zk使用通知移除节点

￡神魔★判官ぃ 2022-01-28 13:39 226阅读 0赞

# [zk使用通知移除节点][zk] #

前面：https://www.cnblogs.com/toov5/p/9899238.html 服务发生宕机 咋办？

发个事件通知，告知大家哟，

![1179709-20181103012245151-1996012878.png][]

会有通知事件哦

看项目：

服务端：

package com.toov5.zkDubbo;
    
    import java.io.IOException;
    import java.net.ServerSocket;
    import java.net.Socket;
    
    import org.I0Itec.zkclient.ZkClient;
    
    //##ServerScoekt服务端
    public class ZkServerScoekt implements Runnable {
        private static int port = 18083;  //socket 服务启动后的所使用的 端口号
    
        public static void main(String[] args) throws IOException {
            ZkServerScoekt server = new ZkServerScoekt(port);  //构造函数传入port
            regServer();  //去zk注册
            Thread thread = new Thread(server);
            thread.start();
        }
    
        public ZkServerScoekt(int port) {
            this.port = port;
        }
      //注册服务
        public static void regServer(){
            //1、建立zk连接
        ZkClient zkClient = new ZkClient("192.168.91.5",5000,10000);
            //2.先创建父节点
        String root = "/toov5";
        if (!zkClient.exists(root)) {
            //如果父节点不存，直接创建父节点
            zkClient.createPersistent(root);  //持久节点
        }
           //3、创建子节点
         String nodeName = root+"/service_"+port;      
         String nodeValue="127.0.0.1:"+port;
         if (zkClient.exists(nodeName)) {  //如果存在 直接删除掉
            zkClient.delete(nodeName);
        }
         zkClient.createEphemeral(nodeName,nodeValue); //字节的 临时节点  如果服务宕机了 找不到了
         System.out.println("服务注册成功"+nodeName);
         
        }
        
        
        
        public void run() {
            ServerSocket serverSocket = null;
            try {
                serverSocket = new ServerSocket(port);
                System.out.println("Server start port:" + port);
                Socket socket = null;
                while (true) {
                    socket = serverSocket.accept();
                    new Thread(new ServerHandler(socket)).start();
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    if (serverSocket != null) {
                        serverSocket.close();
                    }
                } catch (Exception e2) {
    
                }
            }
        }
    
    }

客户端

package com.toov5.zkDubbo;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.PrintWriter;
    import java.net.Socket;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.I0Itec.zkclient.IZkChildListener;
    import org.I0Itec.zkclient.ZkClient;
    
    public class ZkServerClient {
        public static List<String> listServer = new ArrayList<String>();
    
        public static void main(String[] args) {
            initServer();
            ZkServerClient     client= new ZkServerClient();
            BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
            while (true) {
                String name;
                try {
                    name = console.readLine();
                    if ("exit".equals(name)) {
                        System.exit(0);
                    }
                    client.send(name);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    
        // 注册所有server 
        public static void initServer() {
            listServer.clear();
    //        listServer.add("127.0.0.1:18080"); //连接服务 放到list中   存放集群地址 做负载均衡用的   
            //建立zk连接
            final ZkClient zkClient = new ZkClient("192.168.91.5",5000,10000);
            //读取父节点信息
           final String root = "/toov5";
            List<String> children=zkClient.getChildren(root);
            for(String pString : children){
                //父+子 =完整的路径
                String path = root+"/"+pString;
                String nodeValue =zkClient.readData(path);
                //把值放到集合中去
                listServer.add(nodeValue);
            }
            //服务发现成功
             System.out.println("服务发现:"+listServer.toString());
             //然后给 serverCount赋值
             serverCount=listServer.size();
             
             //使用zk事件监听，如果服务发生宕机情况，重新读取新的节点
             zkClient.subscribeChildChanges(root, new IZkChildListener() {
                
                public void handleChildChange(String arg0, List<String> children) throws Exception {  //children移除之后 剩下的
                    System.out.println("有服务宕机了，重新读取新的节点信息"+listServer.toString());
                    listServer.clear(); //清除之前的 然后读取最新的
                    for(String pString : children){
                        //父+子 =完整的路径
                        String path = root+"/"+pString;
                        String nodeValue =zkClient.readData(path);
                        //把值放到集合中去
                        listServer.add(nodeValue);
                    }
                    serverCount=children.size();
                    System.out.println("服务发现"+listServer.toString());
                }
            });
                  
        }
        
        
     
      //请求总数
        private static  int  reqCount = 1;
      //服务个数    
        private static int  serverCount = 0; //初始值是0
        
        // 获取当前server信息
        public static String getServer() {
    //        return listServer.get(0);  不能写死  本地负载均衡轮询算法
        String serverName = listServer.get(reqCount%serverCount );
        System.out.println("客户端请求次数："+reqCount+"对应服务器"+serverName);
        reqCount++;
        return serverName;    
        }
        
        public void send(String name) {
    
            String server = ZkServerClient.getServer();
            String[] cfg = server.split(":"); 
    
            Socket socket = null;
            BufferedReader in = null;
            PrintWriter out = null;
            try {
                socket = new Socket(cfg[0], Integer.parseInt(cfg[1]));
                in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                out = new PrintWriter(socket.getOutputStream(), true);
    
                out.println(name);
                while (true) {
                    String resp = in.readLine();
                    if (resp == null)
                        break;
                    else if (resp.length() > 0) {
                        System.out.println("Receive : " + resp);
                        break;
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    try {
                        in.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (socket != null) {
                    try {
                        socket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }

pom:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>zkDobbo</groupId>
      <artifactId>com.toov5.zkDubbo</artifactId>
      <version>0.0.1-SNAPSHOT</version>
       <dependencies>
    		<dependency>
    			<groupId>com.101tec</groupId>
    			<artifactId>zkclient</artifactId>
    			<version>0.8</version>
    		</dependency>
    	</dependencies>
    </project>

启动三个服务端，一个客户端。然后随机关闭一个服务端：

![1179709-20181103015311304-1318415073.png][]

控制台：

![1179709-20181103015325306-859201842.png][]

当有新节点启动时候：

![1179709-20181103015653979-17408572.png][]

![1179709-20181103015726047-1253623625.png][]

![1179709-20181103015433053-545312528.jpg][]

核心部分代码欣赏~~

[zk]: https://www.cnblogs.com/toov5/p/9899310.html
[1179709-20181103012245151-1996012878.png]: /images/20220128/3c8225c6502a4889995918f302561af4.png
[1179709-20181103015311304-1318415073.png]: /images/20220128/d20c1b2ece84455f8cc3d4129c1e61f5.png
[1179709-20181103015325306-859201842.png]: /images/20220128/7cafe6266dfc4e48b11c578499a8fd41.png
[1179709-20181103015653979-17408572.png]: /images/20220128/dbf7efbc24d04540923cb21bb5b11f32.png
[1179709-20181103015726047-1253623625.png]: /images/20220128/ce7958089d5e4fba8d73bd2a63ee57bf.png
[1179709-20181103015433053-545312528.jpg]: /images/20220128/456d7ced26aa49b79f8d27b336981a51.png