java.net.ConnectException : Connection refused: connect ,，客户端/服务器 TCP 套接字错误

Question

我想编写一个应用程序，学生输入他的姓名、ID、电子邮件、电话号码，然后单击保存按钮，它必须发送到服务器并保存为 file.txt,,,, 我写了这段代码，但是这个每次我在客户端运行“java.net.ConnectException:连接被拒绝:连接”时都会显示错误， 这是我的代码,,,请任何人帮助我??

服务器:

   package server;  

   import java.io.BufferedReader;  
   import java.io.DataOutputStream;  
   import java.io.FileWriter;  
   import java.io.IOException;  
   import java.io.InputStreamReader;  
   import java.io.PrintWriter;  
   import java.net.ServerSocket;  
   import java.net.Socket;  

   public class Server {  

        public static void main(String[] args) {  
        try {  
            ServerSocket service;  
            service = new ServerSocket(1309);  
            Socket server = service.accept();  
            System.out.println("server has connected");  
            InputStreamReader input = new InputStreamReader(server.getInputStream());  
            DataOutputStream output = new DataOutputStream(server.getOutputStream());  
            BufferedReader in = new BufferedReader(input);  
            String inpput = in.readLine();  
            PrintWriter f = new PrintWriter("student.txt", "UTF-8");  
            f.println(inpput);  
            f.close();  

            service.close();  

        }   catch (IOException e) {  
            System.out.println(e);  
        }  

    }  

    private static FileWriter FileWriter(String studenttxt) {  
    throw new UnsupportedOperationException("Not supported yet.");   
    }  

}  

客户端:

  package project4;  

  import java.io.BufferedReader;  
  import java.io.DataOutputStream;  
  import java.io.IOException;  
  import java.io.InputStreamReader;  
  import java.net.Socket; 

  public class p4 extends javax.swing.JFrame {  

    public p4() {  
        initComponents();}  

    private void saveActionPerformed(java.awt.event.ActionEvent evt) {                                       
        try {  


            Socket client = new Socket("localhost", 1309);  
            InputStreamReader input = new InputStreamReader(client.getInputStream());  
            DataOutputStream output = new DataOutputStream(client.getOutputStream());  
            BufferedReader in = new BufferedReader(input);  

            String n, i, e, t;  
            n = name.getText();  
            i = id.getText();  
            e = email.getText();  
            t = phone.getText();  

            String mm = n + i + e + t;  

            output.writeBytes(mm);  
            output.flush();  
            System.out.println("save");  
            output.close();  
            input.close();  
            client.close();  

        } catch (IOException o) {  
            System.out.println(o);  

        }}     
 public static void main(String args[]) {  
        p4 n = new p4();  
        n.saveActionPerformed(null);  
        java.awt.EventQueue.invokeLater(new Runnable() {  
            public void run() {  
                new p4().setVisible(true);  
            }  
        });  
   }                     
    public javax.swing.JTextField email;  
    public javax.swing.JTextField id;  
    private javax.swing.JLabel jLabel1;  
    private javax.swing.JLabel jLabel2;  
    private javax.swing.JLabel jLabel3;  
    private javax.swing.JLabel jLabel4;  
    public javax.swing.JTextField name;  
    public javax.swing.JTextField phone;  
    protected javax.swing.JButton save; } 

Answer 1

代码看起来不错(尽管您会在客户端中收到 NullPointerException ，因为 name 在第 22 行左右仍然为空)。

当我在 Windows 中完成类似的程序时，问题出在防火墙上。 您是否尝试过(暂时)关闭防火墙？