思路：
使用Zookeeper实现负载均衡原理：服务器端将启动的服务注册到zk注册中心上，采用临时节点。
客户端从zk节点上获取最新服务节点信息，本地使用负载均衡算法，随机分配服务器。
废话不说，直接上代码
pom文件：
<dependencies>
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.4.6</version>
</dependency>
<dependency>
<groupId>com.101tec</groupId>
<artifactId>zkclient</artifactId>
<version>0.8</version>
</dependency>
</dependencies>
ServerHandler.java
package com.infosys;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
//ServerHandler
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;
}
}
}
}
ZkServerClient.java
package com.infosys;
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;
/**
*
* <一句话功能简述>
* <功能详细描述>
*
* @author Jiayoubing
* @version [版本号,2020年3月28日]
* @see [相关类/方法]
* @since [产品/模块版本]
*/
public class ZkServerClient
{
// 服务器列表
public static List<String> listServer = new ArrayList<String>();
public static String parent = "/test";
// 请求次数
private static int reqestCount = 1;
// 服务数量
private static int serverCount = 0;
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();
}
}
}
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();
}
}
}
}
/**
*
* 获取当前server信息
*
* @return[参数说明] @return String[返回类型说明]
* @exception throws
* [违例类型][违例说明]
* @see [类、类#方法、类#成员]
*/
public static String getServer()
{
// 实现负载均衡
String serverName = listServer.get(reqestCount % serverCount);
++reqestCount;
System.out.println(">>>>>>>>>>>>>>本地负载均衡服务为：" + serverName);
return serverName;
}
/**
* 获取zookeeper上面的服务器列表 <一句话功能简述> <功能详细描述>[参数说明]
*
* @return void[返回类型说明]
* @exception throws
* [违例类型][违例说明]
* @see [类、类#方法、类#成员]
*/
private static void initServer()
{
final ZkClient zkClient = new ZkClient("192.168.234.157:2181", 6000, 1000);
List<String> children = zkClient.getChildren(parent);
getChildren(zkClient, children);
zkClient.subscribeChildChanges(parent, new IZkChildListener()
{
public void handleChildChange(String parentPath, List<String> currentChilds) throws Exception
{
getChildren(zkClient, currentChilds);
serverCount = listServer.size();
System.out.println(">>>>>>>>>>>>>>handleChildChange service list ：" + currentChilds.toString());
}
});
}
private static void getChildren(ZkClient zkClient, List<String> children)
{
listServer.clear();
for (String node : children)
{
String pathValue = zkClient.readData(parent + "/" + node);
listServer.add(pathValue);
serverCount = listServer.size();
System.out.println(">>>>>>>>>>>>>> Service list ：" + listServer.toString());
}
}
}
ZkServerScoekt.java
package com.infosys;
import java.net.ServerSocket;
import java.net.Socket;
import org.I0Itec.zkclient.ZkClient;
/**
*
* <一句话功能简述>
* <功能详细描述>
*
* @author Jiayoubing
* @version [版本号,2020年3月28日]
* @see [相关类/方法]
* @since [产品/模块版本]
*/
public class ZkServerScoekt implements Runnable
{
// 设置服务器端口号
private static int port = 18081;
private static String zkServers = "192.168.234.157:2181";
private static int sessionTimeout = 6000;
private static int connectionTimeout = 1000;
public static void main(String[] args)
{
ZkServerScoekt server = new ZkServerScoekt(port);
Thread thread = new Thread(server);
thread.start();
}
public void run()
{
ServerSocket serverSocket = null;
try
{
serverSocket = new ServerSocket(port);
regService();
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)
{
}
}
}
public ZkServerScoekt(int port)
{
this.port = port;
}
// 启动注册服务,需要先创建一个父节点/infosys节点,server在infosys节点下面
private void regService()
{
ZkClient zkClient = new ZkClient(zkServers, sessionTimeout, connectionTimeout);
String path = "/infosys/server" + port;
if (zkClient.exists(path))
{
zkClient.delete(path);
}
zkClient.createEphemeral(path, "127.0.0.1:" + port);
}
}
