java GUI,贷款服务器

本习题来自《java语言程序设计--进阶篇》第30章，网络编程的习题。

题目描述：为一个客户端编写一个服务器。客户端向服务器发送贷款信息（年利率、贷款年限和贷款总额）。服务器计算月偿还额和总偿还额，并把它们发回给客户端。将客户端程序命名为：Exercise30_1Client，将服务器程序命名为Exercise30_1Server。

package exercise.chapter30;

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

/*
 * 贷款客户端
 * 日期：2015.5.17
 */

public class Exercise30_1Client extends JFrame {
	private JPanel center = new JPanel();
	private JPanel south = new JPanel();

	private JTextArea jta = new JTextArea(8, 10);
	private JButton jbt = new JButton("Submit");

	//创建标签和文本域
	private JLabel jlb1 = new JLabel("税率");
	private JTextField rate = new JTextField();
	private JLabel jlb2 = new JLabel("贷款年数");
	private JTextField year = new JTextField();
	private JLabel jlb3 = new JLabel("贷款总数");
	private JTextField amount = new JTextField();

	public Exercise30_1Client() {
		//设计GUI布局
		center.setLayout(new GridLayout(3, 2));
		south.setLayout(new BorderLayout());

		center.add(jlb1);
		center.add(rate);
		center.add(jlb2);
		center.add(year);
		center.add(jlb3);
		center.add(amount);

		jta.setEditable(false);
		jta.setFont(new Font("", Font.BOLD, 15));
		south.add(new JScrollPane(jta), BorderLayout.CENTER);
		south.add(jbt, BorderLayout.EAST);

		this.setLayout(new BorderLayout());
		this.add(center, BorderLayout.CENTER);
		this.add(south, BorderLayout.SOUTH);

		this.setTitle("Exercise30_1Client");
		this.setSize(400, 300);
		this.setVisible(true);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		//设计socket
		try {
			Socket socket = new Socket("localhost", 8000);
			jbt.addActionListener(new MyActionListener(socket));
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void main(String[] args) {
		new Exercise30_1Client();
	}

	private class MyActionListener implements ActionListener {
		Socket socket = null;

		public MyActionListener(Socket socket) {
			this.socket = socket;
		}

		@Override
		public void actionPerformed(ActionEvent arg0) {
			try {
				DataOutputStream output = new DataOutputStream(socket.getOutputStream());
				DataInputStream input = new DataInputStream(socket.getInputStream());
				double rateStr = Double.parseDouble(rate.getText().trim());
				double yearStr = Double.parseDouble(year.getText().trim());
				double amountStr = Double.parseDouble(amount.getText().trim());
				String message = rateStr + "@" + yearStr + "@" + amountStr;

				output.write(message.getBytes());
				output.flush();

				byte[] buf = new byte[1024];
				int len = 0;

				//文本域清零
				rate.setText("");
				year.setText("");
				amount.setText("");

				double amount = input.readDouble();
				//向jta中追加数据
				jta.append("税率: " + rateStr + ", 贷款年数：" + yearStr + ", 贷款总额: " +
						amountStr + " ,偿还总额：" + amount);
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
}

import javax.swing.*;
import java.awt.*;
import java.io.*;
import java.net.*;
import java.util.*;
/*
 *功能：贷款服务器
 *日期：2015.5.17
 */

public class Exercise30_1Server extends JFrame {
	private JTextArea jta = new JTextArea();

	public Exercise30_1Server() {
		this.setTitle("Exercise30_1Server");
		this.setSize(400, 300);
		this.setResizable(false);
		this.setVisible(true);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		jta.setFont(new Font("Font.ITALIC",Font.PLAIN, 15));
		jta.setEditable(false);
		this.setLayout(new BorderLayout());
		this.add(new JScrollPane(jta), BorderLayout.CENTER);

		jta.append("Server started at " + new Date() + '\n');

		try {
			ServerSocket ss = new ServerSocket(8000);
			Socket socket = ss.accept();

			//获取InetAddress类
			InetAddress inetAddress = socket.getInetAddress();
			jta.append("Client's hostname is: " + inetAddress.getHostName());
			jta.append("\n");
			jta.append("Client's ip is: " + inetAddress.getHostAddress());
			jta.append("\n");

			DataInputStream input = new DataInputStream(socket.getInputStream());
			DataOutputStream output = new DataOutputStream(socket.getOutputStream());
			byte[] buf = new byte[1024];
			int len = 0;
			while((len = input.read(buf)) != -1) {
				double amount = getAmount(new String(buf, 0, len));
				output.writeDouble(amount);

				jta.append(new String(buf, 0, len));
				jta.append("\n");
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	private static double getAmount(String str) {
		String[] str1 = str.split("@");

		double rate = Double.parseDouble(str1[0]);
		double years = Double.parseDouble(str1[1]);
		double amount = Double.parseDouble(str1[2]);

		return rate * years * amount + amount;
	}

	public static void main(String[] args) {
		JFrame frame = new Exercise30_1Server();
	}
}