不能访问类型为Server的封闭实例

Question

我在Java中遇到了一个奇怪的问题,这是我以前从未见过的.

错误是"无法访问类型为Server的封闭实例.必须使用类型为Server的封闭实例限定分配(例如,xnew A(),其中x是Server的实例)."

我评论过的那一行是错误发生的地方.

package game;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;

public class Server {

    private static List<ThreadModtagClient> clients;

    class ReceiveDataListener implements SocketListener {

        @Override
        public void dataReceived(ThreadModtagClient client, String data) {

        }   
    }

    /**
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub

        clients = new ArrayList<ThreadModtagClient>();

        ServerSocket welcomeSocket = new ServerSocket(16567);

        while (true) {
            Socket connectionSocket = welcomeSocket.accept();

            ThreadModtagClient client = new ThreadModtagClient(connectionSocket);
            ReceiveDataListener listener = new ReceiveDataListener(); // <--- this is where the error occurs
            client.addSocketListener(listener);
            clients.add(client);
        }

    }
}

class ThreadModtagClient extends Thread implements SocketThread {

    private BufferedReader inFromClient;
    private DataOutputStream outToClient;

    private Player player;

    private List<SocketListener> listeners;


    public ThreadModtagClient(Socket connection) throws IOException {
        inFromClient = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        outToClient = new DataOutputStream(connection.getOutputStream());
        listeners = new ArrayList<SocketListener>();

    }

    public void addSocketListener(SocketListener listener) {
        listeners.add(listener);
    }

    public void removeSocketListener(SocketListener listener) {
        listeners.remove(listener);
    }

    public Player getPlayer() {
        return player;
    }

    public void setPlayer(Player player) {
        this.player = player;
    }


    public void sendData(String data) throws IOException {
        outToClient.writeChars(data);
    }

    public void run() {

        while (true) {
            try {

                String data = inFromClient.readLine();

                for(SocketListener listener : listeners) {
                    listener.dataReceived(this, data);
                }

            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch(NoSuchElementException e1) {
                e1.printStackTrace();
            }
        }
    }
}

Answer 1

Server.ReceiveDataListener是一个(非静态)内部类.您是从静态上下文创建它.您需要提供一个Server外部实例的实例.但是,几乎可以肯定,您希望ReceiveDataListener成为静态嵌套类,或者可能是外部类.

Answer 2

好的错误告诉你到底需要做什么.ReceiveDataListener是一个非静态内部类,必须通过外部类(Server)的对象进行访问.您有三个选择:1.获取编译器的建议(通过Server的对象访问)2.使ReceiveDataListener静态3.将ReceiveDataListener拉出到单独的.java并使用它.

HTH