Zookeeper(五)JAVA API
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非常感谢 http://blog.csdn.net/java2000_wl/article/details/8655146
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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- package com.x.zookeeper;
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- import java.io.IOException;
- import java.util.List;
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- 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;
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- public class ZookeeperTest {
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- private static final int SESSION_TIMEOUT = 30000;
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- public static final Logger LOGGER = LoggerFactory.getLogger(ZookeeperTest.class);
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- private Watcher watcher = new Watcher() {
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- public void process(WatchedEvent event) {
- LOGGER.info("process : " + event.getType());
- }
- };
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- private ZooKeeper zooKeeper;
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- @Before
- public void connect() throws IOException {
- zooKeeper = new ZooKeeper("localhost:2181,localhost:2182,localhost:2183", SESSION_TIMEOUT, watcher);
- }
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- @After
- public void close() {
- try {
- zooKeeper.close();
- } catch (InterruptedException e) {
- e.printStackTrace();
- }
- }
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- @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);
- }
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- @Test
- public void testDelete() {
- try {
- zooKeeper.delete("/zk001", -1);
- } catch (Exception e) {
- LOGGER.error(e.getMessage());
- Assert.fail();
- }
- }
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- @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);
- }
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- @Test
- public void testGetDataWatch() {
- String result = null;
- try {
- byte[] bytes = zooKeeper.getData("/zk001", new Watcher() {
- public void process(WatchedEvent event) {
- LOGGER.info("testGetDataWatch watch : {}", event.getType());
- }
- }, null);
- result = new String(bytes);
- } catch (Exception e) {
- LOGGER.error(e.getMessage());
- Assert.fail();
- }
- LOGGER.info("getdata result : {}", result);
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- try {
- zooKeeper.setData("/zk001", "testSetData".getBytes(), -1);
- } catch (Exception e) {
- LOGGER.error(e.getMessage());
- Assert.fail();
- }
- }
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- @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());
- }
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- @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());
- }
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- @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);
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- try {
- zooKeeper.delete("/zk001", -1);
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
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- @Test
- public void testExistsWatch2() {
- Stat stat = null;
- try {
- stat = zooKeeper.exists("/zk002", new Watcher() {
- @Override
- public void process(WatchedEvent event) {
- LOGGER.info("testExistsWatch2 watch : {}", event.getType());
- }
- });
- } catch (Exception e) {
- LOGGER.error(e.getMessage());
- Assert.fail();
- }
- Assert.assertNotNull(stat);
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- try {
- zooKeeper.setData("/zk002", "testExistsWatch2".getBytes(), -1);
- } catch (Exception e) {
- e.printStackTrace();
- }
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- try {
- zooKeeper.delete("/zk002", -1);
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
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- @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);
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- List<String> list = zooKeeper.getChildren("/zk", true);
- for (String node : list) {
- LOGGER.info("node {}", node);
- }
- } catch (Exception e) {
- LOGGER.error(e.getMessage());
- Assert.fail();
- }
- }
- }