java图片验证码

package com;


import java.awt.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
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;
import javax.servlet.http.HttpSession;


public class PictureCheckCode extends HttpServlet {
public PictureCheckCode() {
super();
}


public void destroy() {
super.destroy(); 
}


public void init() throws ServletException {
super.init();
}


// 获取随机颜色
public Color getRandColor(int s, int e) {
Random random = new Random();
if (s > 255) s = 255;
if (e > 255) e = 255;
int r = s + random.nextInt(e - s);//随机生成RGB颜色中的r值
int g = s + random.nextInt(e - s);//随机生成RGB颜色中的g值
int b = s + random.nextInt(e - s);//随机生成RGB颜色中的b值
return new Color(r, g, b);
}


public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "No-cache");
response.setDateHeader("Expires", 0);
// 指定生成的响应是图片
response.setContentType("image/jpeg");
int width = 86;
int height = 22;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
Graphics2D g2d = (Graphics2D) g;
Random random = new Random();
Font mFont = new Font("黑体", Font.BOLD, 17);
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, height);
g.setFont(mFont);
g.setColor(getRandColor(180, 200));
// 画随机的线条
for (int i = 0; i < 100; i++) {
int x = random.nextInt(width - 1);
int y = random.nextInt(height - 1);
int x1 = random.nextInt(6) + 1;
int y1 = random.nextInt(12) + 1;
BasicStroke bs = new BasicStroke(2f, BasicStroke.CAP_BUTT,
BasicStroke.JOIN_BEVEL);
Line2D line = new Line2D.Double(x, y, x + x1, y + y1);
g2d.setStroke(bs);
g2d.draw(line);
}
String sRand = "";
// 输出随机的验证文字
String ctmp = "";
int itmp = 0;
for (int i = 0; i < 4; i++) {
//random = new Random(new java.util.Date().getTime() + i);
switch (random.nextInt(4)) {
case 1:
itmp = random.nextInt(26) + 65; // 生成A~Z的字母
ctmp = String.valueOf((char) itmp);
break;
case 2: // 生成汉字
String[] rBase = { "0", "1", "2", "3", "4", "5", "6", "7", "8",
"9", "a", "b", "c", "d", "e", "f" };
// 生成第1位的区码
int r1 = random.nextInt(3) + 11;//生成11到14之间的随机数
String str_r1 = rBase[r1];
// 生成第2位的区码
int r2;
if (r1 == 13) {
r2 = random.nextInt(7);//生成0到7之间的随机数
} else {
r2 = random.nextInt(16);//生成0到16之间的随机数
}
String str_r2 = rBase[r2];
// 生成第1位的位码
int r3 = random.nextInt(6) + 10;//生成10到16之间的随机数
String str_r3 = rBase[r3];
// 生成第2位的位码
int r4;
if (r3 == 10) {
r4 = random.nextInt(15) + 1;//生成1到16之间的随机数
} else if (r3 == 15) {
r4 = random.nextInt(15);//生成0到15之间的随机数
} else {
r4 = random.nextInt(16);//生成0到16之间的随机数
}
String str_r4 = rBase[r4];
System.out.println(str_r1 + str_r2 + str_r3 + str_r4);
// 将生成机内码转换为汉字
byte[] bytes = new byte[2];
//将生成的区码保存到字节数组的第1个元素中
String str_r12 = str_r1 + str_r2;
int tempLow = Integer.parseInt(str_r12, 16);
bytes[0] = (byte) tempLow;
//将生成的位码保存到字节数组的第2个元素中
String str_r34 = str_r3 + str_r4;
int tempHigh = Integer.parseInt(str_r34, 16);
bytes[1] = (byte) tempHigh;

ctmp = new String(bytes);//根据字节数组生成汉字
// System.out.println("生成汉字:" + ctmp);
break;
default:
itmp = random.nextInt(10) + 48; // 生成0~9的数字
ctmp = String.valueOf((char) itmp);
break;
}
sRand += ctmp;
Color color = new Color(20 + random.nextInt(110), 20 + random
.nextInt(110), 20 + random.nextInt(110));
g.setColor(color);
/** **随机缩放文字并将文字旋转指定角度* */
// 将文字旋转指定角度
Graphics2D g2d_word = (Graphics2D) g;
AffineTransform trans = new AffineTransform();
trans.rotate(random.nextInt(45) * 3.14 / 180, 15 * i + 8, 7);
// 缩放文字
float scaleSize = random.nextFloat() +0.8f;
if (scaleSize > 1f)scaleSize = 1f;
trans.scale(scaleSize, scaleSize);
g2d_word.setTransform(trans);
/** ********************* */
g.drawString(ctmp, 15 * i + 18, 14);


}
// 将生成的验证码保存到Session中
HttpSession session = request.getSession(true);
session.setAttribute("randCheckCode", sRand);
g.dispose();
ImageIO.write(image, "JPEG", response.getOutputStream());
}


}