dubbo有自己的服務監聽服務器,incubator-dubbo-ops-develop,github可以下載到,網上也有很多本地部署的例子,就想了下能不能自己監聽dubbo的服務,於是寫了如下代碼。特別注意的是zookeeper的watch機制是一次性觸發,當監聽到該節點的事件被觸發執行了一次watch之後,後面zk該節點的數據需要再次設置watch。以下代碼只是提升對zk節點變化的瞭解,第三方的zk客戶端有例如Curator,它是Netflix公司開源的一個Zookeeper客戶端,與Zookeeper提供的原生客戶端相比,Curator的抽象層次更高,簡化了Zookeeper客戶端的開發量。 還有一個101tec zkclient。curator提供的功能更豐富,zkclient功能相對簡單,參考文檔不如curator。
public class NesttyMain implements Watcher, AsyncCallback.StatCallback {
private static ZooKeeper zooKeeper;
private static Stat stat = new Stat();
private static NesttyMain nestty = new NesttyMain();
public static void main(String[] args) throws InterruptedException, IOException, KeeperException {
zooKeeper = new ZooKeeper("127.0.0.1:2181", 5000, nestty);
Thread.sleep(1000);
nestty.loopWatch("/");
while (true){
}
}
public void loopWatch(String path){
try {
List<String> paths = zooKeeper.getChildren(path,nestty);
if(paths.isEmpty()){
System.out.println(path+" have no children,data are "+new String(zooKeeper.getData(path,true,stat)));
zooKeeper.exists(path,nestty);
return;
}
System.out.println("parent path is: "+path+", children are: "+paths);
for(String childPath: paths){
if (path.equals("/")){
loopWatch("/"+childPath);
}else{
loopWatch(path+"/"+childPath);
}
}
} catch (KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void process(WatchedEvent event) {
if (Event.KeeperState.SyncConnected == event.getState()) {
System.out.println("========event get started========"+new Date());
if(Event.EventType.None == event.getType() && null == event.getPath()){
// 連接時的監聽事件
System.out.println("get connection msg!");
// try {
// zooKeeper.exists("/nestty",nestty);
// } catch (KeeperException e) {
// e.printStackTrace();
// } catch (InterruptedException e) {
// e.printStackTrace();
// }
} else { // 內容變更時的監聽
try {
//監聽當前路徑節點事件,exists只能監聽到當前路徑,子節點的還是需要getchildren
//一次watch處理,只針對一次事件,後續再觸發事件需要再次設置監視
zooKeeper.exists(event.getPath(),nestty);
if(event.getType().equals(Event.EventType.NodeChildrenChanged)){
//監聽子節點變化事件
loopWatch(event.getPath());
}
zooKeeper.getChildren(event.getPath(),nestty);
System.out.println("event path is: "+event.getPath()+", event type is: "+event.getType()+", get msg content data:"
+ new String(zooKeeper.getData(event.getPath(),true,stat)));
System.out.println("get msg stat:czxid=" + stat.getCzxid()
+ ";mzxid=" + stat.getMzxid() + ";version=" + stat.getVersion());
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
public void processResult(int rc, String path, Object ctx, Stat stat) {
System.out.println("xzxzc");
}
}
只需要依賴
org.apache.zookeeper,pom文件如下
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.cqq</groupId>
<artifactId>nestty</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<zookeeper.version>3.4.12</zookeeper.version>
</properties>
<dependencies>
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>${zookeeper.version}</version>
</dependency>
<!--<dependency>-->
<!--<groupId>org.springframework.boot</groupId>-->
<!--<artifactId>spring-boot-starter-web</artifactId>-->
<!--</dependency>-->
</dependencies>
</project>