Jsp servlet验证码工具类分享（java编写jsp验证码）学到了

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;

public class VeriyCodeUtils {

public static String newVeriyCode(OutputStream output)
{
int width=90;
int height=40;
int codeCount=5;
char[] codeSequence={ ‘A’, ‘B’, ‘C’, ‘D’, ‘E’, ‘F’, ‘G’, ‘H’, ‘I’, ‘J’,
‘K’, ‘L’, ‘M’, ‘N’, ‘O’, ‘P’, ‘Q’, ‘R’, ‘S’, ‘T’, ‘U’, ‘V’, ‘W’,
‘X’, ‘Y’, ‘Z’, ‘0’, ‘1’, ‘2’, ‘3’, ‘4’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’ };

//创建图像对象,8位RGB
BufferedImage buffered=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

//通过Crapahices来绘制图像到BufferedImage中
Graphics2D gra=buffered.createGraphics();

//设置图片背景：白色
gra.setColor(Color.WHITE);
gra.fillRect(0, 0, width, height);

//设置字体,字体大小根据图片高度决定
gra.setFont(new Font(“Fixedsys”,Font.PLAIN,height-2));

//设置边框：黑色,1cm
gra.setColor(Color.BLACK);
gra.drawRect(0, 0, width-1, height-1);

//生成10条黑色干扰线
gra.setColor(Color.BLACK);
Random ran=new Random();
for(int i=0; i < 70;i++)
{
int x=ran.nextInt(255);
int y=ran.nextInt(255);
int x1=ran.nextInt(255);
int y1=ran.nextInt(255);
gra.drawLine(x, y,x+x1, y+y1);//画直线
}
//生成验证码
StringBuffer sb=new StringBuffer();
int r=0,g=0,b=0;
for(int i=0; i < codeCount; i++)
{
String strRand=String.valueOf(codeSequence[ran.nextInt(codeSequence.length)]);
//对每位验证码都生成不同的颜色，增加识别系统难度
r=ran.nextInt(255);
g=ran.nextInt(255);
b=ran.nextInt(255);
gra.setColor(new Color(r, g, b));
gra.drawString(strRand, (i+1)*13, height-4);
sb.append(strRand);
}
try {
ImageIO.write(buffered, “jpeg”, output);
} catch (Exception e) {
throw new RuntimeException(e);
}

return sb.toString();
}
}