Zookeeper Java API 实例
Zookeeper Java API 实例Api介绍
表 1 org.apache.zookeeper. ZooKeeper 方法列表
除了以上这些上表中列出的方法之外还有一些重载方法，如都提供了一个回调类的重载方法以及可以设置特定 Watcher 的重载方法，具体的方法可以参考 org.apache.zookeeper. ZooKeeper 类的 API 说明。
英文版： https://zookeeper.apache.org/doc/r3.4.2/api/index.html
实例
public class MyZk implements Watcher {
public void process(WatchedEvent watchedEvent) {
System.out.println("触发了" + watchedEvent.getType() + "事件！");
}
}
package com.mylearn.zookeeper.test;
import IceUtilInternal.StringUtil;
import com.jd.common.util.ArrayUtils;
import org.apache.cxf.common.util.StringUtils;
import org.apache.zookeeper.*;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Stat;
import java.io.IOException;
import java.util.List;
/**
* Created by IntelliJ IDEA.
* User: yingkuohao
* Date: 13-11-26
* Time: 上午8:57
* CopyRight:360buy
* Descrption:
* zk java api测试
* To change this template use File | Settings | File Templates.
*/
public class ZkApi {
private static String server = "192.168.229.79:";
private static String port = "2181";
private static final int SESSION_TIMEOUT = 10000;
private static ZooKeeper zk = null;
public static void main(String args[]) {
ZkApi testzkApi = new ZkApi();
Watcher watcher = new MyZk();
// ZooKeeper zk =testzkApi.init(server + port, ClientBase.CONNECTION_TIMEOUT); //创建zk对象
zk = testzkApi.init(server + port, SESSION_TIMEOUT, watcher); //创建zk对象
String parentPath = "/testParentPath"; //节点路径 ,the path for the node
String testParentData = "testParentData"; //节点初始化数据，the initial data for the node
List<ACL> aclList = ZooDefs.Ids.OPEN_ACL_UNSAFE; //节点的权限 the acl for the node
// CreateMode createMode = CreateMode.EPHEMERAL;//临时节点，一旦创建这个节点的客户端与服务端端口session超时，这种节点会被自动删除。
CreateMode createMode = CreateMode.PERSISTENT;//持久节点，这个目录节点存储的数据不会丢失。
try {
createNod(parentPath, testParentData, aclList, createMode);
String parentData = new String(zk.getData(parentPath, false, null));//读取付父节点内容，getData方法
System.out.println("parentData=" + parentData);
String childPath1 = parentPath + "/testChildPath1";
String childData1 = "testChildData1";
createNod(childPath1, childData1, aclList, createMode);//创建子目录 1
String childDataPop = new String(zk.getData(childPath1, false, null));//读取子节点内容
System.out.println("childData1=" + childDataPop);
String childPath2 = parentPath + "/testChildPath2";
String childData2 = "testChildData2";
createNod(childPath2, childData2, aclList, createMode);//创建子目录2
//创建另一个父节点
String parentPath2 = "/testParentPath2";
String testParentData2 = "testParentData2";
createNod(parentPath2, testParentData2, aclList, createMode);
listNode("/");
listNode(parentPath);
Stat stat = zk.exists(parentPath, false);
List<ACL> rootAcl = zk.getACL(parentPath, stat); //获取某个目录节点的访问权限列表。
System.out.println("节点权限：" + ArrayUtils.join(rootAcl.toArray(), ",")+"节点版本："+stat.getVersion());
zk.setACL(parentPath,ZooDefs.Ids.READ_ACL_UNSAFE,stat.getVersion());
System.out.println("节点权限：" + ArrayUtils.join( zk.getACL(parentPath, stat).toArray(), ","));
deleteNode("/testChildPath");
deleteNode(parentPath); //父目录下有子节点，不能直接删除，会报错： KeeperErrorCode = Directory not empty for /testParentPath
listNode("/");
} catch (KeeperException e) {
e.printStackTrace();//To change body of catch statement use File | Settings | File Templates.
} catch (InterruptedException e) {
e.printStackTrace();//To change body of catch statement use File | Settings | File Templates.
}
}
/**
* 删除节点
* @param path
* @throws KeeperException
* @throws InterruptedException
*/
private static void deleteNode(String path) throws KeeperException, InterruptedException {
Stat stat = zk.exists(path, true);
if (stat != null) {
zk.delete(path, -1);//-1可以匹配任何版本，也就删除了这个目录节点所有数据,
System.out.println("删除" + path + "节点成功");
listNode(path);
} else {
System.out.println(path + "节点不存在");
}
}
/**
* 打印节点信息
* @param path
* @throws KeeperException
* @throws InterruptedException
*/
private static void listNode(String path) throws KeeperException, InterruptedException {
List<String> nodeList = zk.getChildren(path, false); //获取孩子节点
System.out.println(path + "路径下的节点" + ArrayUtils.join(nodeList.toArray(), ","));
}
/**
* 创建节点
*
* @param nodePath 节点路径
* @param nodeData 节点初始化数据
* @param aclList 权限列表
* @param createMode 节点类型
* @throws KeeperException
* @throws InterruptedException
*/
private static void createNod(String nodePath, String nodeData, List<ACL> aclList, CreateMode createMode) {
try {
Stat stat = zk.exists(nodePath, true);
if (stat != null) {
//如两次执行 EPHEMERAL节点，就不会执行这段代码，因为每次都会清除；而 PERSISTENT节点，创建一次后就会一直存在，除非手动删除
System.out.println("节点" + nodePath + "已存在！");
} else {
zk.create(nodePath, nodeData.getBytes(), aclList, createMode);//创建节点 ,create方法
}
} catch (KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
/**
* 初始化zk
* @param path
* @param timeOut
* @param watcher
* @return
*/
public ZooKeeper init(String path, int timeOut, Watcher watcher) {
if (zk == null) {
try {
zk = new ZooKeeper(path, timeOut, watcher);
} catch (IOException e) {
e.printStackTrace();//To change body of catch statement use File | Settings | File Templates.
}
}
return zk;
}
}
参考：
https://www.ibm.com/developerworks/cn/opensource/os-cn-zookeeper/
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