使用JAVA生成四位随机验证码图片

使用JAVA生成四位随机验证码图片
效果：是第一位和第三位是随机数字，第二位和第四位是随机字母，图片中还有随机干扰线，这些数字，字母，干扰线的颜色均随机
package cn.itcast.web.response;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.image.BufferedImageOp;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//生成验证码图片
public class Demo1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
int WIDTH = 100;
int HIGHT = 30;
//在内在中创建一幅图片
BufferedImage image = new BufferedImage(WIDTH,HIGHT,BufferedImage.TYPE_INT_RGB); //取得一个画笔
Graphics g = image.getGraphics();
//设置字符串格式
g.setFont(new Font("黑体",Font.BOLD,24));
//画干扰线
for(int i=0;i<7;i++){
Random r = new Random();
int x1 = r.nextInt(WIDTH);
int x2 = r.nextInt(WIDTH);
int y1 = r.nextInt(HIGHT);
int y2 = r.nextInt(HIGHT);
Color color = new Color(
(new Double(Math.random() * 128)).intValue() + 128,
(new Double(Math.random() * 128)).intValue() + 128,
(new Double(Math.random() * 128)).intValue() + 128);
g.setColor(color);
g.drawLine(x1, y1, x2, y2);
}
//得到一个随机颜色
Color color = new Color(
(new Double(Math.random() * 128)).intValue() + 128, (new Double(Math.random() * 128)).intValue() + 128, (new Double(Math.random() * 128)).intValue() + 128);
g.setColor(color);
//画字符串
g.drawString(getVaule(), WIDTH/5, 2*HIGHT/3);
///flyzhouw
Color color1 = new Color(
(new Double(Math.random() * 128)).intValue() + 128, (new Double(Math.random() * 128)).intValue() + 128, (new Double(Math.random() * 128)).intValue() + 128);
g.setColor(color1);
g.drawString(getChar(), WIDTH/3, 2*HIGHT/3);
Color color2 = new Color(
(new Double(Math.random() * 128)).intValue() + 128, (new Double(Math.random() * 128)).intValue() + 128, (new Double(Math.random() * 128)).intValue() + 128);
g.setColor(color2);
g.drawString(getVaule(), WIDTH/2, 2*HIGHT/3);
Color color3 = new Color(
(new Double(Math.random() * 128)).intValue() + 128, (new Double(Math.random() * 128)).intValue() + 128, (new Double(Math.random() * 128)).intValue() + 128);
g.setColor(color3);
g.drawString(getChar(), 2*WIDTH/3, 2*HIGHT/3);
//将内存中的图片，输出浏览器
ImageIO.write(image, "JPG", response.getOutputStream()); }
private String getVaule() {
Random r = new Random();
int num = r.nextInt(10);
return num + "";
}
private String getChar()
{
Random random =new Random();
int r = 0 ;
while(true)
{
r = random.nextInt(57) + 65;
if(r>90&&r<97||r==0)continue;
break;
}
char a = (char)r; return a + "";
}
}。