我正在努力使我的第一个简单的客户端servlet应用程序使用web套接字和tomcat 9服务器。我在网上找到了这个例子。我有下一个错误：
(index):17 WebSocket connection to 'ws://localhost:8080/JavaWebSocket/ws' failed:
Error during WebSocket handshake: Unexpected response code: 404"
是这条线：
var webSocket = new WebSocket("ws://localhost:8080/JavaWebSocket/ws")"
我认为初始化应该是
var webSocket = new WebSocket("ws://localhost:8080/[nameOfTheClassWithWebSocket]/ws");
但它也不起作用：(我什么都试过了：(我解决不了这个问题：(
Java代码和带有项目方案的Jsp文件如下。
Java代码：
package socket;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.server.ServerEndpoint;
@ServerEndpoint("/ws")
public class WebSocketServerExample {
@OnOpen
public void onOpen(){
System.out.println("Open Connection ...");
}
@OnClose
public void onClose(){
System.out.println("Close Connection ...");
}
@OnMessage
public String onMessage(String message){
System.out.println("Message from the client: " + message);
String echoMsg = "Echo from the server : " + message;
return echoMsg;
}
@OnError
public void onError(Throwable e){
e.printStackTrace();
}
}
jsp文件：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<meta charset="UTF-8">
<title>Tomcat WebSocket</title>
</head>
<body>
<form>
<input id="message" type="text">
<input onclick="wsSendMessage();" value="Echo" type="button">
<input onclick="wsCloseConnection();" value="Disconnect" type="button">
</form>
<br>
<textarea id="echoText" rows="5" cols="30"></textarea>
<script type="text/javascript">
var webSocket = new WebSocket("ws://localhost:8080/JavaWebSocket/ws");
var echoText = document.getElementById("echoText");
echoText.value = "";
var message = document.getElementById("message");
webSocket.onopen = function(message){ wsOpen(message);};
webSocket.onmessage = function(message){ wsGetMessage(message);};
webSocket.onclose = function(message){ console.log(message);};
webSocket.onerror = function(message){ console.log(message);};
function wsOpen(message){
echoText.value += "Connected ... n";
}
function wsSendMessage(){
webSocket.send(message.value);
echoText.value += "Message sended to the server : " + message.value + "n";
message.value = "";
}
function wsCloseConnection(){
webSocket.close();
}
function wsGetMessage(message){
echoText.value += "Message received from to the server : " + message.data + "n";
}
function wsClose(message){
echoText.value += "Disconnect ... n";
}
function wserror(message){
echoText.value += "Error ... n";
}
</script>
</body>
</html>
项目方案
您的url将是var webSocket=新webSocket("ws://localhost:[port]/appcontext/ws"(">