图形程序设计

1.绘制几何图形

package draw;

import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;

public class DrawTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() ->
         {
            var frame = new DrawFrame();
            frame.setTitle("DrawTest");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
         });
   }
}

/**
 * A frame that contains a panel with drawings.
 */
class DrawFrame extends JFrame
{
   public DrawFrame()
   {      
      add(new DrawComponent());
      pack();
   }
}

/**
 * A component that displays rectangles and ellipses.
 */
class DrawComponent extends JComponent
{
   private static final int DEFAULT_WIDTH = 400;
   private static final int DEFAULT_HEIGHT = 400;

   public void paintComponent(Graphics g)
   {
      var g2 = (Graphics2D) g;

      // draw a rectangle

      double leftX = 100;
      double topY = 100;
      double width = 200;
      double height = 150;

      var rect = new Rectangle2D.Double(leftX, topY, width, height);
      g2.draw(rect);

      // draw the enclosed ellipse

      var ellipse = new Ellipse2D.Double();
      ellipse.setFrame(rect);
      g2.draw(ellipse);

      // draw a diagonal line

      g2.draw(new Line2D.Double(leftX, topY, leftX + width, topY + height));

      // draw a circle with the same center

      double centerX = rect.getCenterX();
      double centerY = rect.getCenterY();
      double radius = 150;

      var circle = new Ellipse2D.Double();
      circle.setFrameFromCenter(centerX, centerY, centerX + radius, centerY + radius);
      g2.draw(circle);
   }
   
   public Dimension getPreferredSize()
   {
      return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT);
   }
}

2.事件响应

编写图形界面程序，接受用户输入的5个浮点数据和一个文件目录名，将这五个数据保存在该文件中。

package test;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;

import javax.swing.*;
import java.io.*;
import java.util.Arrays;
@SuppressWarnings("unused")
public class shiyan3 {	
	public static void  main(String[] args) {
		shiyan3Frame s3 = new shiyan3Frame();
		s3.setVisible(true);
	}
}

@SuppressWarnings("serial")
class shiyan3Frame extends JFrame{
	private JLabel lbl1;
	private JLabel lbl2;
	private JTextField text1;
	private JTextField text2;
	private JTextField text3;
	private JTextField text4;
	private JTextField text5;
	private JTextField Text;
	private JButton btn1;
	private JButton btn2;
	private String str;
	shiyan3Frame(){
		setTitle("实验3");
		setSize(600, 400);
		this.setLayout(new GridLayout(10,1));
		text1 = new JTextField();
		text2 = new JTextField();
		text3 = new JTextField();
		text4 = new JTextField();
		text5 = new JTextField();
		Text = new JTextField();
		lbl1 = new JLabel("输入文件名：");
		lbl2 = new JLabel("输入数字：");
		btn1 = new JButton("打开文件");
		btn2 = new JButton("发送数字");
		btn1.addActionListener(new ActionListener(){  //添加监听器,单击打开文件的按钮后产生事件
			public void actionPerformed(ActionEvent e){
				str = Text.getText();
				System.out.println(str);
			}
		});
		btn2.addActionListener(new ActionListener(){  //添加监听器,单击打开文件的按钮后产生事件
			@SuppressWarnings("deprecation")
			public void actionPerformed(ActionEvent e){
				String s1 = text1.getText()+" ";	
				String s2 = text2.getText()+" ";
				String s3 = text3.getText()+" ";
				String s4 = text4.getText()+" ";
				String s5 = text5.getText();
				float[] f = new float[5];
				try {
//					System.out.println(str);
					System.out.println(s1+s2+s3+s4+s5);
					File outFile = new File(str);
					FileOutputStream fos = new FileOutputStream(outFile);
					DataOutputStream dos = new DataOutputStream(fos);
					dos.writeBytes(s1);
					dos.writeBytes(s2);
					dos.writeBytes(s3);
					dos.writeBytes(s4);
					dos.writeBytes(s5);
					dos.writeBytes("
");
					dos.close();
					fos.close();
					
					File inFile = new File(str);
					FileInputStream fis = new FileInputStream(inFile);
					DataInputStream dis = new DataInputStream(fis);
					String str1,Str="";
					while((str1 = dis.readLine())!=null) {
						Str += str1;
					}
					String[] arr = Str.split(" ");
					dis.close();
					fis.close();
					for (int i = 0; i <= 4; i++) {
						f[i] = Float.parseFloat(arr[i]);
					}
					Arrays.sort(f);
					s1 = f[4]+" ";
					s2 = f[3]+" ";
					s3 = f[2]+" ";
					s4 = f[1]+" ";
					s5 = f[0]+"";
					
					outFile = new File(str);
					fos = new FileOutputStream(outFile,true);//加上true后表明是追加，不然就一直会覆盖
					dos = new DataOutputStream(fos);
					dos.writeBytes(s1);
					dos.writeBytes(s2);
					dos.writeBytes(s3);
					dos.writeBytes(s4);
					dos.writeBytes(s5);
					dos.close();
					fos.close();
				}catch(FileNotFoundException e1) {
					System.out.println("FileStream"+e1);
				}catch(IOException e2) {
					System.err.println("FileStream"+e2);
				}
			}
		});
		
		
		add(lbl1);
		add(Text);
		add(btn1);
		add(lbl2);
		add(text1);
		add(text2);
		add(text3);
		add(text4);
		add(text5);
		add(btn2);
	}
}