JAVA验证码



package Pretic;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Panel;
import java.util.Random;

import javax.swing.JFrame;

public class AwtDrawing extends JFrame{
final Panel panel = new MyPanel();
public AwtDrawing(){
this.add(panel);
this.setSize(200, 100);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
public static void main(String args[]){

new AwtDrawing();
//frame.addWindowListener(new MyWindowListener());
}
}

//验证码显示（随机数）
class MyPanel extends Panel {
public void paint(Graphics g) {
int width = 160;
int height = 40;
g.setColor(Color.green);
g.fillRect(0,0, width, height);
g.setColor(Color.lightGray);
g.drawRect(0, 0, width-1, height-1);

Random r = new Random();
for(int i=0; i<100; i++){
int x = r.nextInt(width) - 2;
int y = r.nextInt(height) - 2;
g.drawOval(x, y, 2,2 );
}

g.setFont(new Font("黑体",Font.BOLD,30));
g.setColor(Color.BLUE);

char chars[] = ("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();
StringBuilder sb = new StringBuilder();
for(int i=0; i<4; i++){
int pos = r.nextInt(chars.length);
char c = chars[pos];
sb.append(c+" ");
}
g.drawString(sb.toString(), 20, 30);
}
}