Zookeeper（五）JAVA API (转)
org.apache.zookeeper.ZooKeeper类 主要方法列表
方法名称描述String create(final String path, byte data[], List acl, CreateMode createMode) 创建一个znode节点，
参数： 路径、 znode内容，ACL(访问控制列表)、 znode创建类型
void delete(final String path, int version) 删除一个znode节点，
参数： 路径、版本号；如果版本号与znode的版本号不一致，将无法删除，是一种乐观加锁机制；如果将版本号设置为-1，不会去检测版本，直接删除；
Stat exists(final String path, Watcher watcher) 判断某个znode节点是否存在
参数： 路径、Watcher(监视器)；当这个znode节点被改变时，将会触发当前Watcher
Stat exists(String path, boolean watch) 判断某个znode节点是否存在
参数： 路径、并设置是否监控这个目录节点，这里的 watcher 是在创建 ZooKeeper 实例时指定的 watcher
Stat setData(final String path, byte data[], int version) 设置某个znode上的数据
参数： 路径、数据、版本号；如果为-1，跳过版本检查
byte[] getData(final String path, Watcher watcher, Stat stat) 获取某个znode上的数据
参数： 路径、监视器、数据版本等信息
List getChildren(final String path, Watcher watcher) 获取某个节点下的所有子节点
参数： 路径、监视器;该方法有多个重载
znode创建类型(CreateMode)：
PERSISTENT 持久化节点
PERSISTENT_SEQUENTIAL 顺序自动编号持久化节点，这种节点会根据当前已存在的节点数自动加 1
EPHEMERAL 临时节点， 客户端session超时这类节点就会被自动删除
EPHEMERAL_SEQUENTIAL 临时自动编号节点
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[*]/*
[*] * ZookeeperTest.java
[*] */
[*]package com.x.zookeeper;
[*]
[*]import java.io.IOException;
[*]import java.util.List;
[*]
[*]import org.apache.zookeeper.CreateMode;
[*]import org.apache.zookeeper.WatchedEvent;
[*]import org.apache.zookeeper.Watcher;
[*]import org.apache.zookeeper.ZooKeeper;
[*]import org.apache.zookeeper.ZooDefs.Ids;
[*]import org.apache.zookeeper.data.Stat;
[*]import org.junit.After;
[*]import org.junit.Assert;
[*]import org.junit.Before;
[*]import org.junit.Test;
[*]import org.slf4j.Logger;
[*]import org.slf4j.LoggerFactory;
[*]
[*]/**
[*] *
[*] * @author http://blog.iyunv.com/java2000_wl
[*] * @version <b>1.0</b>
[*] */
[*]public class ZookeeperTest {
[*]
[*] private static final int SESSION_TIMEOUT = 30000;
[*]
[*] public static final Logger LOGGER = LoggerFactory.getLogger(ZookeeperTest.class);
[*]
[*] private Watcher watcher =new Watcher() {
[*]
[*] public void process(WatchedEvent event) {
[*] LOGGER.info("process : " + event.getType());
[*] }
[*] };
[*]
[*] private ZooKeeper zooKeeper;
[*]
[*] /**
[*] *连接zookeeper
[*] * <br>------------------------------<br>
[*] * @throws IOException
[*] */
[*] @Before
[*] public void connect() throws IOException {
[*] zooKeeper= new ZooKeeper("localhost:2181,localhost:2182,localhost:2183", SESSION_TIMEOUT, watcher);
[*] }
[*]
[*] /**
[*] *关闭连接
[*] * <br>------------------------------<br>
[*] */
[*] @After
[*] public void close() {
[*] try {
[*] zooKeeper.close();
[*] } catch (InterruptedException e) {
[*] e.printStackTrace();
[*] }
[*] }
[*]
[*] /**
[*] * 创建一个znode
[*] *1.CreateMode 取值
[*] *PERSISTENT：持久化，这个目录节点存储的数据不会丢失
[*] *PERSISTENT_SEQUENTIAL：顺序自动编号的目录节点，这种目录节点会根据当前已近存在的节点数自动加 1，然后返回给客户端已经成功创建的目录节点名；
[*] *EPHEMERAL：临时目录节点，一旦创建这个节点的客户端与服务器端口也就是 session过期超时，这种节点会被自动删除
[*] *EPHEMERAL_SEQUENTIAL：临时自动编号节点
[*] * <br>------------------------------<br>
[*] */
[*] @Test
[*] public void testCreate() {
[*] String result = null;
[*] try {
[*] result = zooKeeper.create("/zk001", "zk001data".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] LOGGER.info("create result : {}", result);
[*] }
[*]
[*] /**
[*] * 删除节点忽略版本
[*] * <br>------------------------------<br>
[*] */
[*] @Test
[*] public void testDelete() {
[*] try {
[*] zooKeeper.delete("/zk001", -1);
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] }
[*]
[*] /**
[*] * 获取数据
[*] * <br>------------------------------<br>
[*] */
[*] @Test
[*] public void testGetData() {
[*] String result = null;
[*] try {
[*] byte[] bytes = zooKeeper.getData("/zk001", null, null);
[*] result = new String(bytes);
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] LOGGER.info("getdata result : {}", result);
[*] }
[*]
[*] /**
[*] * 获取数据设置watch
[*] * <br>------------------------------<br>
[*] */
[*] @Test
[*] public void testGetDataWatch() {
[*] String result = null;
[*] try {
[*] byte[] bytes = zooKeeper.getData("/zk001", new Watcher() {
[*] public void process(WatchedEvent event) {
[*] LOGGER.info("testGetDataWatchwatch : {}", event.getType());
[*] }
[*] }, null);
[*] result = new String(bytes);
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] LOGGER.info("getdata result : {}", result);
[*]
[*] // 触发wacthNodeDataChanged
[*] try {
[*] zooKeeper.setData("/zk001", "testSetData".getBytes(), -1);
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] }
[*]
[*] /**
[*] * 判断节点是否存在
[*] * 设置是否监控这个目录节点，这里的 watcher 是在创建 ZooKeeper实例时指定的 watcher
[*] * <br>------------------------------<br>
[*] */
[*] @Test
[*] public void testExists() {
[*] Stat stat = null;
[*] try {
[*] stat = zooKeeper.exists("/zk001", false);
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] Assert.assertNotNull(stat);
[*] LOGGER.info("exists result : {}", stat.getCzxid());
[*] }
[*]
[*] /**
[*] * 设置对应znode下的数据,-1表示匹配所有版本
[*] * <br>------------------------------<br>
[*] */
[*] @Test
[*] public void testSetData() {
[*] Stat stat = null;
[*] try {
[*] stat = zooKeeper.setData("/zk001", "testSetData".getBytes(), -1);
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] Assert.assertNotNull(stat);
[*] LOGGER.info("exists result : {}", stat.getVersion());
[*] }
[*]
[*] /**
[*] * 判断节点是否存在,
[*] * 设置是否监控这个目录节点，这里的 watcher 是在创建 ZooKeeper实例时指定的 watcher
[*] * <br>------------------------------<br>
[*] */
[*] @Test
[*] public void testExistsWatch1() {
[*] Stat stat = null;
[*] try {
[*] stat = zooKeeper.exists("/zk001", true);
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] Assert.assertNotNull(stat);
[*]
[*] try {
[*] zooKeeper.delete("/zk001", -1);
[*] } catch (Exception e) {
[*] e.printStackTrace();
[*] }
[*] }
[*]
[*] /**
[*] * 判断节点是否存在,
[*] * 设置监控这个目录节点的 Watcher
[*] * <br>------------------------------<br>
[*] */
[*] @Test
[*] public void testExistsWatch2() {
[*] Stat stat = null;
[*] try {
[*] stat = zooKeeper.exists("/zk002", new Watcher() {
[*] @Override
[*] public void process(WatchedEvent event) {
[*] LOGGER.info("testExistsWatch2watch : {}", event.getType());
[*] }
[*] });
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] Assert.assertNotNull(stat);
[*]
[*] // 触发watch 中的process方法 NodeDataChanged
[*] try {
[*] zooKeeper.setData("/zk002", "testExistsWatch2".getBytes(), -1);
[*] } catch (Exception e) {
[*] e.printStackTrace();
[*] }
[*]
[*] // 不会触发watch 只会触发一次
[*] try {
[*] zooKeeper.delete("/zk002", -1);
[*] } catch (Exception e) {
[*] e.printStackTrace();
[*] }
[*] }
[*]
[*] /**
[*] *获取指定节点下的子节点
[*] * <br>------------------------------<br>
[*] */
[*] @Test
[*] public void testGetChild() {
[*] try {
[*] zooKeeper.create("/zk/001", "001".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
[*] zooKeeper.create("/zk/002", "002".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
[*]
[*] List<String> list = zooKeeper.getChildren("/zk", true);
[*] for (String node : list) {
[*] LOGGER.info("node {}", node);
[*] }
[*] } catch (Exception e) {
[*] LOGGER.error(e.getMessage());
[*] Assert.fail();
[*] }
[*] }
[*]}
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