ZooKeeper 原生API

﹏ヽ暗。殇╰゛Y 2023-10-10 12:53 61阅读 0赞

## maven 依赖添加 ##

<dependency>
        <groupId>org.apache.zookeeper</groupId>
        <artifactId>zookeeper</artifactId>
        <version>3.4.6</version>
    </dependency>

## zk客户端与服务器连接 ##

客户端和zk服务端链接是一个异步的过程  
当连接成功后后，客户端会收的一个watch通知

/**
     * @Title: ZKConnectDemo.java
     * @Description: zookeeper 连接demo演示
     */
    public class ZKConnect implements Watcher {
    		
    	final static Logger log = LoggerFactory.getLogger(ZKConnect.class);
    
    	public static final String zkServerPath = "192.168.254.130:2181";
    //	public static final String zkServerPath = "192.168.1.111:2181,192.168.1.111:2182,192.168.1.111:2183";
    	public static final Integer timeout = 5000;
    	
    	public static void main(String[] args) throws Exception {
    		/**
    		 * 客户端和zk服务端链接是一个异步的过程
    		 * 当连接成功后后，客户端会收的一个watch通知
    		 *
    		 * 参数：
    		 * connectString：连接服务器的ip字符串，
    		 * 		比如: "192.168.1.1:2181,192.168.1.2:2181,192.168.1.3:2181"
    		 * 		可以是一个ip，也可以是多个ip，一个ip代表单机，多个ip代表集群
    		 * 		也可以在ip后加路径
    		 * sessionTimeout：超时时间，心跳收不到了，那就超时
    		 * watcher：通知事件，如果有对应的事件触发，则会收到一个通知；如果不需要，那就设置为null
    		 * canBeReadOnly：可读，当这个物理机节点断开后，还是可以读到数据的，只是不能写，
    		 * 					       此时数据被读取到的可能是旧数据，此处建议设置为false，不推荐使用
    		 * sessionId：会话的id
    		 * sessionPasswd：会话密码	当会话丢失后，可以依据 sessionId 和 sessionPasswd 重新获取会话
    		 */
    
    		ZooKeeper zk = new ZooKeeper(zkServerPath, timeout, new ZKConnect());
    		
    		log.warn("客户端开始连接zookeeper服务器...");
    		log.warn("连接状态：{}", zk.getState());
    		new Thread().sleep(2000);
    		log.warn("连接状态：{}", zk.getState());
    	}
    
    	@Override
    	public void process(WatchedEvent event) {
    		log.warn("接受到watch通知：{}", event);
    	}
    }

#### zk会话重连机制 ####

获取到连接zk的会话id和会话密码，我们就可以再次回到会话中

/**
     * 
     * @Title: ZKConnectDemo.java
     * @Description: zookeeper 恢复之前的会话连接demo演示
     */
    public class ZKConnectSessionWatcher implements Watcher {
    	
    	final static Logger log = LoggerFactory.getLogger(ZKConnectSessionWatcher.class);
    
    	public static final String zkServerPath = "192.168.254.130:2181";
    	public static final Integer timeout = 5000;
    	
    	public static void main(String[] args) throws Exception {
    		
    		ZooKeeper zk = new ZooKeeper(zkServerPath, timeout, new ZKConnectSessionWatcher());
    		new Thread().sleep(1000);
    		long sessionId = zk.getSessionId();
    		String ssid = "0x" + Long.toHexString(sessionId);
    		System.out.println(ssid);
    		byte[] sessionPassword = zk.getSessionPasswd();
    		
    		log.warn("客户端开始连接zookeeper服务器...");
    		log.warn("连接状态：{}", zk.getState());
    
    		log.warn("连接状态：{}", zk.getState());
    		
    		new Thread().sleep(200);
    		
    		// 开始会话重连
    		log.warn("开始会话重连...");
    		
    		ZooKeeper zkSession = new ZooKeeper(zkServerPath, 
    											timeout, 
    											new ZKConnectSessionWatcher(), 
    											sessionId, 
    											sessionPassword);
    		log.warn("重新连接状态zkSession：{}", zkSession.getState());
    		new Thread().sleep(1000);
    		log.warn("重新连接状态zkSession：{}", zkSession.getState());
    	}
    	
    	@Override
    	public void process(WatchedEvent event) {
    		log.warn("接受到watch通知：{}", event);
    	}
    }

## java操作zk，节点的创建，删除，设置 ##

/**
     * 
     * @Title: ZKConnectDemo.java
     * @Description: zookeeper 操作demo演示
     */
    public class ZKNodeOperator implements Watcher {
    
    	private ZooKeeper zookeeper = null;
    	
    	public static final String zkServerPath = "192.168.254.130:2181";
    	public static final Integer timeout = 5000;
    	
    	public ZKNodeOperator() {}
    	
    	public ZKNodeOperator(String connectString) {
    		try {
    			zookeeper = new ZooKeeper(connectString, timeout, new ZKNodeOperator());
    		} catch (IOException e) {
    			e.printStackTrace();
    			if (zookeeper != null) {
    				try {
    					zookeeper.close();
    				} catch (InterruptedException e1) {
    					e1.printStackTrace();
    				}
    			}
    		}
    	}
    	
    	/**
    	 * 
    	 * @Title: ZKOperatorDemo.java
    	 * @Description: 创建zk节点
    	 */
    	public void createZKNode(String path, byte[] data, List<ACL> acls) {
    		
    		String result = "";
    		try {
    			/**
    			 * 同步或者异步创建节点，都不支持子节点的递归创建，异步有一个callback函数
    			 * 参数：
    			 * path：创建的路径
    			 * data：存储的数据的byte[]
    			 * acl：控制权限策略
    			 * 			Ids.OPEN_ACL_UNSAFE --> world:anyone:cdrwa
    			 * 			CREATOR_ALL_ACL --> auth:user:password:cdrwa
    			 * createMode：节点类型, 是一个枚举
    			 * 			PERSISTENT：持久节点
    			 * 			PERSISTENT_SEQUENTIAL：持久顺序节点
    			 * 			EPHEMERAL：临时节点
    			 * 			EPHEMERAL_SEQUENTIAL：临时顺序节点
    			 */
    			result = zookeeper.create(path, data, acls, CreateMode.PERSISTENT);
    			
    			//异步创建，CreateCallBack是一个回调函数
    /*			String ctx = "{'create':'success'}";
    			zookeeper.create(path, data, acls, CreateMode.PERSISTENT, new CreateCallBack(), ctx);*/
    			
    			System.out.println("创建节点：\t" + result + "\t成功...");
    			new Thread().sleep(2000);
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    	
    	public static void main(String[] args) throws Exception {
    		ZKNodeOperator zkServer = new ZKNodeOperator(zkServerPath);
    		
    		// 创建zk节点
    		zkServer.createZKNode("/testnode", "testnode".getBytes(), Ids.OPEN_ACL_UNSAFE);
    		
    		/**
    		 * 设置节点数据
    		 * 参数：
    		 * path：节点路径
    		 * data：数据
    		 * version：数据状态
    		 */
    //		Stat status  = zkServer.getZookeeper().setData("/testnode", "xyz".getBytes(), 2);
    //		System.out.println(status.getVersion());
    		
    		/**
    		 * 同步删除数据，没有返回数据
    		 * 参数：
    		 * path：节点路径
    		 * version：数据状态
    		 */
    /*		zkServer.createZKNode("/test-delete-node", "123".getBytes(), Ids.OPEN_ACL_UNSAFE);
    		zkServer.getZookeeper().delete("/test-delete-node", 2);
    		/**
    		 * 异步删除数据，在回调函数里面返回
    		 * 参数：
    		 * path：节点路径
    		 * version：数据状态
    		 */
    		String ctx = "{'delete':'success'}";
    		zkServer.getZookeeper().delete("/test-delete-node", 0, new DeleteCallBack(), ctx);
    		Thread.sleep(2000);*/
    	}
    
    	public ZooKeeper getZookeeper() {
    		return zookeeper;
    	}
    	public void setZookeeper(ZooKeeper zookeeper) {
    		this.zookeeper = zookeeper;
    	}
    
    	@Override
    	public void process(WatchedEvent event) {
    	}
    }

删除回调函数

public class DeleteCallBack implements VoidCallback {
    	@Override
    	public void processResult(int rc, String path, Object ctx) {
    		System.out.println("删除节点" + path);
    		System.out.println((String)ctx);
    	}
    }

## 获取zk节点数据 ##

使用CountDownLatch来监听

public class ZKGetNodeData implements Watcher {
    
    	private ZooKeeper zookeeper = null;
    	
    	public static final String zkServerPath = "192.168.254.130:2181";
    	public static final Integer timeout = 5000;
    	//存放节点数据
    	private static Stat stat = new Stat();
    	
    	public ZKGetNodeData() {}
    	
    	public ZKGetNodeData(String connectString) {
    		try {
    			zookeeper = new ZooKeeper(connectString, timeout, new ZKGetNodeData());
    		} catch (IOException e) {
    			e.printStackTrace();
    			if (zookeeper != null) {
    				try {
    					zookeeper.close();
    				} catch (InterruptedException e1) {
    					e1.printStackTrace();
    				}
    			}
    		}
    	}
    	
    	private static CountDownLatch countDown = new CountDownLatch(1);
    	
    	public static void main(String[] args) throws Exception {
    	
    		ZKGetNodeData zkServer = new ZKGetNodeData(zkServerPath);
    		
    		/**
    		 * 参数：
    		 * path：节点路径
    		 * watch：true或者false，注册一个watch事件
    		 * stat：状态
    		 */
    		byte[] resByte = zkServer.getZookeeper().getData("/bushro", true, stat);
    		String result = new String(resByte);
    		System.out.println("当前值:" + result);
    		countDown.await();
    	}
    	
    	@Override
    	public void process(WatchedEvent event) {
    		try {
    			if(event.getType() == EventType.NodeDataChanged){
    				ZKGetNodeData zkServer = new ZKGetNodeData(zkServerPath);
    				byte[] resByte = zkServer.getZookeeper().getData("/bushro", false, stat);
    				String result = new String(resByte);
    				System.out.println("更改后的值:" + result);
    				System.out.println("版本号变化dversion：" + stat.getVersion());
    				countDown.countDown();
    			} else if(event.getType() == EventType.NodeCreated) {
    				
    			} else if(event.getType() == EventType.NodeChildrenChanged) {
    				
    			} else if(event.getType() == EventType.NodeDeleted) {
    				
    			} 
    		} catch (KeeperException e) { 
    			e.printStackTrace();
    		} catch (InterruptedException e) {
    			e.printStackTrace();
    		}
    	}
    	public ZooKeeper getZookeeper() {
    		return zookeeper;
    	}
    	public void setZookeeper(ZooKeeper zookeeper) {
    		this.zookeeper = zookeeper;
    	}
    }

## 获取zk子节点列表 ##

public class ZKGetChildrenList implements Watcher {
    
    	private ZooKeeper zookeeper = null;
    	
    	public static final String zkServerPath = "192.168.254.130:2181";
    	public static final Integer timeout = 5000;
    	
    	public ZKGetChildrenList() {}
    	
    	public ZKGetChildrenList(String connectString) {
    		try {
    			zookeeper = new ZooKeeper(connectString, timeout, new ZKGetChildrenList());
    		} catch (IOException e) {
    			e.printStackTrace();
    			if (zookeeper != null) {
    				try {
    					zookeeper.close();
    				} catch (InterruptedException e1) {
    					e1.printStackTrace();
    				}
    			}
    		}
    	}
    	
    	private static CountDownLatch countDown = new CountDownLatch(1);
    	
    	public static void main(String[] args) throws Exception {
    	
    		ZKGetChildrenList zkServer = new ZKGetChildrenList(zkServerPath);
    		
    		/**
    		 * 参数：
    		 * path：父节点路径
    		 * watch：true或者false，注册一个watch事件
    		 */
    //		List<String> strChildList = zkServer.getZookeeper().getChildren("/bushro", true);
    //		for (String s : strChildList) {
    //			System.out.println(s);
    //		}
    		
    		// 异步调用
    		String ctx = "{'callback':'ChildrenCallback'}";
    		//回调函数一个是有返回子节点信息（Children2CallBack），一个没有（ChildrenCallBack）
    //		zkServer.getZookeeper().getChildren("/imooc", true, new ChildrenCallBack(), ctx);
    		zkServer.getZookeeper().getChildren("/bushro", true, new Children2CallBack(), ctx);
    		
    		countDown.await();
    	}
    	
    	@Override
    	public void process(WatchedEvent event) {
    		try {
    			if(event.getType()==EventType.NodeChildrenChanged){
    				System.out.println("NodeChildrenChanged");
    				ZKGetChildrenList zkServer = new ZKGetChildrenList(zkServerPath);
    				List<String> strChildList = zkServer.getZookeeper().getChildren(event.getPath(), false);
    				for (String s : strChildList) {
    					System.out.println("子节点： "+s);
    				}
    				countDown.countDown();
    			} else if(event.getType() == EventType.NodeCreated) {
    				System.out.println("NodeCreated");
    			} else if(event.getType() == EventType.NodeDataChanged) {
    				System.out.println("NodeDataChanged");
    			} else if(event.getType() == EventType.NodeDeleted) {
    				System.out.println("NodeDeleted");
    			} 
    		} catch (KeeperException e) {
    			e.printStackTrace();
    		} catch (InterruptedException e) {
    			e.printStackTrace();
    		}
    	}
    
    	public ZooKeeper getZookeeper() {
    		return zookeeper;
    	}
    	public void setZookeeper(ZooKeeper zookeeper) {
    		this.zookeeper = zookeeper;
    	}
    	
    }

回调函数

public class Children2CallBack implements Children2Callback {
    
    	@Override
    	public void processResult(int rc, String path, Object ctx, List<String> children, Stat stat) {
    		for (String s : children) {
    			System.out.println(s);
    		}
    		System.out.println("ChildrenCallback:" + path);
    		System.out.println((String)ctx);	
    		System.out.println("czxid:"+stat.getCzxid());
    		System.out.println("ctime:"+stat.getCtime());
    		System.out.println("mzxid:"+stat.getMzxid());
    		System.out.println("mtime:"+stat.getMtime());
    		System.out.println("pzxid:"+stat.getPzxid());
    		System.out.println("cversion:"+stat.getCversion());
    		System.out.println("version:"+stat.getVersion());
    		System.out.println("ephemeralOwner:"+stat.getEphemeralOwner());
    		System.out.println("numChildren:"+stat.getNumChildren());
    	}
    }

删除子节点后触发的事件

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pob3V6aGl3ZW5nYW5n_size_16_color_FFFFFF_t_70][]

## 判断节点是否存在 ##

public class ZKNodeExist implements Watcher {
    
    	private ZooKeeper zookeeper = null;
    	
    	public static final String zkServerPath = "192.168.254.130:2181";
    	public static final Integer timeout = 5000;
    	
    	public ZKNodeExist() {}
    	
    	public ZKNodeExist(String connectString) {
    		try {
    			zookeeper = new ZooKeeper(connectString, timeout, new ZKNodeExist());
    		} catch (IOException e) {
    			e.printStackTrace();
    			if (zookeeper != null) {
    				try {
    					zookeeper.close();
    				} catch (InterruptedException e1) {
    					e1.printStackTrace();
    				}
    			}
    		}
    	}
    	
    	private static CountDownLatch countDown = new CountDownLatch(1);
    	
    	public static void main(String[] args) throws Exception {
    	
    		ZKNodeExist zkServer = new ZKNodeExist(zkServerPath);
    		
    		/**
    		 * 参数：
    		 * path：节点路径
    		 * watch：watch
    		 */
    		Stat stat = zkServer.getZookeeper().exists("/bushro", true);
    		if (stat != null) {
    			System.out.println("查询的节点版本为dataVersion：" + stat.getVersion());
    		} else {
    			System.out.println("该节点不存在...");
    		}
    		
    		countDown.await();
    	}
    	
    	@Override
    	public void process(WatchedEvent event) {
    		if (event.getType() == EventType.NodeCreated) {
    			System.out.println("节点创建");
    			countDown.countDown();
    		} else if (event.getType() == EventType.NodeDataChanged) {
    			System.out.println("节点数据改变");
    			countDown.countDown();
    		} else if (event.getType() == EventType.NodeDeleted) {
    			System.out.println("节点删除");
    			countDown.countDown();
    		}
    	}
    	
    	public ZooKeeper getZookeeper() {
    		return zookeeper;
    	}
    	public void setZookeeper(ZooKeeper zookeeper) {
    		this.zookeeper = zookeeper;
    	}
    }

## Acl相关操作 ##

public class ZKNodeAcl implements Watcher {
    
    	private ZooKeeper zookeeper = null;
    	
    	public static final String zkServerPath = "192.168.254.130:2181";
    	public static final Integer timeout = 5000;
    	
    	public ZKNodeAcl() {}
    	
    	public ZKNodeAcl(String connectString) {
    		try {
    			zookeeper = new ZooKeeper(connectString, timeout, new ZKNodeAcl());
    		} catch (IOException e) {
    			e.printStackTrace();
    			if (zookeeper != null) {
    				try {
    					zookeeper.close();
    				} catch (InterruptedException e1) {
    					e1.printStackTrace();
    				}
    			}
    		}
    	}
    	
    	public void createZKNode(String path, byte[] data, List<ACL> acls) {
    		
    		String result = "";
    		try {
    			/**
    			 * 同步或者异步创建节点，都不支持子节点的递归创建，异步有一个callback函数
    			 * 参数：
    			 * path：创建的路径
    			 * data：存储的数据的byte[]
    			 * acl：控制权限策略
    			 * 			Ids.OPEN_ACL_UNSAFE --> world:anyone:cdrwa
    			 * 			CREATOR_ALL_ACL --> auth:user:password:cdrwa
    			 * createMode：节点类型, 是一个枚举
    			 * 			PERSISTENT：持久节点
    			 * 			PERSISTENT_SEQUENTIAL：持久顺序节点
    			 * 			EPHEMERAL：临时节点
    			 * 			EPHEMERAL_SEQUENTIAL：临时顺序节点
    			 */
    			result = zookeeper.create(path, data, acls, CreateMode.PERSISTENT);
    			System.out.println("创建节点：\t" + result + "\t成功...");
    		} catch (KeeperException e) {
    			e.printStackTrace();
    		} catch (InterruptedException e) {
    			e.printStackTrace();
    		} 
    	}
    	
    	public static void main(String[] args) throws Exception {
    	
    		ZKNodeAcl zkServer = new ZKNodeAcl(zkServerPath);
    		/**
    		 * ======================  创建node start  ======================  
    		 */
    		//acl 任何人都可以访问
    		zkServer.createZKNode("/aclbushro", "test".getBytes(), Ids.OPEN_ACL_UNSAFE);
    		
    		//(测试1)自定义用户认证访问
    		List<ACL> acls = new ArrayList<ACL>();
    		Id bushro1 = new Id("digest", AclUtils.getDigestUserPwd("bushro1:123456"));
    		Id bushro2 = new Id("digest", AclUtils.getDigestUserPwd("bushro2:123456"));
    		//设置用户以及对应的权限
    		acls.add(new ACL(Perms.ALL, bushro1));
    		acls.add(new ACL(Perms.READ, bushro2));
    		acls.add(new ACL(Perms.DELETE | Perms.CREATE, bushro2));
    		zkServer.createZKNode("/aclbushro/testdigest", "testdigest".getBytes(), acls);
    		
    		//注册过的用户必须通过addAuthInfo才能操作节点，参考命令行 addauth
    		zkServer.getZookeeper().addAuthInfo("digest", "bushro1:123456".getBytes());
    		zkServer.createZKNode("/aclbushro/testdigest/childtest", "childtest".getBytes(), Ids.CREATOR_ALL_ACL);
    		Stat stat = new Stat();
    		byte[] data = zkServer.getZookeeper().getData("/aclbushro/testdigest", false, stat);
    		System.out.println(new String(data));
    		zkServer.getZookeeper().setData("/aclbushro/testdigest", "now".getBytes(), 1);
    
    		//（测试二）ip方式的acl
    		List<ACL> aclsIP = new ArrayList<ACL>();
    		Id ipId1 = new Id("ip", "192.168.1.6");
    		aclsIP.add(new ACL(Perms.ALL, ipId1));
    		zkServer.createZKNode("/aclbushro/iptest6", "iptest".getBytes(), aclsIP);
    
    		//验证ip是否有权限
    		zkServer.getZookeeper().setData("/aclbushro/iptest6", "now".getBytes(), 1);
    		Stat stat = new Stat();
    		byte[] data = zkServer.getZookeeper().getData("/aclbushro/iptest6", false, stat);
    		System.out.println(new String(data));
    		System.out.println(stat.getVersion());
    	}
    
    	public ZooKeeper getZookeeper() {
    		return zookeeper;
    	}
    	public void setZookeeper(ZooKeeper zookeeper) {
    		this.zookeeper = zookeeper;
    	}
    
    	@Override
    	public void process(WatchedEvent event) {
    		
    	}
    }

![20210521123255223.png][]

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[20210521123255223.png]: https://img-blog.csdnimg.cn/20210521123255223.png