这两天因为项目需求研究了一下Websocket，发现TomCat7与TomCat8还是有些区别的，总的来说TomCat8比较简单，易实现。
网上有很多文章都指出TomCat7需要修改web.xml以及单独导入.jar包，但是我没有修改任何地方，也能连接成功。
- 区别：
1、tomcat7需要建立一个链接类来继承WebSocketServlet，但是tomcat8不需要
2、tomcat使用@WebServlet("/DemoWebSocket")建立URL映射，而tomcat8使用@ServerEndpoint("/DemoWebSocket") - 相同点：
1、jsp代码不需要变
2、链接地址不变
代码是借鉴别人的 - 贴上tomcat7下的代码
package com.scoket.scoketTest;
import java.util.concurrent.atomic.AtomicInteger;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import org.apache.catalina.websocket.StreamInbound;
import org.apache.catalina.websocket.WebSocketServlet;
import com.scoket.scoketTest.HelloMessageInbound;
@WebServlet("/DemoWebSocket")
public class WebSocketTest extends WebSocketServlet {
private static final long serialVersionUID = 1L;
private final AtomicInteger connectionIds = new AtomicInteger(0);
@Override
protected StreamInbound createWebSocketInbound(String arg0,
HttpServletRequest arg1) {
// TODO Auto-generated method stub
return new HelloMessageInbound(connectionIds.getAndIncrement(), arg1
.getSession().getId());
}
}
package com.socket;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.nio.CharBuffer;
import org.apache.catalina.websocket.StreamInbound;
import org.apache.catalina.websocket.WsOutbound;
public class HelloMessageInbound extends StreamInbound {
private String WS_NAME;
private final String FORMAT = "%s : %s";
private final String PREFIX = "ws_";
private String sessionId = "";
public HelloMessageInbound(int id, String _sessionId) {
this.WS_NAME = PREFIX + id;
this.sessionId = _sessionId;
}
@Override
protected void onTextData(Reader reader) throws IOException {
char[] chArr = new char[1024];
int len = reader.read(chArr);
send(String.copyValueOf(chArr, 0, len));
}
@Override
protected void onClose(int status) {
System.out.println(String.format(FORMAT, WS_NAME, "closing ......"));
super.onClose(status);
}
@Override
protected void onOpen(WsOutbound outbound) {
super.onOpen(outbound);
try {
send("hello, my name is " + WS_NAME);
send("session id = " + this.sessionId);
} catch (IOException e) {
e.printStackTrace();
}
}
private void send(String message) throws IOException {
message = String.format(FORMAT, WS_NAME, message); // 推送消息
System.out.println(message);
getWsOutbound().writeTextMessage(CharBuffer.wrap(message));
}
@Override
protected void onBinaryData(InputStream arg0) throws IOException {
}
}
前端jsp
<!DOCTYPE HTML>
<html>
<head>
<title>tomcat7test</title>
<style>
body {padding: 40px;}
#outputPanel {margin: 10px;padding:10px;background: #eee;border: 1px solid #000;min-height: 300px;}
</style>
</head>
<body>
<input type="text" id="messagebox" size="60" />
<input type="button" id="buttonSend" value="Send Message" />
<input type="button" id="buttonConnect" value="Connect to server" />
<input type="button" id="buttonClose" value="Disconnect" />
<br>
<% out.println("Session ID = " + session.getId()); %>
<div id="outputPanel"></div>
</body>
<script type="text/javascript">
var infoPanel = document.getElementById('outputPanel'); // 输出结果面板
var textBox = document.getElementById('messagebox'); // 消息输入框
var sendButton = document.getElementById('buttonSend'); // 发送消息按钮
var connButton = document.getElementById('buttonConnect');// 建立连接按钮
var discButton = document.getElementById('buttonClose');// 断开连接按钮
// 控制台输出对象
var console = {log : function(text) {infoPanel.innerHTML += text + "<br>";}};
// WebSocket演示对象
var demo = {
socket : null, // WebSocket连接对象
host : '', // WebSocket连接 url
connect : function() { // 连接服务器
window.WebSocket = window.WebSocket || window.MozWebSocket;
if (!window.WebSocket) { // 检测浏览器支持
console.log('Error: WebSocket is not supported .');
return;
}
this.socket = new WebSocket(this.host); // 创建连接并注册响应函数
this.socket.onopen = function(){console.log("websocket is opened .");};
this.socket.onmessage = function(message) {console.log(message.data);};
this.socket.onclose = function(){
console.log("websocket is closed .");
demo.socket = null; // 清理
};
},
send : function(message) { // 发送消息方法
if (this.socket) {
this.socket.send(message);
return true;
}
console.log('please connect to the server first !!!');
return false;
}
};
// 初始化WebSocket连接 url
//demo.host=(window.location.protocol == 'http:') ? 'ws://' : 'wss://' ;
//demo.host += window.location.host + '/tomcat7test/DemoWebSocket';
demo.host = 'ws://localhost:9090/tomcat7test/DemoWebSocket'
console.log(demo.host);
// 初始化按钮点击事件函数
sendButton.onclick = function() {
var message = textBox.value;
if (!message) return;
if (!demo.send(message)) return;
textBox.value = '';
};
connButton.onclick = function() {
if (!demo.socket) demo.connect();
else console.log('websocket already exists .');
};
discButton.onclick = function() {
if (demo.socket) demo.socket.close();
else console.log('websocket is not found .');
};
</script>
</html>
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jar截图
jar截图
