按照网上的一篇教程来的。
控制器：
package com.jfinal.common.websocket;
import java.io.IOException;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.atomic.AtomicInteger;
import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
import com.jfinal.log.Log;
@ServerEndpoint("/websocket")
public class WebSocketController {
static Log log = Log.getLog(WebSocketController.class);
private static final String GUEST_PREFIX = "Guest";
private static final AtomicInteger connectionIds = new AtomicInteger(0);
private static final Set<WebSocketController> connections = new CopyOnWriteArraySet<>();
@OnOpen
public void onOpen(Session session) {
}
@OnClose
public void onClose(Session session) {
}
@OnMessage
public void onMessage(String requestJson, Session session) throws IOException {
session.getBasicRemote().sendText(requestJson);
}
}Handler
package com.jfinal.common.websocket;
import java.util.regex.Pattern;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.jfinal.handler.Handler;
import com.jfinal.kit.StrKit;
public class WebSocketHandler extends Handler{
private Pattern filterUrlRegxPattern;
public WebSocketHandler(String filterUrlRegx) {
if (StrKit.isBlank(filterUrlRegx))
throw new IllegalArgumentException("The para filterUrlRegx can not be blank.");
filterUrlRegxPattern = Pattern.compile(filterUrlRegx);
}
@Override
public void handle(String target, HttpServletRequest request, HttpServletResponse response, boolean[] isHandled) {
if (filterUrlRegxPattern.matcher(target).find())
return ;
else
next.handle(target, request, response, isHandled);
}
}配置
@Override
public void configHandler(Handlers me) {
me.add(new ContextPathHandler("ctx"));
me.add(new WebSocketHandler("^/websocket"));
}HTML
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8"> <!-- for HTML5 -->
<title>Java后端WebSocket的Tomcat实现</title>
</head>
<body>
Welcome<br/><input id="text" type="text"/>
<button onclick="send()">发送消息</button>
<hr/>
<button onclick="closeWebSocket()">关闭WebSocket连接</button>
<hr/>
<div id="message"></div>
</body>
<script type="text/javascript">
var websocket = null;
//判断当前浏览器是否支持WebSocket
if ('WebSocket' in window) {
websocket = new WebSocket("ws://localhost:81/websocket");
}
else {
alert('当前浏览器 Not support websocket')
}
//连接发生错误的回调方法
websocket.onerror = function () {
setMessageInnerHTML("WebSocket连接发生错误");
};
//连接成功建立的回调方法
websocket.onopen = function () {
setMessageInnerHTML("WebSocket连接成功");
}
//接收到消息的回调方法
websocket.onmessage = function (event) {
setMessageInnerHTML(event.data);
}
//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();
}
//将消息显示在网页上
function setMessageInnerHTML(innerHTML) {
document.getElementById('message').innerHTML += innerHTML + '<br/>';
}
//关闭WebSocket连接
function closeWebSocket() {
websocket.close();
}
//发送消息
function send() {
var message = document.getElementById('text').value;
websocket.send(message);
}
</script>
</html>结果运行的时候是404，找了一天问题了。烦请赐教。
项目：JFinal
终极解决方法是设置断点，单步调试到 WebSocketHandler 中去看程序走向，不要去猜测程序的行为，要调试