Dubbo动态负载均衡（socket环境实现）

消费者 去注册中心获取信息 然后缓存到本地 如果有生产者某个服务宕机了  会通过通知的方式告知 （订阅的方式）

微服务rpc远程调用框架中，服务的负载均衡都是采用本地负载均衡的，Spring Cloud  使用的ribbon（本地负载均衡）

如果使用Nginx，那么获取到服务信息后，请求要交给Nginx，再由Nginx进行转发实现负载均衡

本地负载均衡：本地服务从注册中心上获取服务信息列表（缓存在JVM），然后在本地使用rpc远程调用技术，比如Netty、Netty。本地负载均衡更容易实时刷新新数据。

本地效率更高呀

实现如下架构：

在玩的时候注意 不要加端口号

完整路径：/ 一定要加

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>com.toov5.SocketForDubbo</groupId>
  <artifactId>com.toov5.SocketForDubbo</artifactId>
  <version>0.0.1-SNAPSHOT</version>
    <dependencies>
    <dependency>
        <groupId>com.101tec</groupId>
        <artifactId>zkclient</artifactId>
        <version>0.8</version>
    </dependency>
</dependencies>
</project>

　服务器端

package com.toov5.SocketForDubboServer;

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 = 8080; // socket 服务启动后的所使用的 端口号
    private static String parentService = "/service";
    private static ZkClient zkClient = new ZkClient("192.168.91.5");

    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) {
        ZkServerScoekt.port = port;
    }

    // 注册服务
    public static void regServer() {
        // 先创建父节点 判断
        if (!zkClient.exists(parentService)) {
            // 创建父 节点
            zkClient.createPersistent(parentService); // 创建父节点（持久化）

        } //存在就不用管了
        // 创建子节点
        String serverKey = parentService + "/server_" + port; // 约定了个规范
        if (!zkClient.exists(serverKey)) {
            zkClient.createEphemeral(serverKey, "127.0.0.1:" + port); // 临时的 上面的删除是必须的 删除一遍 在创建 保持最新的 本地获取到 进行负载均衡
        } else {
            zkClient.delete(serverKey);
        }
    }

    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) {

            }
        }
    }

}

package com.toov5.SocketForDubboServer;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class ServerHandler implements Runnable {
    private Socket socket;

    public ServerHandler(Socket socket) {
        this.socket = socket;
    }

    public void run() {
        BufferedReader in = null;
        PrintWriter out = null;
        try {
            in = new BufferedReader(new InputStreamReader(this.socket.getInputStream()));
            out = new PrintWriter(this.socket.getOutputStream(), true);
            String body = null;
            while (true) {
                body = in.readLine();
                if (body == null)
                    break;
                System.out.println("Receive : " + body);
                out.println("Hello, " + body);
            }

        } catch (Exception e) {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
            if (out != null) {
                out.close();
            }
            if (this.socket != null) {
                try {
                    this.socket.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
                this.socket = null;
            }
        }
    }
}

客户端

package com.toov5.SocketForDubboClient;

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 javax.mail.Address;

import org.I0Itec.zkclient.IZkChildListener;
import org.I0Itec.zkclient.ZkClient;
import org.apache.zookeeper.data.Stat;
import org.jboss.netty.channel.StaticChannelPipeline;
import org.jboss.netty.util.internal.SystemPropertyUtil;
import org.omg.CORBA.PUBLIC_MEMBER;
import org.w3c.dom.ls.LSInput;

public class ZkServerClient {
    public static List<String> listServer = new ArrayList<String>();
    private static ZkClient zkClient = new ZkClient("192.168.91.5");
    private static String parentService = "/service";

    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() {
        // 读取所有节点 信息
    List<String> children = zkClient.getChildren(parentService);
    getChildren(zkClient, children);
    zkClient.subscribeChildChanges(parentService, new IZkChildListener() {
        public void handleChildChange(String parentPath, List<String> currentChilds) throws Exception {
            System.out.println("注册中心服务列表信息有变化");
            getChildren(zkClient, currentChilds);//如果监听到有变化了 就要重新读取哦
        }
    });    

    }

 public static    void getChildren(ZkClient zkClient, List<String> children) {
     listServer.clear();
    for (String ch : children) {
        String serverAddr = zkClient.readData(parentService + "/" + ch); // 拿到服务地址
        listServer.add(serverAddr);
    }
    System.out.println("服务接口地址"+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() {
        int index = reqCount % listServer.size();
        String address = listServer.get(index);
        System.out.println("客户端请求服务器" + address);
        reqCount++;
        return address;
    }

    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();
                }
            }
        }
    }
}

客户端去获取下面的 地址信息 就好办了：

运行结果

动态的哦