package ex30;

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Client extends JFrame{
    // Text field for receiving radius
    private JTextField jtf = new JTextField();
    
    // Text area to display contents
    private JTextArea jta = new JTextArea();
    
    // IO streams
    private DataOutputStream toServer;
    private DataInputStream fromServer;
    
    public static void main(String[] args) {
        // TODO 自动生成方法存根
        new Client();
    }
    
    public Client(){
        // Panel p to hold the label and text field
        JPanel p = new JPanel();
        p.setLayout(new BorderLayout());
        p.add(new JLabel("Enter radius"), BorderLayout.WEST);
        p.add(jtf, BorderLayout.CENTER);
        jtf.setHorizontalAlignment(JTextField.RIGHT);
        
        setLayout(new BorderLayout());
        add(p, BorderLayout.NORTH);
        add(new JScrollPane(jta), BorderLayout.CENTER);
        
        jtf.addActionListener(new TextFieldListener());
        
        setTitle("Client");
        setSize(500, 300);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);  // It is necessary to show the frame here!
        
        try{
            // Create a socket to connect to the server
            Socket socket = new Socket("localhost", 8000);
            // Socket socket = new Socket("130.254.204.36", 8000);
            // Socket socket = new Socket("drake.Armstrong.edu", 8000);
            
            // Create an input stream to receive data from the server
            toServer =
                new DataOutputStream(socket.getOutputStream());
        }
        catch(IOException ex){
            jta.append(ex.toString() + '\n');
        }
    }
    
    private class TextFieldListener implements ActionListener{
        public void actionPerformed(ActionEvent e){
            try{
                // Get the radius from the text field
                double radius = Double.parseDouble(jtf.getText().trim());
                
                // Send the radius to the server
                toServer.writeDouble(radius);
                toServer.flush();
                
                // Get area from the server
                double area = fromServer.readDouble();  //这一行为什么会报异常，但程序还能运行
                
                // Display to the text area
                jta.append("Radius is " + radius + "\n");
                jta.append("Area received from the server is "
                        + area + '\n');
            }
            catch(IOException ex){
                System.err.println(ex);
            }
        }
    }

}

package ex30;

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Client extends JFrame{
    // Text field for receiving radius
    private JTextField jtf = new JTextField();
    
    // Text area to display contents
    private JTextArea jta = new JTextArea();
    
    // IO streams
    private DataOutputStream toServer;
    private DataInputStream fromServer;
    
    public static void main(String[] args) {
        // TODO 自动生成方法存根
        new Client();
    }
    
    public Client(){
        // Panel p to hold the label and text field
        JPanel p = new JPanel();
        p.setLayout(new BorderLayout());
        p.add(new JLabel("Enter radius"), BorderLayout.WEST);
        p.add(jtf, BorderLayout.CENTER);
        jtf.setHorizontalAlignment(JTextField.RIGHT);
        
        setLayout(new BorderLayout());
        add(p, BorderLayout.NORTH);
        add(new JScrollPane(jta), BorderLayout.CENTER);
        
        jtf.addActionListener(new TextFieldListener());
        
        setTitle("Client");
        setSize(500, 300);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);  // It is necessary to show the frame here!
        
        try{
            // Create a socket to connect to the server
            Socket socket = new Socket("localhost", 8000);
            // Socket socket = new Socket("130.254.204.36", 8000);
            // Socket socket = new Socket("drake.Armstrong.edu", 8000);
            
            // Create an input stream to receive data from the server
            toServer =
                new DataOutputStream(socket.getOutputStream());
        }
        catch(IOException ex){
            jta.append(ex.toString() + '\n');
        }
    }
    
    private class TextFieldListener implements ActionListener{
        public void actionPerformed(ActionEvent e){
            try{
                // Get the radius from the text field
                double radius = Double.parseDouble(jtf.getText().trim());
                
                // Send the radius to the server
                toServer.writeDouble(radius);
                toServer.flush();
                
                // Get area from the server
                double area = fromServer.readDouble();  //这一行为什么会报异常，但程序还能运行
                
                // Display to the text area
                jta.append("Radius is " + radius + "\n");
                jta.append("Area received from the server is "
                        + area + '\n');
            }
            catch(IOException ex){
                System.err.println(ex);
            }
        }
    }

}