Websocket示例不起作用

Question

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());
    }
}

我用Tomcat 7.0.47,我检查链接:ws://localhost/Tests/chat.我是否需要注册此websocket或添加一些内容web.xml？知道为什么不适合我吗？

Answer 1

尝试在Tomcat 7.0.47上使用WebSocket API时遇到了同样的问题.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.

在浪费了很多时间后,我发现这是因为我设置了依赖性javax.websocket-api.我正在使用具有默认范围的Maven,compile因为Tomcat websocket-api.jar在其lib文件夹中存在问题.设置依赖项以provided解决它.

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

希望这可以帮助

值得注意的是,如果在Apache后面运行,您将需要mod_proxy_wstunnel并且如果使用IIS,您将需要8.0版,因为之前的任何东西都不支持websockets.