onPMessage(String pattern, String channel, String message) {
System.out.println("onPMessage2: channel[" + channel + "], message["
+ message + "]");
}

@Override
public void onSubscribe(String channel, int subscribedChannels) {
System.out.println("onSubscribe3: channel[" + channel + "]," +
"subscribedChannels[" + subscribedChannels + "]");
}

@Override
public void onUnsubscribe(String channel, int subscribedChannels) {
System.out.println("onUnsubscribe4: channel[" + channel + "], " +
"subscribedChannels[" + subscribedChannels + "]");
}

@Override
public void onPUnsubscribe(String pattern, int subscribedChannels) {
System.out.println("onPUnsubscribe5: pattern[" + pattern + "]," +
"subscribedChannels[" + subscribedChannels + "]");
}

@Override
public void onPSubscribe(String pattern, int subscribedChannels) {
System.out.println("onPSubscribe6: pattern[" + pattern + "], " +
"subscribedChannels[" + subscribedChannels + "]");
}

public static void main(String[] args) {
Jedis jr = null;
try {
jr = new Jedis("127.0.0.1", 6379, 0);// redis服务地址和端口号
Subscriber sp = new Subscriber();
sp.proceed(jr.getClient(), "news.share");
//sp.proceed(jr.getClient(), "news.share", "news.blog");
// sp.proceedWithPatterns(jr.getClient(), "news.*");
} catch (Exception e) {
e.printStackTrace();
} finally {
if (jr != null) {
jr.disconnect();
}
}
}

}

 

package practice.redis.pubsub;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import redis.clients.jedis.Jedis;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
* 发布
* @author 15031483
*
*/
public class Publisher {

private static final Logger logger = LoggerFactory.getLogger(Publisher.class);

private final Jedis publisherJedis;

private final String channel;

public Publisher(Jedis publisherJedis, String channel) {
this.publisherJedis = publisherJedis;
this.channel = channel;
}

public void start() {
logger.info("Type your message (quit for terminate)");
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
while (true) {
String line = reader.readLine();
if (!"quit".equals(line)) {
publisherJedis.publish(channel, line);
} else {
break;
}
}

} catch (IOException e) {
logger.error("IO failure while reading input, e");
}
}
}

 

package practice.redis.pubsub;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

/**
* 测试reids发布订阅
* @author 15031483
*
*/
public class TestPubSub {
public static final String CHANNEL_NAME = "commonChannel";

private static Logger logger = LoggerFactory.getLogger(TestPubSub.class);

public static void main(String[] args) throws Exception {
JedisPoolConfig poolConfig = new JedisPoolConfig();
JedisPool jedisPool = new JedisPool(poolConfig, "localhost", 6379, 0);
final Jedis subscriberJedis = jedisPool.getResource();
final Subscriber subscriber = new Subscriber();

new Thread(new Runnable() {
@Override
public void run() {
try {
logger.info("Subscribing to \"commonChannel\". This thread will be blocked.");
subscriberJedis.subscribe(subscriber, CHANNEL_NAME);
logger.info("Subscription ended.");
} catch (Exception e) {
logger.error("Subscribing failed.", e);
}
}
}).start();

Jedis publisherJedis = jedisPool.getResource();

new Publisher(publisherJedis, CHANNEL_NAME).start();

subscriber.unsubscribe();
jedisPool.returnResource(subscriberJedis);
jedisPool.returnResource(publisherJedis);
}
}

 

 

  • 要在单独的线程中订阅, 因为subscribe会阻塞当前线程的执行。 你可以使用一个PubSub实例来订阅多个Channel
  • 注意Jedis实例是非线程安全的
  • 当需要创建多个jedis实例时要使用JedisPool类,当使用完jedis对象时要放回JedisPool。

 

 

 

 

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