java websocket 实现

环境：jdk1.8 + Tomcat 8

IDE：IntelliJ IDEA 2016.2.4



WebSocket.java

package websocket;

import org.java_websocket.WebSocketImpl;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;

import java.net.InetSocketAddress;
import java.net.UnknownHostException;

/**
* Created by Administrator on 2016/9/13.
*/
public class WebSocket extends WebSocketServer {

int j=0;
int h=0;
int e=0;
int l=0;

public WebSocket(InetSocketAddress address) {
super(address);
System.out.println("地址" + address);
}

public WebSocket(int port) throws UnknownHostException {
super(new InetSocketAddress(port));
System.out.println("端口" + port);
}

/**
* 触发连接事件
* @param conn
* @param handshake
*/
@Override
public void onOpen(org.java_websocket.WebSocket conn, ClientHandshake handshake) {
System.out.println("有人连接Socket conn:" + conn);
l++;
}

/**
* 触发关闭事件
* @param conn
* @param message
* @param reason
* @param remote
*/
@Override
public void onClose(org.java_websocket.WebSocket conn, int message, String reason, boolean remote) {
userLeave(conn);
}

/**
* 客户端发送消息到服务器是触发事件
* @param conn
* @param message
*/
@Override
public void onMessage(org.java_websocket.WebSocket conn, String message) {
if(message != null) {
//将用户加入
this.userJoin(message, conn);
}
}

/**
* 触发异常事件
* @param conn
* @param message
*/
@Override
public void onError(org.java_websocket.WebSocket conn, Exception message) {
System.out.println("Socket异常:" + message.toString());
e++;
}

/**
* 用户下线处理
* @param conn
*/
public void userLeave(org.java_websocket.WebSocket conn) {
String user = WebSocketPool.getUserByKey(conn);
boolean b = WebSocketPool.removeUser(conn); // 在连接池中移除连接
if (b) {
WebSocketPool.sendMessage(user); // 把当前用户从所有在线用户列表中删除
String leaveMsg = "[系统]" + user + "下线了";
WebSocketPool.sendMessage(leaveMsg); // 向在线用户发送当前用户退出的信息
}
}

public void userJoin(String user, org.java_websocket.WebSocket conn) {
WebSocketPool.sendMessage(user); // 把当前用户加入到所有在线用户列表中
String joinMsg = "[系统]" + user + "上线了！";
WebSocketPool.sendMessage(joinMsg); // 向所有在线用户推送当前用户上线的消息
WebSocketPool.addUser(user, conn); // 向连接池添加当前的连接的对象
WebSocketPool.sendMessageToUser(conn, WebSocketPool.getOnlineUser().toString());
// 向当前连接发送当前在线用户的列表
}

public static void main(String[] args) throws InterruptedException{
//        System.out.println("开始启动webSocket");
//        WebSocketImpl.DEBUG = false;
//        int port = 8888; // 端口随便设置，只要不跟现有端口重复就可以了
//        WebSocket s =null;
//        try {
//            s = new WebSocket(port);
//            s.start();
//        } catch (UnknownHostException e1) {
//            System.out.println("启动webSocket失败！");
//            e1.printStackTrace();
//        }
//        System.out.println("启动webSocket成功！");
}
}

socket主要函数

main方法是后面测试用的，等会会提到。

WebSocketPool.java

package websocket;

import java.util.*;
import org.java_websocket.WebSocket;

/**
* Created by Administrator on 2016/9/13.
*/
public class WebSocketPool {
private static final Map<WebSocket, String> userconnections = new HashMap<WebSocket, String>();

/**
* 获取用户名
* @param conn
* @return
*/
public static String getUserByKey(WebSocket conn) {
return userconnections.get(conn);
}

/**
* 获取在线总数
* @return
*/
public static int getUserCount() {
return userconnections.size();
}

/**
* 获取WebSocket
* @param user
* @return
*/
public static WebSocket getWebSocketByUser(String user) {
Set<WebSocket> keySet = userconnections.keySet();
synchronized (keySet) {
for (WebSocket conn : keySet) {
String cuser = userconnections.get(conn);
if (cuser.equals(user)) {
return conn;
}
}
}
return null;
}

/**
* 向连接池中添加连接
* @param user
* @param conn
*/
public static void addUser(String user, WebSocket conn) {
userconnections.put(conn, user); // 添加连接
}

/**
* 获取所有的在线用户
* @return
*/
public static Collection<String> getOnlineUser() {
List<String> setUsers = new ArrayList<String>();
Collection<String> setUser = userconnections.values();
for (String u: setUser) {
setUsers.add(u);
}
return setUsers;
}

/**
* 移除连接池中的连接
* @param conn
* @return
*/
public static boolean removeUser(WebSocket conn) {
if (userconnections.containsKey(conn)) {
userconnections.remove(conn); // 移除连接
return true;
} else
return false;
}

/**
* 向特定的用户发送数据
* @param conn
* @param message
*/
public static void sendMessageToUser(WebSocket conn, String message) {
if (null != conn) {
conn.send(message);
}
}

public static void sendMessage(String message) {
Set<WebSocket> keySet = userconnections.keySet();
synchronized (keySet) {
for (WebSocket conn : keySet) {
String user = userconnections.get(conn);
if (user != null) { conn.send(message);
}
}
}
}

}

连接池相关函数
http://www.blue-zero.com/websocket/
作者： 手插口袋_

链接：http://www.imooc.com/article/12401

来源：慕课网

本文原创发布于慕课网 ，转载请注明出处，谢谢合作！
跑main方法，看看是否能正常启动（看控制台很清楚的），然后打开http://www.blue-zero.com/websocket/

如下图所示


http://www.blue-zero.com/websocket/
作者： 手插口袋_

链接：http://www.imooc.com/article/12401

来源：慕课网

本文原创发布于慕课网 ，转载请注明出处，谢谢合作！

（我以后也要写一个类似的！！！！）

Web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1">
<display-name></display-name>
<filter>
<filter-name>startFilter</filter-name>
<filter-class>filter.startFilter</filter-class>
</filter>
<servlet>
<servlet-name>TestServlet</servlet-name>
<servlet-class>servlet.TestServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>TestServlet</servlet-name>
<url-pattern>/TestServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

好像少了什么东西，但是不影响结果

startFilter .java

package filter;

import java.io.IOException;
import java.net.UnknownHostException;
import javax.servlet.Filter;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;

import org.java_websocket.WebSocketImpl;

import websocket.WebSocket;

/**
* Created by Administrator on 2016/9/13.
*/
public class startFilter implements Filter {

public void destroy() {
}

public void doFilter(javax.servlet.ServletRequest req, javax.servlet.ServletResponse resp, javax.servlet.FilterChain chain) throws javax.servlet.ServletException, IOException {
chain.doFilter(req, resp);
}

/**
* 初始化
* @param fc
* @throws ServletException
*/
public void init(FilterConfig fc) throws ServletException {
this.starWebSocketOnline();
}

/**
* 启动socket服务
*/
public void starWebSocketOnline() {
System.out.println("开始启动webSocket");
WebSocketImpl.DEBUG = false;
int port = 8888;
WebSocket s = null;
try {
s = new WebSocket(port);
s.start();
} catch (UnknownHostException e) {
System.out.println("启动webSocket失败！");
e.printStackTrace();
}
System.out.println("启动webSocket成功！");
}

}

过滤器启动socket服务，这里实质跟main方法差不多

TestServlet .java

package servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
* Created by Administrator on 2016/9/14.
*/
public class TestServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
super.doPost(req, resp);
}

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// super.doPost(req, resp);
System.out.println("content" + req.getParameter("content"));
req.getSession().setAttribute("content", req.getParameter("content"));
req.getRequestDispatcher("index.jsp").forward(req, resp);
}
}

一个很简单的servlet

index .jsp

<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2016/9/13
Time: 10:35
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.util.*" %>
<%
String path = request.getContextPath();
String basepath = request.getScheme() + "://" + request.getServerName() + ":" +
request.getServerPort() + path + "/";
%>
<html>
<head>
<base href="<%=basepath%>">

<title>sunnylinner的WebSocket</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

<script src="js/websocket.js"></script>
</head>
<body>
<input type="hidden" value="${content}" id="content">
<form action="TestServlet" method="post">
content: <input type="text" name="content">
<button type="submit">登陆</button>
</form>
<span id="span">

</span>
<span id="span1">

</span>
</body>
</html>

websocket .js

/**
* Created by Administrator on 2016/9/14.
*/
var ws = new WebSocket("ws://127.0.0.1:8888");
ws.onopen = function () { // 当websocket创建成功，即会触发onopen事件
var content = document.getElementById("content").value;
if (content == null && content == ""){
ws.send("sunnylinner"); // 用于将消息发送到服务端
document.getElementById("span1").innerHTML="1@@1";
} else {
ws.send(content);
document.getElementById("span1").innerHTML="2@@2";
}
};
ws.onmessage = function (evt) {
// 当客户端收到服务端发送来的消息时，会触发onmessage事件，参数evt.data中包含server传输过来的数据
document.getElementById("span1").innerHTML="3@@3";
document.getElementById("span").innerHTML="当前在线人数为：" + evt.data;
};
ws.onclose = function () {
// 当客户端收到服务端发送的关闭连接的请求时，触发onclose事件
alert("WebSocketClosed!");
};
ws.onerror = function () {
// 如果出现连接，处理，接收，发送数据失败的时候就会触发onerror事件
alert("WebSocketError!");
}

应该没剩下了，可以直接跑了。至于最后的显示效果， 我就不放出来了，自己去玩吧，有些方法都写好了，可以去实现跟过可能高级一点的功能。

有什么问题在下面提出来吧

资料参考：慕课网