使用websocket实现web客户端与服务器之间的实时通讯。以下是个简单的demo。
前端页面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fun"%>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>
<c:set var="baseurl" value="${pageContext.request.contextPath}/"></c:set> <html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>web_socket</title> <script type="text/javascript" src="${baseurl}static/js/jquery-2.1.1.js"></script>
<style type="text/css">
.connector {width: 500px;}
</style>
</head>
<body>
Welcome
<br/>
<input id="text" type="text"/>
<button onclick="sendToOne(10008)">发消息给个人</button>
<button onclick="sendToAll(0)">发消息给所有人</button>
<hr/>
<button onclick="closeWebSocket()">关闭WebSocket连接</button>
<hr/>
<div id="message"></div>
</body>
<script type="text/javascript">
var websocket = null;
var host = document.location.host; //判断当前浏览器是否支持WebSocket
if ('WebSocket' in window) {
console.info("浏览器支持Websocket");
websocket = new WebSocket('ws://'+host+'/${baseurl}/webSocketServer/${userID}');
} else {
console.info('当前浏览器 Not support websocket');
} //连接发生错误的回调方法
websocket.onerror = function() {
console.info("WebSocket连接发生错误");
setMessageInnerHTML("WebSocket连接发生错误");
} //连接成功建立的回调方法
websocket.onopen = function() {
console.info("WebSocket连接成功");
setMessageInnerHTML("WebSocket连接成功");
} //接收到消息的回调方法
websocket.onmessage = function(event) {
console.info("接收到消息的回调方法");
console.info("这是后台推送的消息："+event.data);
setMessageInnerHTML(event.data);
console.info("webSocket已关闭！");
} //连接关闭的回调方法
websocket.onclose = function() {
setMessageInnerHTML("WebSocket连接关闭");
} //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
window.onbeforeunload = function() {
closeWebSocket();
} //关闭WebSocket连接
function closeWebSocket() {
websocket.close();
} //将消息显示在网页上
function setMessageInnerHTML(innerHTML) {
document.getElementById('message').innerHTML += innerHTML + '<br/>';
} //发送消息给其他客户端
function sendToOne(receiverId) {
var messageContent = document.getElementById('text').value;
var message = {};
message.senderId = "${userID}";
message.receiverId = receiverId;
message.messageContent = messageContent;
websocket.send(JSON.stringify(message));
} //发送消息给所有人
function sendToAll() {
var messageContent = document.getElementById('text').value;
var message = {};
message.senderId = "${userID}";
message.receiverId = "0";
message.messageContent = messageContent;
websocket.send(JSON.stringify(message));
}
</script>
</html>
后台代码
import java.util.Date;
public class WebSocketMessage {
/**
* 发送者ID
*/
private String senderId;
/**
* 接受者ID, 如果为0, 则发送给所有人
*/
private String receiverId;
/**
* 会话内容
*/
private String messageContent;
/**
* 发送时间
*/
private Date sendTime;
public String getSenderId() {
return senderId;
}
public void setSenderId(String senderId) {
this.senderId = senderId;
}
public String getReceiverId() {
return receiverId;
}
public void setReceiverId(String receiverId) {
this.receiverId = receiverId;
}
public String getMessageContent() {
return messageContent;
}
public void setMessageContent(String messageContent) {
this.messageContent = messageContent;
}
public Date getSendTime() {
return sendTime;
}
public void setSendTime(Date sendTime) {
this.sendTime = sendTime;
}
}import javax.servlet.http.HttpServletResponse; import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView; @Controller
@RequestMapping("webSocket")
public class WebSocketController { @RequestMapping(value = "messagePage/{userID}")
public ModelAndView messagePage(@PathVariable String userID, HttpServletResponse response) {
ModelAndView mav = new ModelAndView();
mav.addObject("userID", userID);
mav.setViewName("web_socket");
return mav;
}
}
import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap; import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint; import com.alibaba.fastjson.JSON;
import com.utime.facade.model.systemplate.WebSocketMessage; @ServerEndpoint("/webSocketServer/{userID}")
public class WebSocketServer {
// 连接客户端数量
private static int onlineCount = 0;
// 所有的连接客户端
private static Map<String, WebSocketServer> clients = new ConcurrentHashMap<String, WebSocketServer>();
// 当前客户端连接的唯一标示
private Session session;
// 当前客户端连接的用户ID
private String userID; /**
* 客户端连接服务端回调函数
*
* @param userID 用户ID
* @param session 会话
* @throws IOException
*/
@OnOpen
public void onOpen(@PathParam("userID") String userID, Session session) throws IOException {
this.userID = userID;
this.session = session; addOnlineCount();
clients.put(userID, this);
System.out.println("WebSocket日志: 有新连接加入！当前在线人数为" + getOnlineCount());
} @OnClose
public void onClose() throws IOException {
clients.remove(userID);
subOnlineCount();
System.out.println("WebSocket日志: 有一连接关闭！当前在线人数为" + getOnlineCount());
} /**
* 接受到来自客户端的消息
*
* @param message
* @throws IOException
*/
@OnMessage
public void onMessage(String message) throws IOException {
System.out.println("WebSocket日志: 来自客户端的消息:" + message);
WebSocketMessage webSocketMessage = JSON.parseObject(message, WebSocketMessage.class); // 发送消息给所有客户端
if ("0".equals(webSocketMessage.getReceiverId())) {
for (WebSocketServer item : clients.values()) {
item.session.getAsyncRemote().sendText(webSocketMessage.getMessageContent());
System.out.println("WebSocket日志: ID为"+ webSocketMessage.getSenderId() +"的用户给ID为"+ item.userID +"的客户端发送:" + webSocketMessage.getMessageContent());
}
} else { // 发送消息给指定ID的客户端
for (WebSocketServer item : clients.values()) {
if (item.userID.equals(webSocketMessage.getReceiverId())){
// 发消息给指定客户端
item.session.getAsyncRemote().sendText(webSocketMessage.getMessageContent());
System.out.println("WebSocket日志: ID为"+ webSocketMessage.getSenderId() +"的用户给ID为"+ item.userID +"的客户端发送:" + webSocketMessage.getMessageContent());
if (!webSocketMessage.getSenderId().equals(webSocketMessage.getReceiverId())) {
// 发消息给自己
this.session.getAsyncRemote().sendText(webSocketMessage.getMessageContent());
System.out.println("WebSocket日志: ID为"+ webSocketMessage.getSenderId() +"的用户给ID为"+ this.userID +"的客户端发送:" + webSocketMessage.getMessageContent());
}
break;
}
}
}
} /**
* 服务端报错了
*
* @param session
* @param error
*/
@OnError
public void onError(Session session, Throwable error) {
System.out.println("WebSocket日志: 发生错误");
error.printStackTrace();
} /**
* 客户端连接数+1
*/
public static synchronized void addOnlineCount() {
WebSocketServer.onlineCount++;
} /**
* 客户端连接数-1
*/
public static synchronized void subOnlineCount() {
WebSocketServer.onlineCount--;
} public static synchronized int getOnlineCount() {
return onlineCount;
} public static synchronized Map<String, WebSocketServer> getClients() {
return clients;
}
}
写这个的目的只是为了自己做个记录。