Websocket示例不起作用 [英] Websocket example won't work

问题描述

我尝试运行这个例子：

import java.util.logging.Level;
import java.util.logging.Logger;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

@ServerEndpoint(value = "/chat")
public class ChatServer {

    private static final Logger LOGGER = 
            Logger.getLogger(ChatServer.class.getName());

    @OnOpen
    public void onOpen(Session session) {
        LOGGER.log(Level.INFO, "New connection with client: {0}", 
                session.getId());
    }

    @OnMessage
    public String onMessage(String message, Session session) {
        LOGGER.log(Level.INFO, "New message from Client [{0}]: {1}", 
                new Object[] {session.getId(), message});
        return "Server received [" + message + "]";
    }

    @OnClose
    public void onClose(Session session) {
        LOGGER.log(Level.INFO, "Close connection for client: {0}", 
                session.getId());
    }

    @OnError
    public void onError(Throwable exception, Session session) {
        LOGGER.log(Level.INFO, "Error for client: {0}", session.getId());
    }
}

我使用 Tomcat 7.0。 47 ，我检查链接： ws：// localhost / Tests / chat 。
我是否需要注册此websocket或在 web.xml 中添加一些内容？
任何想法为什么不适合我？

I use Tomcat 7.0.47, I check link: ws://localhost/Tests/chat. Do I need register this websocket or add some things in web.xml? Any idea why is not working for me?

推荐答案

我在Tomcat上尝试使用WebSocket API遇到了同样的问题7.0.47。客户端显示的错误消息根本没有任何帮助，我的服务器端端点从未被创建过。

I had the same problem trying to use WebSocket API on Tomcat 7.0.47. The error message being displayed client side wasn't any help at all and my server side endpoint was never being created.

在浪费了很多时间后，我发现这是因为我设置了 javax.websocket-api 的依赖关系。我正在使用默认范围为 compile 的Maven，这会导致问题，因为Tomcat有 websocket-api.jar 在其lib文件夹中。将依赖项设置为提供解决了它。

After much wasted time I found it was due to way I had set the dependency for javax.websocket-api. I'm using Maven which has the default scope as compile which causes problems as Tomcat has the websocket-api.jar in its lib folder. Setting the dependency to provided solved it.

    <dependency>
      <groupId>javax.websocket</groupId>
      <artifactId>javax.websocket-api</artifactId>
      <version>1.0</version>
      <scope>provided</scope>
    </dependency>

希望这有帮助

它也值得注意如果在Apache后面运行，你将需要 mod_proxy_wstunnel ，如果使用IIS，你将需要8.0版，因为之前的任何东西都不支持websockets。

It's also worth noting that if running behind Apache you will need mod_proxy_wstunnel and if using IIS you will need version 8.0 as anything prior does not support websockets.

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