Java网络问题：java.net.ConnectException：连接被拒绝：connect

java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at EchoClient.main(EchoClient.java:8)

这是程序：

import java.io.*;
import java.net.*;
import java.util.*;

public class EchoClient{
    public static void main(String[] args) {
        try{
            Socket client = new Socket(InetAddress.getLocalHost(), 1234);
            InputStream clientIn = client.getInputStream();
            OutputStream clientOut = client.getOutputStream();
            PrintWriter pw = new PrintWriter(clientOut);
            BufferedReader br = new BufferedReader(new InputStreamReader(clientIn));
            Scanner stdIn = new Scanner(System.in);
            System.out.println("Input Message:");
            pw.println(stdIn.nextLine());
            System.out.println("Recieved Message:");
            System.out.println(br.readLine());
            pw.close();
            br.close();
            client.close();
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}

我使用Windows 7,我已关闭Windows防火墙,但没有防病毒软件.

但是,当您成功连接时,还有其他问题. pw.println(stdIn.nextLine());可能不会将内容发送到服务器,则需要执行pw.flush();.真正发送内容,或者您​​可以使用自动刷新功能创建PrintWriter：

 pw = new PrintWriter(clientOut, true);

如果您需要一台EchoServer,那么如果您添加了我上面描述的刷新,我只写了一个与您的客户端一起使用的服务器：

public class EchoServer {
    public static void main(String[] args) throws IOException {
        ServerSocket ss = new ServerSocket(1234);

        while (true) {
            // accept the connection 
            Socket s = ss.accept();

            try {
                Scanner in = new Scanner(s.getInputStream());
                PrintWriter out = new PrintWriter(s.getOutputStream(), true);

                // read a line from the client and echo it back
                String line;
                while ((line = in.nextLine()) != null) 
                    out.println(line);

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                s.close();
            }
        }
    }
}

您可以尝试使用telnet localhost 1234.