Java第三次实验作业。
一、
开发一个加、减、乘、除四则运算器。用户界面如下图：
laCkAx.png
package hw5;
import java.awt.*;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javafx.event.ActionEvent;
public class jsq extends JFrame {
private JPanel contentPane;
private JTextField textField;
private JTextField textField_1;
private JTextField textField_2;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
jsq frame = new jsq();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public jsq() {
setFont(new Font("幼圆", Font.BOLD, 20));
setForeground(new Color(153, 50, 204));
setTitle("\u8BA1\u7B97\u5668");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
textField = new JTextField();
textField.setBounds(0, 0, 432, 56);
contentPane.add(textField);
textField.setColumns(10);
textField_1 = new JTextField();
textField_1.setBounds(0, 67, 432, 56);
contentPane.add(textField_1);
textField_1.setColumns(10);
JButton btnNewButton = new JButton("+");
btnNewButton.setFont(new Font("幼圆", Font.BOLD, 16));
btnNewButton.setForeground(new Color(50, 205, 50));
btnNewButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(java.awt.event.ActionEvent e) {
// TODO Auto-generated method stub
double x = Double.parseDouble(textField.getText());
double y = Double.parseDouble(textField_1.getText());
double z = x+y;
if(z - (int)z <= 0.00001) textField_2.setText(Integer.toString((int)z));
else textField_2.setText(Double.toString(z));
}
});
btnNewButton.setBounds(0, 122, 103, 54);
contentPane.add(btnNewButton);
JButton btnNewButton_1 = new JButton("-");
btnNewButton_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
}
@Override
public void actionPerformed(java.awt.event.ActionEvent e) {
// TODO Auto-generated method stub
double x = Double.parseDouble(textField.getText());
double y = Double.parseDouble(textField_1.getText());
double z = x-y;
if(z - (int)z <= 0.00001) textField_2.setText(Integer.toString((int)z));
else textField_2.setText(Double.toString(z));
}
});
btnNewButton_1.setFont(new Font("幼圆", Font.BOLD, 20));
btnNewButton_1.setForeground(new Color(255, 69, 0));
btnNewButton_1.setBounds(115, 122, 103, 54);
contentPane.add(btnNewButton_1);
JButton btnNewButton_2 = new JButton("*");
btnNewButton_2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
}
@Override
public void actionPerformed(java.awt.event.ActionEvent e) {
// TODO Auto-generated method stub
double x = Double.parseDouble(textField.getText());
double y = Double.parseDouble(textField_1.getText());
double z = x*y;
if(z - (int)z <= 0.00001) textField_2.setText(Integer.toString((int)z));
else textField_2.setText(Double.toString(z));
}
});
btnNewButton_2.setFont(new Font("幼圆", Font.BOLD, 20));
btnNewButton_2.setForeground(new Color(255, 215, 0));
btnNewButton_2.setBounds(218, 122, 103, 54);
contentPane.add(btnNewButton_2);
JButton btnNewButton_3 = new JButton("/");
btnNewButton_3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
}
@Override
public void actionPerformed(java.awt.event.ActionEvent e) {
// TODO Auto-generated method stub
double x = Double.parseDouble(textField.getText());
double y = Double.parseDouble(textField_1.getText());
double z = x/y;
if(z - (int)z <= 0.00001) textField_2.setText(Integer.toString((int)z));
else textField_2.setText(Double.toString(z));
}
});
btnNewButton_3.setFont(new Font("幼圆", Font.BOLD, 20));
btnNewButton_3.setForeground(new Color(0, 191, 255));
btnNewButton_3.setBounds(329, 122, 103, 54);
contentPane.add(btnNewButton_3);
textField_2 = new JTextField();
textField_2.setBounds(0, 187, 442, 58);
contentPane.add(textField_2);
textField_2.setColumns(10);
}
}
laCr5V.png
二、
编写一个程序，实现文件内容拷贝，具体过程如下：
1) 建一文件myfile1.txt，写入内容“I am a student.”；
2) 打开文件myfile1.txt，读出内容放入字符数组中；
3) 再建一文件myfile2.txt，将字符数组中内容写入；
4) 打开文件myfile2.txt，读出内容输出到屏幕。
package hw5;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class shi_1 {
public static void main(String[] args)
{
String str=null;
String str1=null;
String name_1="F:/myfile1.txt";
String name_2="F:/myfile2.txt";
FileWriter w1=null;
try {
w1=new FileWriter(name_1,true);
w1.write("I am a student.");
w1.close();
System.out.println("myfile1.txt写入成功");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
FileReader r1=null;
BufferedReader br1=null;
try {
r1=new FileReader(name_1);
br1=new BufferedReader(r1);
try {
str=br1.readLine();
//System.out.println(str);
br1.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
FileWriter w2=null;
BufferedWriter bw2=null;
try {
w2=new FileWriter(name_2,true);
bw2=new BufferedWriter(w2);
bw2.write(str);
bw2.flush();
w2.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
FileReader r2=null;
BufferedReader br2=null;
try {
r2=new FileReader(name_2);
br2=new BufferedReader(r2);
try {
str1=br2.readLine();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(str1);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
laCI56.png
三、
编写一个窗口程序，界面如下图，窗口FlowLayout布局，宽240，高200；文本框宽10，文本区大小为5行25列。
要求实现下列功能：
1) 点击“打开文件”，则弹出打开文件对话框，可从(D盘根目录)中选择一个字符文件，然后将选择的文件名称显示在文本框中；
2) 点击“显示文件内容”，则读出打开的文件的内容，并将读取的内容显示在文本区中；
package hw5;
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.JTextArea;
import javax.swing.JList;
import javax.swing.JComboBox;
import javax.swing.JFileChooser;
import java.awt.Panel;
import java.awt.ScrollPane;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.awt.event.ActionEvent;
public class wenjian extends JFrame {
private JPanel contentPane;
private JTextField textField;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
wenjian frame = new wenjian();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public wenjian() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JButton btnNewButton = new JButton("\u6253\u5F00\u6587\u4EF6");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
JFileChooser chooser = new JFileChooser();
chooser.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
chooser.showDialog(new JLabel(), "选择");
File file = chooser.getSelectedFile();
textField.setText(file.getAbsoluteFile().toString());
}
});
btnNewButton.setBounds(23, 11, 129, 42);
contentPane.add(btnNewButton);
textField = new JTextField();
textField.setBounds(199, 21, 198, 22);
contentPane.add(textField);
textField.setColumns(10);
JTextArea textArea = new JTextArea();
textArea.setBounds(33, 68, 346, 112);
contentPane.add(textArea);
JButton btnNewButton_1 = new JButton("\u663E\u793A\u6587\u4EF6\u5185\u5BB9");
btnNewButton_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
FileReader fr=new FileReader(textField.getText());
BufferedReader br=new BufferedReader(fr);
try {
textArea.setText(br.readLine());
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});
btnNewButton_1.setBounds(124, 192, 167, 41);
contentPane.add(btnNewButton_1);
}
}
laPniV.png
