APP
本篇博客博主为大家带来期待已久的关于ZooKeeper的JavaAPI操作。
目录
一. IDEA环境搭建
1.1 创建一个Maven工程
1.2 添加Porn文件
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.4.10</version>
</dependency>
</dependencies>
1.3 拷贝log4j.properties文件到项目根目录
需要在项目的src/main/resources目录下，新建一个文件，命名为“log4j.properties”，在文件中填入。
log4j.rootLogger=INFO, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n
log4j.appender.logfile=org.apache.log4j.FileAppender
log4j.appender.logfile.File=target/spring.log
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n
前提(测试是否正常连接)
package com.buwenbuhuo.zookeeper;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
import java.util.List;
/**
* @author 卜温不火
* @create 2020-04-27 22:01
* com.buwenbuhuo.zookeeper - the name of the target package where the new class or interface will be created.
* ZooKeeper0427 - the name of the current project.
*/
public class ZkClient {
private ZooKeeper zkCli;
private static final String CONNECT_STRING = "hadoop002:2181,hadoop003:2181,hadoop004:2181";
private static final int SESSION_TIMEOUT = 2000;
// @Before
// public void before() throws IOException {
// zkCli = new ZooKeeper(CONNECT_STRING, SESSION_TIMEOUT, new Watcher() {
// public void process(WatchedEvent watchedEvent) {
//
// }
// });
// }
// 此部分为上部分的简写
@Before
public void before() throws IOException {
zkCli = new ZooKeeper(CONNECT_STRING, SESSION_TIMEOUT, e -> {
System.out.println("默认回调函数");
});
}
@Test
public void ls() throws KeeperException,InterruptedException{
List<String> children = zkCli.getChildren("/",true);
System.out.println("===========================================");
for (String child: children){
System.out.println(child);
}
System.out.println("===========================================");
Thread.sleep(Long.MAX_VALUE);
}
}
2.1 创建ZooKeeper客户端
private static String connectString =
"hadoop002:2181,hadoop003:2181,hadoop004:2181";
private static int sessionTimeout = 2000;
private ZooKeeper zkClient = null;
@Before
public void init() throws Exception {
zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
@Override
public void process(WatchedEvent event) {
// 收到事件通知后的回调函数（用户的业务逻辑）
System.out.println(event.getType() + "--" + event.getPath());
// 再次启动监听
try {
zkClient.getChildren("/", true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
2.2 创建子节点
// 创建子节点
@Test
public void create() throws Exception {
// 参数1：要创建的节点的路径； 参数2：节点数据 ； 参数3：节点权限 ；参数4：节点的类型
String nodeCreated = zkClient.create("/sanguo", "jinlian".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
}
2.4 获取子节点并监听节点变化
// 获取子节点
@Test
public void getChildren() throws Exception {
List<String> children = zkClient.getChildren("/", true);
for (String child : children) {
System.out.println(child);
}
// 延时阻塞
Thread.sleep(Long.MAX_VALUE);
}
2.5 判断Znode是否存在
// 判断znode是否存在
@Test
public void exist() throws Exception {
Stat stat = zkClient.exists("/IDEA", false);
System.out.println(stat == null ? "not exist" : "exist");
}
2.6 基础操作案例
public static void main(String[] args) throws Exception {
// 初始化 ZooKeeper实例(zk地址、会话超时时间，与系统默认一致、watcher)
ZooKeeper zk = new ZooKeeper("hadoop002:2181,hadoop003,hadoop004", 30000, new Watcher() {
@Override
public void process(WatchedEvent event) {
System.out.println("事件类型为：" + event.getType());
System.out.println("事件发生的路径：" + event.getPath());
System.out.println("通知状态为：" +event.getState());
}
});
zk.create("/myGirls", "性感的".getBytes("UTF-8"), Ids.OPEN_ACL_UNSAFE,
CreateMode.PERSISTENT);
zk.close();
2.7 更多实例操作
public static void main(String[] args) throws Exception {
// 初始化 ZooKeeper实例(zk地址、会话超时时间，与系统默认一致、watcher)
ZooKeeper zk = new ZooKeeper("hadoop002:2181,hadoop003,hadoop004", 30000, new Watcher() {
@Override
public void process(WatchedEvent event) {
System.out.println("事件类型为：" + event.getType());
System.out.println("事件发生的路径：" + event.getPath());
System.out.println("通知状态为：" +event.getState());
}
});
// 创建一个目录节点
zk.create("/testRootPath", "testRootData".getBytes(), Ids.OPEN_ACL_UNSAFE,
CreateMode.PERSISTENT);
// 创建一个子目录节点
zk.create("/testRootPath/testChildPathOne", "testChildDataOne".getBytes(),
Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);
System.out.println(new String(zk.getData("/testRootPath",false,null)));
// 取出子目录节点列表
System.out.println(zk.getChildren("/testRootPath",true));
// 修改子目录节点数据
zk.setData("/testRootPath/testChildPathOne","modifyChildDataOne".getBytes(),-1);
System.out.println("目录节点状态：["+zk.exists("/testRootPath",true)+"]");
// 创建另外一个子目录节点
zk.create("/testRootPath/testChildPathTwo", "testChildDataTwo".getBytes(),
Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);
System.out.println(new String(zk.getData("/testRootPath/testChildPathTwo",true,null)));
// 删除子目录节点
zk.delete("/testRootPath/testChildPathTwo",-1);
zk.delete("/testRootPath/testChildPathOne",-1);
// 删除父目录节点
zk.delete("/testRootPath",-1);
zk.close();
}
API操作比较偏向基础，博主在此把注释写了上去。
好了，本次本次的分享就到这里,大家有什么疑惑可以在评论区留言或者私信博主哦。
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本文摘自 ：https://blog.51cto.com/u
