(原) 2.2 ZkClient使用
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ZkClient使用
1、jar包引入,演示版本为0.8,非maven项目,可以下载jar包导入到项目中
<dependency> <groupId>com.101tec</groupId> <artifactId>zkclient</artifactId> <version>0.8</version> </dependency>
2、创建Zookeeper连接
示例:ZkClient zc = new ZkClient("192.168.117.128:2181",10000,10000,new SerializableSerializer());
API:ZkClient(java.lang.String zkServers, int sessionTimeout, int connectionTimeout, org.I0Itec.zkclient.serialize.ZkSerializer zkSerializer)
- zkServers:Zookeeper服务器地址
- sessionTimeout:session超时时间
- connectionTimeout:连接超时时间
- zkSerializer:序列化器,ZkClient提供2种
- SerializableSerializer:对象序列化,可转换对象
- BytesPushThroughSerializer:字节数组序列化
3、创建节点
示例:
@Test public void createNode() { createSession(); User user = new User(); user.setId(1l); user.setName("scot"); String path = zc.create("/zkClient_01/02",user, CreateMode.PERSISTENT); System.out.println("path :" + path); }
API:
public java.lang.String create(java.lang.String path, java.lang.Object data, org.apache.zookeeper.CreateMode mode) public java.lang.String create(java.lang.String path, java.lang.Object data, java.util.List<org.apache.zookeeper.data.ACL> acl, org.apache.zookeeper.CreateMode mode)
示例用的为第一种,没有设置访问权限列表(List<org.apache.zookeeper.data.ACL> acl)
- path:创建节点路径。(需要确保父路径存在)
- data:节点数据。设置与获取要注意创建连接时候的序列化器
- Acl:权限列表。详情查看 2.1Zookeeper原始API使用
- mode:节点类型。详情查看 2.1Zookeeper原始API使用
4、节点是否存在
boolean exists(java.lang.String path);
5、获取节点信息
示例:
@Test public void getNode() { createSession(); User user = zc.readData("/zkClient_01"); System.out.println(user.getName()); Stat stat = new Stat(); User user1 = zc.readData("/zkClient_01",stat); System.out.println(user.getName()); System.out.println(stat); }
API:
public <T> T readData(java.lang.String path)public <T> T readData(java.lang.String path, boolean returnNullIfPathNotExists)public <T> T readData(java.lang.String path, org.apache.zookeeper.data.Stat stat)
- path:节点路径。
- returnnullIfPathNotExists:同字面意思,节点不存在返回null
- stat:节点详细信息。传递stat对象到readData方法,方法内部会填充stat数据
6、获取子节点
示例:
@Test public void getChild() { createSession(); String path = "/node_scot"; boolean b = this.exists(path); if(b) { List<String> children =zc.getChildren(path); System.out.println(children.size()); }else { System.out.println("do not have this node"); } }
API:
public java.util.List<java.lang.String> getChildren(java.lang.String path)
7、删除节点
示例:
@Test public void del() { createSession(); String path = "/zkClient_01/01"; if(this.exists(path)) { //zc.delete(path);//删除当前节点,有子节点无法删除 zc.deleteRecursive(path);//删除非子节点 } }
API:
public boolean delete(java.lang.String path) public boolean delete(java.lang.String path, int version) public boolean deleteRecursive(java.lang.String path)
- version:节点的版本。如果版本不符无法删除
8、更新节点信息
示例:
@Test public void writeNode() { createSession(); User user = new User(); user.setId(11l); user.setName("sksujer002"); zc.writeData("/zkClient_01",user); }
9、监控子节点改变(当前节点不存在也可以设置监控)
示例:
@Test public void subscribeChildChange() throws InterruptedException { createSession(); zc.subscribeChildChanges("/zkClient_01",new MyZkChildListener()); Thread.sleep(Integer.MAX_VALUE); } static class MyZkChildListener implements IZkChildListener { @Override public void handleChildChange(String s, List<String> strings) throws Exception { System.out.println("s:"+s); System.out.println("Strings:" + strings); } }
API:
public java.util.List<java.lang.String> subscribeChildChanges(java.lang.String path, org.I0Itec.zkclient.IZkChildListener listener) public interface IZkChildListener { void handleChildChange(java.lang.String parentPath, java.util.List<java.lang.String> currentChilds) throws java.lang.Exception; }
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subscribeChildChanges:注册子节点改变监控
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path:路径
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IZkChildListener listener:子节点监控接口
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IZkChildListener - handChildChange:子节点列表发生改变触发此方法
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parentPath:监控节点路径
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currentChilds:子节点列表
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10、监控节点数据
示例:
@Test public void subscribeDataChange () throws InterruptedException { createSession(); zc.subscribeDataChanges("/zkClient_01",new MyZkDataListener()); Thread.sleep(Integer.MAX_VALUE); } static class MyZkDataListener implements IZkDataListener { @Override public void handleDataChange(String s, Object o) throws Exception { System.out.println("节点信息改变"); System.out.println("s:"+s); System.out.println("o:"+o); } @Override public void handleDataDeleted(String s) throws Exception { System.out.println("节点被删除:"+s); } }
API:
public void subscribeDataChanges(java.lang.String path, org.I0Itec.zkclient.IZkDataListener listener) public interface IZkDataListener { void handleDataChange(java.lang.String dataPath, java.lang.Object object) throws java.lang.Exception; void handleDataDeleted(java.lang.String dataPath) throws java.lang.Exception; }
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subscribeDataChanges:注册节点数据监控
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IZkDataListener listener:数据改变监控接口
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IZkDataListener - handleDataChange:节点数据改变触发此方法
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dataPath:监控节点路径
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object:节点的新数据
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IZkDataListener - handleDataDeleted:节点被删除触发此方法
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dataPath:监控节点路径
下一节:2.3Curator使用
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