[英]cannot instantiate a WebSocket in my grizzly-project under use of createSocket-Method
我試圖在基於Grizzly的服務器中啟用WebSockets並進行服務器推送,但出現此錯誤:
WARNING: GRIZZLY0013: Exception during FilterChain execution
java.lang.NoClassDefFoundError: javax/servlet/http/HttpServletResponse
.
.
.
Caused by: java.lang.ClassNotFoundException: javax.servlet.http.HttpServletResponse
在我的代碼中,我沒有使用Servlet,所以我不知道為什么會收到此錯誤。 這是我的整個代碼,該代碼基於此示例https://jaxenter.com/tutorial-pushing-browser-updates-using-websockets-in-glassfish-105970.html
1)啟動我的灰熊服務器的代理程序類。 在這里,我沒有使用Servlet就注冊了EchoApp。
public class Agent{
public void runServer() throws UnrecoverableKeyException, KeyManagementException, NoSuchAlgorithmException, CertificateException, FileNotFoundException, KeyStoreException,
IOException, InterruptedException {
HttpServer server = HttpServer.createSimpleServer();
final WebSocketAddOn webSocketAddon = new WebSocketAddOn();
for (NetworkListener listener : server.getListeners()) {
listener.setChunkingEnabled(false);
listener.registerAddOn(webSocketAddon);
}
EchoApp echoApplication = new EchoApp();
WebSocketEngine.getEngine().register(echoApplication);
// start the server
server.start();
Thread.currentThread().join();
}
public static void main(String args []){
Agent agent = new Agent();
try {
agent.runServer();
} catch (UnrecoverableKeyException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (KeyManagementException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (CertificateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (KeyStoreException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
2)這是我的EchoApplication,它擴展了WebSocketApplication:
public class EchoApp extends WebSocketApplication{
/** The logger. */
private static final Logger logger = Logger.getLogger(EchoApp.class.getName());
@Override
public boolean isApplicationRequest(HttpRequestPacket request) {
if (request.getRequestURI().toString().endsWith("/echo"))
{
return true;
}
else
{
return false;
}
}
@Override
public WebSocket createSocket(ProtocolHandlerhandler,HttpRequestPacket requestPacket,
WebSocketListener... listeners) {
System.out.println("Websocket will be Created");
return new EchoSocket(handler, requestPacket,listeners);//The exception will be thrown here!!!!!!!!!
}
}
3)這是我的EchoSocket類:
class EchoSocket extends DefaultWebSocket implements Runnable {
private Thread myThread;
private boolean connected = false;
//handler
EchoSocket (ProtocolHandler handler,HttpRequestPacket requestPacket, WebSocketListener... listeners){
super(handler,requestPacket,listeners);
System.out.println("instantiate");
}
@Override
public void onConnect() {
System.out.println("connected");
myThread = new Thread(this);
connected = true;
myThread.start();
super.onConnect();
}
public void run() {
if(connected) {
System.out.println("connected");
send("push");
}
}
}
這是構建項目所需的依賴項:
<dependency>
<groupId>org.glassfish.grizzly</groupId>
<artifactId>grizzly-websockets</artifactId>
<version>2.3.22</version>
</dependency>
<dependency>
<groupId>org.glassfish.grizzly</groupId>
<artifactId>grizzly-http-server</artifactId>
<version>2.3.22</version>
</dependency>
<dependency> //I added this dependency when I get the problem but it does not solve it
<groupId>org.glassfish.grizzly</groupId>
<artifactId>grizzly-http-servlet</artifactId>
<version>2.3.22</version>
</dependency>
我從未使用過Servlet,也不知道我的代碼中是否需要它們?
如果我需要Servlet:在代碼中的哪里可以使用它們?
Grizzly只有一個用於websocket支持的模塊,其中包括客戶端API和服務器端API。 而服務器端API則依賴於要在類路徑中顯示的servlet-api。 因此,請包括以下Maven依賴項:
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
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