## 一、ZKClient的基本使用
public class ZkClientBase {
/** zookeeper地址 */
static final String CONNECT_ADDR = "192.168.1.171:2181,192.168.1.172:2181,192.168.1.173:2181";
/** session超时时间 */
static final int SESSION_OUTTIME = 5000;//ms
public static void main(String[] args) throws Exception {
ZkClient zkc = new ZkClient(new ZkConnection(CONNECT_ADDR), 5000);
//1. create and delete方法
zkc.createEphemeral("/temp");
zkc.createPersistent("/super/c1", true);
Thread.sleep(10000);
zkc.delete("/temp");
zkc.deleteRecursive("/super");
//2. 设置path和data 并且读取子节点和每个节点的内容
zkc.createPersistent("/super", "1234");
zkc.createPersistent("/super/c1", "c1内容");
zkc.createPersistent("/super/c2", "c2内容");
List<String> list = zkc.getChildren("/super");
for(String p : list){
System.out.println(p);
String rp = "/super/" + p;
String data = zkc.readData(rp);
System.out.println("节点为：" + rp + "，内容为: " + data);
}
3. 更新和判断节点是否存在
zkc.writeData("/super/c1", "新内容");
System.out.println(zkc.readData("/super/c1"));
System.out.println(zkc.exists("/super/c1"));
4.递归删除/super内容
zkc.deleteRecursive("/super");
}
}
## 二、zkClient使用 subscribeChildChanges
subscribeChildChanges 方法
参数一：path 路径
参数二、时间了IZKChildListener接口的类（如：实例化IZkChildListener类）
只需要重写其handleChildChange（String parentPath，List<String> currentChilds）
其中parentPath为最新的子节点列表（相对路径）
IZkChildListener事件说明针对于下面三个时间触发
新增子节点、减少子节点、删除节点
### 代码实现
public class ZkClientWatcher1 {
/** zookeeper地址 */
static final String CONNECT_ADDR = "192.168.1.171:2181,192.168.1.172:2181,192.168.1.173:2181";
/** session超时时间 */
static final int SESSION_OUTTIME = 5000;//ms
public static void main(String[] args) throws Exception {
ZkClient zkc = new ZkClient(new ZkConnection(CONNECT_ADDR), 5000);
//对父节点添加监听子节点变化。
zkc.subscribeChildChanges("/super", new IZkChildListener() {
@Override
public void handleChildChange(String parentPath, List<String> currentChilds) throws Exception {
System.out.println("parentPath: " + parentPath);
System.out.println("currentChilds: " + currentChilds);
}
});
Thread.sleep(3000);
zkc.createPersistent("/super");
Thread.sleep(1000);
zkc.createPersistent("/super" + "/" + "c1", "c1内容");
Thread.sleep(1000);
zkc.createPersistent("/super" + "/" + "c2", "c2内容");
Thread.sleep(1000);
zkc.delete("/super/c2");
Thread.sleep(1000);
zkc.deleteRecursive("/super");
Thread.sleep(Integer.MAX_VALUE);
}
}
### 注意
WatchedEvent ： 包含三部分：通知状态、时间类型、节点路径，有了这个路径就可获取到
不监听数据的更新
## 三、subscribeDataChanges
public class ZkClientWatcher2 {
/** zookeeper地址 */
static final String CONNECT_ADDR = "192.168.1.171:2181,192.168.1.172:2181,192.168.1.173:2181";
/** session超时时间 */
static final int SESSION_OUTTIME = 5000;//ms
public static void main(String[] args) throws Exception {
ZkClient zkc = new ZkClient(new ZkConnection(CONNECT_ADDR), 5000);
zkc.createPersistent("/super", "1234");
//对父节点添加监听子节点变化。
zkc.subscribeDataChanges("/super", new IZkDataListener() {
@Override
public void handleDataDeleted(String path) throws Exception {
System.out.println("删除的节点为:" + path);
}
@Override
public void handleDataChange(String path, Object data) throws Exception {
System.out.println("变更的节点为:" + path + ", 变更内容为:" + data);
}
});
Thread.sleep(3000);
zkc.writeData("/super", "456", -1);
Thread.sleep(1000);
zkc.delete("/super");
Thread.sleep(Integer.MAX_VALUE)；
}
}
