Zookeeper之javaAPI的使用

桃扇骨 2022-10-02 00:53 6阅读 0赞

[2019独角兽企业重金招聘Python工程师标准>>> ][2019_Python_] ![hot3.png][]

## Java程序操作Zookeeper ##

## 1.创建java项目并导入相关jar包 ##

主要jar包在主目录下 ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMwOTg0NTYx_size_16_color_FFFFFF_t_70] 项目需要的相关依赖的jar包在zookeeper的解压文件的lib目录下就有 ![在这里插入图片描述][20190514215001748.png] 将这几个jar包导入项目中 ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMwOTg0NTYx_size_16_color_FFFFFF_t_70 1]

<dependency>
    	<groupId>org.apache.zookeeper</groupId>
    	<artifactId>zookeeper</artifactId>
    	<version>3.4.6</version>
    	<type>pom</type>
    </dependency>
    <dependency>
    	<groupId>com.github.sgroschupf</groupId>
    	<artifactId>zkclient</artifactId>
    	<version>0.1</version>
    </dependency>
    <dependency>
    	<groupId>junit</groupId>
    	<artifactId>junit</artifactId>
    	<version>4.12</version>
    </dependency>

## API简单使用 ##

## 2.1配置Zookeeper对象 ##

// zookeeper的服务器地址,配置conf是用主机名，这里一样
    	private String connectString ="zek00:2181,zek01:2181,zek02:2181";
    	// 连接超时时间
    	private int sessionTimeout = 2000;
    	
    	private ZooKeeper zk = null;
    
    	/**
    	 * 设置zookeeper对象
    	 * @throws IOException 
    	 */
    	@Before
    	public void setZookeeper() throws IOException {
    		
    		zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
    			/**
    			 * 事件触发的回调方法
    			 */
    			@Override
    			public void process(WatchedEvent event) {
    				
    			}
    		});
    		System.out.println("---"+zk);
    	}

## 常用API操作 ##

/**
     * create 方法参数
     *    第一个参数 路径
     *    第二个参数  值  bytes
     *    第三个参数  对节点的访问控制
     *    第四个参数  节点的类型 短暂  永久  序号        
     * @throws KeeperException
     * @throws InterruptedException
     */
    @Test
    public void create() throws KeeperException, InterruptedException {
    	String path = zk.create("/app3", "123".getBytes(), 
    			Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    	System.out.println(path);
    }
    /**
     * 判断节点是否存在
     * @throws InterruptedException 
     * @throws KeeperException 
     */
    @Test
    public void exist() throws KeeperException, InterruptedException{
    	// 设置为 true 会调用 zk中的监听器
    	Stat stat = zk.exists("/app1", true);
    	if(stat!=null){
    		
    		System.out.println("存在。。。。"+stat.getDataLength());
    	}else{
    		System.out.println("不存在。。。");
    	}
    }
    /**
     * 获取子节点
     * @throws InterruptedException 
     * @throws KeeperException 
     */
    @Test
    public void getChilren() throws KeeperException, InterruptedException{
    	List<String> list = zk.getChildren("/", true);
    	for (String s : list) {
    		System.out.println(s);
    	}
    }
    
    /**
     * 获取节点的内容
     * @throws InterruptedException 
     * @throws KeeperException 
     */
    @Test
    public void getData() throws KeeperException, InterruptedException{
    	
    	byte[] b = zk.getData("/app1", false, null );
    	System.out.println(new String(b));
    }
    
    /**
     * 修改节点内容
     * 	  version -1 自动维护
     * @throws InterruptedException 
     * @throws KeeperException 
     */
    @Test
    public void setData() throws KeeperException, InterruptedException{
    	Stat s = zk.setData("/app1", "test".getBytes(), -1);
    }
    /**
     * 删除节点
     *    非空节点删除不掉
     * @throws InterruptedException
     * @throws KeeperException
     */
    @Test
    public void deleteNode() throws InterruptedException, KeeperException{
    	zk.delete("/app1", -1);
    }

## 监听器的使用 ##

@Before
    public static void setUpBeforeClass() throws Exception {
    	zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
    		/**
    		 * 监听器
    		 */
    		@Override
    		public void process(WatchedEvent event) {
    			System.out.println("事件触发...");
    		}
    	});
    }
    
    
    /**
     * 获取子节点
     * getChildren(path,watch?)监听的事件是：节点下的子节点增减变化事件
     * @throws InterruptedException 
     * @throws KeeperException 
     */
    @Test
    public void getChilren() throws KeeperException, InterruptedException{
    	List<String> list = zk.getChildren("/", new Watcher() {
    		
    		@Override
    		public void process(WatchedEvent event) {
    			// TODO Auto-generated method stub
    			System.out.println("监控节点下的子节点被改变..."+event.getPath());
    		}
    	});
    	for (String s : list) {
    		System.out.println(s);
    	}
    	Thread.sleep(Long.MAX_VALUE);
    }
    
    /**
     * 获取节点的内容
     * getData(path,watch?)监听的事件是：节点数据变化事件
     * @throws InterruptedException 
     * @throws KeeperException 
     */
    @Test
    public void getData() throws KeeperException, InterruptedException{
    	
    	byte[] b = zk.getData("/app1", new Watcher() {
    		
    		@Override
    		public void process(WatchedEvent event) {
    			System.out.println("--数据改变了--");
    			
    		}
    	}, null );
    	System.out.println(new String(b));
    	Thread.sleep(Long.MAX_VALUE);
    }

转载于:https://my.oschina.net/u/4116655/blog/3049614

[2019_Python_]: https://my.oschina.net/u/2663968/blog/3061697
[hot3.png]: /images/20220113/d4e5abd7e9824df48e0a38aa09b02092.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMwOTg0NTYx_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/2019051421494643.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMwOTg0NTYx,size_16,color_FFFFFF,t_70
[20190514215001748.png]: https://img-blog.csdnimg.cn/20190514215001748.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMwOTg0NTYx_size_16_color_FFFFFF_t_70 1]: /images/20220113/9d2a19cb84154266881bd896a1e521a0.png