發佈方Provider的代碼
package com.zhuyun.release.subscribe;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
public class Provider {
public static void main(String[] args) throws Exception {
Watcher watcher = new Watcher() {
@Override
public void process(WatchedEvent event) {
System.out.println("觸發了" + event.getPath() + "的" + event.getType() + "事件!");
}
};
ZooKeeper zk = new ZooKeeper("192.168.10.203:2181", 20, watcher);
Stat stat = zk.exists("/message", watcher);
if (stat == null) { //假如節點不存在,則先創建節點
zk.create("/message", "hello".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
}
//向該節點發送消息
zk.setData("/message", "hello world".getBytes(), -1);
zk.close();
}
}
訂閱方Consumer的代碼:
package com.zhuyun.release.subscribe;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.ZooKeeper;
public class Consumer implements Watcher{
ZooKeeper zk;
String hostPort;
String znode;
public Consumer(String hostPort,String znode) throws Exception{
this.hostPort = hostPort;
this.znode = znode;
zk = new ZooKeeper(hostPort, 3000, this);
//第一次獲取節點消息,同時添加watcher
System.out.println("消息內容:" + new String(zk.getData(znode, true, null)));
}
@Override
public void process(WatchedEvent event) {
if (event.getType() == EventType.NodeDataChanged) {
try {
//當節點消息變化時,觸發該操作:獲取變化後的消息,同時再添加watcher
System.out.println("你有新的消息:" + new String(zk.getData("/message", true, null)));
} catch (KeeperException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static void main(String[] args) throws Exception {
new Consumer("192.168.10.203:2181","/message");
System.in.read();
}
}
首先啓動訂閱方監聽,再啓動發佈方發佈消息,每次發佈一條消息,訂閱方都能收到該消息,結果如下:
消息內容:我是誰?
你有新的消息:hello
你有新的消息:你好
你有新的消息:hello world