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這篇文章給大家分享的是有關(guān)怎么使用Java操作Zookeeper的內(nèi)容。小編覺得挺實(shí)用的,因此分享給大家做個(gè)參考,一起跟隨小編過來看看吧。
1. 簡單,只需理解基本的概念,就可以編寫適合于各種情況的應(yīng)用程序;2. 面向?qū)ο螅?. 分布性,Java是面向網(wǎng)絡(luò)的語言;4. 魯棒性,java提供自動垃圾收集來進(jìn)行內(nèi)存管理,防止程序員在管理內(nèi)存時(shí)容易產(chǎn)生的錯誤。;5. 安全性,用于網(wǎng)絡(luò)、分布環(huán)境下的Java必須防止病毒的入侵。6. 體系結(jié)構(gòu)中立,只要安裝了Java運(yùn)行時(shí)系統(tǒng),就可在任意處理器上運(yùn)行。7. 可移植性,Java可以方便地移植到網(wǎng)絡(luò)上的不同機(jī)器。8.解釋執(zhí)行,Java解釋器直接對Java字節(jié)碼進(jìn)行解釋執(zhí)行。
Maven依賴:
<dependency> <groupId>com.101tec</groupId> <artifactId>zkclient</artifactId> <version>0.11</version> </dependency>
創(chuàng)建節(jié)點(diǎn):
@Test public void testCreateNode() { //建立連接 //zkServers: Zookeeper服務(wù)器IP地址和端口號,如果是集群情況下用逗號分割多個(gè)Zookeeper服務(wù)器地址 //sessionTimeout: 會話超時(shí)時(shí)間 //connectionTimeout: 連接超時(shí)時(shí)間 ZkClient zkClient = new ZkClient("127.0.0.1:2181", 60000, 5000); //創(chuàng)建數(shù)據(jù) Student student = new Student(); student.setName("張三"); student.setAge(18); student.setPhone("1585454xxxx"); //創(chuàng)建持久節(jié)點(diǎn) zkClient.createPersistent("/p_node", student); //創(chuàng)建持久順序節(jié)點(diǎn) zkClient.createPersistentSequential("/ps_node", student); //創(chuàng)建臨時(shí)節(jié)點(diǎn) zkClient.createEphemeral("/e_node", student); //創(chuàng)建臨時(shí)順序節(jié)點(diǎn) zkClient.createEphemeralSequential("/ps_node", student); //關(guān)閉客戶端 //關(guān)閉客戶端的同時(shí),前面創(chuàng)建的臨時(shí)節(jié)點(diǎn)也會被刪除 zkClient.close(); }
讀取節(jié)點(diǎn)數(shù)據(jù):
@Test public void testReadNodeData() { ZkClient zkClient = new ZkClient("127.0.0.1:2181", 60000, 5000); Stat stat = new Stat(); Student student = zkClient.readData("/p_node", stat); System.out.println("節(jié)點(diǎn)狀態(tài)信息:" + JSON.toJSONString(student)); System.out.println("節(jié)點(diǎn)數(shù)據(jù):" + JSON.toJSONString(stat)); zkClient.close(); } //輸出結(jié)果: //節(jié)點(diǎn)狀態(tài)信息:{"age":18,"name":"張三","phone":"1585454xxxx"} //節(jié)點(diǎn)數(shù)據(jù):{"aversion":0,"ctime":1619165355431,"cversion":0,"czxid":165,"dataLength":260,"ephemeralOwner":0,"mtime":1619165355431,"mzxid":165,"numChildren":0,"pzxid":165,"version":0}
刪除節(jié)點(diǎn):
@Test public void testDeleteNode() { ZkClient zkClient = new ZkClient("127.0.0.1:2181", 60000, 5000); //刪除節(jié)點(diǎn),不能刪除帶有子節(jié)點(diǎn)的節(jié)點(diǎn) zkClient.delete("/p_node"); //刪除節(jié)點(diǎn),遞歸刪除所有子孫節(jié)點(diǎn) zkClient.deleteRecursive("/p_node2"); zkClient.close(); }
更新節(jié)點(diǎn)數(shù)據(jù):
@Test public void testWriteNodeData() { ZkClient zkClient = new ZkClient("127.0.0.1:2181", 60000, 5000); //更新節(jié)點(diǎn)數(shù)據(jù) zkClient.writeData("/p_node", "myData1"); //使用CAS更新節(jié)點(diǎn)數(shù)據(jù) //zkClient.writeData("/p_node", "myData2", 1); zkClient.close(); }
獲取子節(jié)點(diǎn)列表:
@Test public void testGetChildNodes() { ZkClient zkClient = new ZkClient("127.0.0.1:2181", 60000, 5000); //獲取子節(jié)點(diǎn)列表 List<String> childList = zkClient.getChildren("/p_node"); childList.stream().forEach(System.out::println); zkClient.close(); }
Java節(jié)點(diǎn)監(jiān)聽都是永久的,觸發(fā)一次后不會被刪除。
監(jiān)聽節(jié)點(diǎn)的子節(jié)點(diǎn)變化:
@Test public void testSubscribeChildChanges() throws IOException { ZkClient zkClient = new ZkClient("127.0.0.1:2181", 60000, 5000); zkClient.subscribeChildChanges("/p_node", new IZkChildListener(){ //子節(jié)點(diǎn)改變時(shí)調(diào)用 @Override public void handleChildChange(String parentPath, List<String> currentChilds) throws Exception { System.out.println(parentPath + "子節(jié)點(diǎn)發(fā)生改變"); System.out.println("當(dāng)前子節(jié)點(diǎn)列表:" + currentChilds); } }); //阻塞客戶端,便于測試 System.in.read(); }
監(jiān)聽節(jié)點(diǎn)數(shù)據(jù)變化:
@Test public void testSubscribeDataChanges() throws IOException { ZkClient zkClient = new ZkClient("127.0.0.1:2181", 60000, 5000); zkClient.subscribeDataChanges("/p_node", new IZkDataListener(){ //節(jié)點(diǎn)數(shù)據(jù)改變時(shí)調(diào)用 @Override public void handleDataChange(String dataPath, Object data) throws Exception { System.out.println(dataPath + "節(jié)點(diǎn)數(shù)據(jù)發(fā)生變化"); System.out.println("修改后的數(shù)據(jù)為:" + data.toString()); } //節(jié)點(diǎn)被刪除時(shí)調(diào)用 @Override public void handleDataDeleted(String dataPath) throws Exception { System.out.println(dataPath + "節(jié)點(diǎn)已被刪除"); } }); //阻塞客戶端,便于測試 System.in.read(); }
監(jiān)聽Zookeeper連接狀態(tài)變化:
@Test public void testSubscribeStateChanges() throws IOException { ZkClient zkClient = new ZkClient("127.0.0.1:2181", 60000, 5000); zkClient.subscribeStateChanges(new IZkStateListener(){ //當(dāng)zookeeper連接狀態(tài)改變時(shí)調(diào)用 @Override public void handleStateChanged(Watcher.Event.KeeperState state) throws Exception { System.out.println("當(dāng)前狀態(tài)" + state); } //在zookeeper會話過期并且創(chuàng)建了一個(gè)新的會話之后調(diào)用 @Override public void handleNewSession() throws Exception { System.out.println("會話過期,已創(chuàng)建新的會話"); } //當(dāng)會話不能重新建立時(shí)調(diào)用 @Override public void handleSessionEstablishmentError(Throwable error) throws Exception { error.printStackTrace(); } }); //阻塞客戶端,便于測試 System.in.read(); }
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