Zookeeper实现负载均衡原理
先玩个正常的，好玩的socket编程：
服务端：
首先公共的这个Handler：
package com.toov5.zkDubbo;
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;
}
}
}
}
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 = 18080; //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); //字节的 临时节点 如果服务宕机了 找不到了就
// 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;
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
}
// 获取当前server信息
public static String getServer() {
return listServer.get(0);
}
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();
}
}
}
}
}运行结果：
引申思路
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。
1、会员服务 项目启动时候 会在zk上面创建临时节点 /toov5 对应的value是127.0.0.1
如果是集群 /toov5 下面会会以 节点形式存储 节点名字就是IP+端口 value 分别也是 IP+端口 有些是没有用到value的哦
2、订单直接去使用 /toov5 查询下面的子节点信息，获取到之后。在本地使用负载均衡算法实现调用，决定使用哪个。
127.0.0.1:8080
127.0.0.1:8081
PS： 任何服务的底层都是 socke 技术
socket客户端 （ 客户端去获取注册信息） socket服务器端
废话不多说，项目：
<dependencies>
<dependency>
<groupId>com.101tec</groupId>
<artifactId>zkclient</artifactId>
<version>0.8</version>
</dependency>
</dependencies> 这个不是Apache的哦注意
服务端代码：
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 = 18081; //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); //字节的 临时节点 如果服务宕机了 找不到了就
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) {
}
}
}
}客户端代码：
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;
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
}
// 获取当前server信息
public static String getServer() {
return listServer.get(0);
}
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();
}
}
}
}
}
启动服务端后的结果：
可以看到 去zk注册了信息。服务的名字 和子节点
其中子节点是 临时节点 相当于如果服务宕机了 就查不到了哦
启动三次服务端后：
然后 去zk读取节点信息：
客户端 负载均衡轮训算法
请求次数 % 服务端数 = 服务器端口号的奇数偶数
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.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
ZkClient zkClient = new ZkClient("192.168.91.5",5000,10000);
//读取父节点信息
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();
}
//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();
}
}
}
}
}启动后（后端服务启动三个）：
访问一次：取模算法后的结果
第二次、第三次：
看到结果 太美妙了！
美妙集中在此：
好好欣赏下~~
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