如何在Jetty 9中访问实例化的WebSockets? [英] How do I access instantiated WebSockets in Jetty 9?
问题描述
这可能很明显,但我对这个范例不熟悉。我创建一个Jetty服务器并注册我的websocket类,如下所示:
This is probably obvious, but I am new to this paradigm. I create a Jetty Server and register my websocket class as follows:
Server server = new Server(8080);
WebSocketHandler wsHandler = new WebSocketHandler()
{
@Override
public void configure(WebSocketServletFactory factory)
{
factory.register(MyEchoSocket.class);
}
};
server.setHandler(wsHandler);
websocket收到的邮件很好。我还希望能够在没有首先收到客户端消息的情况下从服务器发送消息。如何访问连接打开时创建的MyEchoSocket实例?或者,更一般地说,如何在MyEchoSocket中的onText方法之外的套接字上发送消息?
The websocket receives messages fine. I would like to also be able to send messages out from the server without having first received a message from the client. How do I access the MyEchoSocket instance that's created when the connection opens? Or, more generally, how do I send messages on the socket outside of the onText method in MyEchoSocket?
推荐答案
两种常用技巧,这里以超简化的聊天室概念呈现。
Two common techniques, presented here in a super simplified chatroom concept.
选项#1:让WebSocket报告将其状态恢复到中心位置
@WebSocket
public class ChatSocket {
public Session session;
@OnWebSocketConnect
public void onConnect(Session session) {
this.session = session;
ChatRoom.getInstance().join(this);
}
@OnWebSocketMessage
public void onText(String message) {
ChatRoom.getInstance().writeAllMembers("Hello all");
}
@OnWebSocketClose
public void onClose(int statusCode, String reason) {
ChatRoom.getInstance().part(this);
}
}
public class ChatRoom {
private static final ChatRoom INSTANCE = new ChatRoom();
public static ChatRoom getInstance()
{
return INSTANCE;
}
private List<ChatSocket> members = new ArrayList<>();
public void join(ChatSocket socket)
{
members.add(socket);
}
public void part(ChatSocket socket)
{
members.remove(socket);
}
public void writeAllMembers(String message)
{
for(ChatSocket member: members)
{
member.session.getRemote().sendStringByFuture(message);
}
}
public void writeSpecificMember(String memberName, String message)
{
ChatSocket member = findMemberByName(memberName);
member.session.getRemote().sendStringByFuture(message);
}
public ChatSocket findMemberByName(String memberName)
{
// left as exercise to reader
}
}
然后只需使用中心位置与您选择的网址对话。
Then simply use the central location to talk to the websockets of your choice.
ChatRoom.getInstance().writeSpecificMember("alex", "Hello");
// or
ChatRoom.getInstance().writeAllMembers("Hello all");
选项#2:使用WebSocketCreator手动创建WebSocket
@WebSocket
public class ChatSocket {
public ChatRoom chatroom;
public ChatSocket(ChatRoom chatroom)
{
this.chatroom = chatroom;
}
@OnWebSocketConnect
public void onConnect(Session session) {
chatroom.join(this);
}
@OnWebSocketMessage
public void onText(String message) {
chatroom.writeAllMembers(message);
}
@OnWebSocketClose
public void onClose(int statusCode, String reason) {
chatroom.part(this);
}
}
public class ChatCreator implements WebSocketCreator
{
private ChatRoom chatroom;
public ChatCreator(ChatRoom chatroom)
{
this.chatroom = chatroom;
}
public Object createWebSocket(UpgradeRequest request,
UpgradeResponse response)
{
// We want to create the Chat Socket and associate
// it with our chatroom implementation
return new ChatSocket(chatroom);
}
}
public class ChatHandler extends WebSocketHandler
{
private ChatRoom chatroom = new ChatRoom();
@Override
public void configure(WebSocketServletFactory factory)
{
factory.setCreator(new ChatCreator(chatroom));
}
}
此时您可以使用与上述相同的技巧与您选择的websockets交谈。
At this point you can use the same techniques as above to talk to the websockets of your choice.
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