package edu.zzuli.common;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
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;
/**
* @author tianshaojie
* @date 2011-1-7
* @discription :
*/
public class VerifyCodeServlet extends HttpServlet {
private static final long serialVersionUID = -7713673953332628094L;
private Font mFont = new Font("Arial Black", Font.BOLD, 15); // 设置字体new Font("Arial Black", Font.PLAIN, 15);
private int lineWidth = 5; // 2// 干扰线的长度=1.414*lineWidth
private int width = 60; // 定义图形大小
private int height = 20; // 定义图形大小
private int count = 300;// 200
private Color getRandColor(int fc, int bc) { // 取得给定范围随机颜色
Random random = new Random();
if (fc > 255) {
fc = 255;
}
if (bc > 255) {
bc = 255;
}
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
@SuppressWarnings("unused")
private char random2Char(int random) {
char c = '0';
if (random >= 0 && random <= 9) {
c = (char) (random + 48);
} else if (random >= 10 && random <= 35) {
c = (char) (random + 55);
} else if (random >= 36 && random <= 61) {
c = (char) (random + 61);
}
return c;
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// response.reset();
// 设置页面不缓存
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/gif");
// 在内存中创建图象
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics2D g = (Graphics2D) image.getGraphics();
// 生成随机类
Random random = new Random();
// 设定背景色
g.setColor(getRandColor(200, 250)); // ---1
g.fillRect(0, 0, width, height);
// 设定字体
g.setFont(mFont);
// 画边框
g.setColor(getRandColor(0, 20)); // ---2
g.drawRect(0, 0, width - 1, height - 1);
// 随机产生干扰线，使图象中的认证码不易被其它程序探测到
for (int i = 0; i < count; i++) {
g.setColor(getRandColor(150, 200)); // ---3
int x = random.nextInt(width - lineWidth - 1) + 1; // 保证画在边框之内
int y = random.nextInt(height - lineWidth - 1) + 1;
int xl = random.nextInt(lineWidth);
int yl = random.nextInt(lineWidth);
g.drawLine(x, y, x + xl, y + yl);
}
// 取随机产生的认证码(4位数字)
String sRand = "";
for (int i = 0; i < 4; i++) {
// String rand = String.valueOf(random2Char(random.nextInt(62)));
String rand = String.valueOf(random.nextInt(10));
sRand += rand;
// 将认证码显示到图象中,调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
g.setColor(new Color(20 + random.nextInt(130), 20 + random.nextInt(130), 20 + random.nextInt(130))); // --4--50-100
g.drawString(rand, (13 * i) + 6, 16);
}
// 将认证码存入SESSION
request.getSession().setAttribute(Constants_core.RANDOM_CHECKCODE, sRand);
// System.out.println("checkcode:"+sRand);
// 图象生效
g.dispose();
// 输出图象到页面
ImageIO.write(image, "PNG", response.getOutputStream());
}
public static String randomCheckCode(HttpServletRequest request) {
Random random = new Random();
String sRand = "";
for (int i = 0; i < 4; i++) {
String rand = String.valueOf(random.nextInt(10));
sRand += rand;
}
request.getSession().setAttribute(Constants_core.RANDOM_CHECKCODE, sRand);
return sRand;
}
}