1 package edu.zzuli.common;
2
3 import java.awt.Color;
4 import java.awt.Font;
5 import java.awt.Graphics2D;
6 import java.awt.image.BufferedImage;
7 import java.io.IOException;
8 import java.util.Random;
9
10 import javax.imageio.ImageIO;
11 import javax.servlet.ServletException;
12 import javax.servlet.http.HttpServlet;
13 import javax.servlet.http.HttpServletRequest;
14 import javax.servlet.http.HttpServletResponse;
15
16
17 /**
18 * @author tianshaojie
19 * @date 2011-1-7
20 * @discription :
21 */
22 public class VerifyCodeServlet extends HttpServlet {
23
24 private static final long serialVersionUID = -7713673953332628094L;
25
26 private Font mFont = new Font("Arial Black", Font.BOLD, 15); // 设置字体new Font("Arial Black", Font.PLAIN, 15);
27
28 private int lineWidth = 5; // 2// 干扰线的长度=1.414*lineWidth
29
30 private int width = 60; // 定义图形大小
31
32 private int height = 20; // 定义图形大小
33
34 private int count = 300;// 200
35
36 private Color getRandColor(int fc, int bc) { // 取得给定范围随机颜色
37 Random random = new Random();
38 if (fc > 255) {
39 fc = 255;
40 }
41 if (bc > 255) {
42 bc = 255;
43 }
44 int r = fc + random.nextInt(bc - fc);
45
46 int g = fc + random.nextInt(bc - fc);
47 int b = fc + random.nextInt(bc - fc);
48 return new Color(r, g, b);
49 }
50
51 @SuppressWarnings("unused")
52 private char random2Char(int random) {
53 char c = '0';
54 if (random >= 0 && random <= 9) {
55 c = (char) (random + 48);
56 } else if (random >= 10 && random <= 35) {
57 c = (char) (random + 55);
58 } else if (random >= 36 && random <= 61) {
59 c = (char) (random + 61);
60 }
61 return c;
62 }
63
64 public void doPost(HttpServletRequest request, HttpServletResponse response)
65 throws ServletException, IOException {
66 doGet(request, response);
67 }
68
69 public void doGet(HttpServletRequest request, HttpServletResponse response)
70 throws ServletException, IOException {
71 // response.reset();
72 // 设置页面不缓存
73 response.setHeader("Pragma", "No-cache");
74 response.setHeader("Cache-Control", "no-cache");
75 response.setDateHeader("Expires", 0);
76 response.setContentType("image/gif");
77 // 在内存中创建图象
78 BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
79
80 // 获取图形上下文
81 Graphics2D g = (Graphics2D) image.getGraphics();
82 // 生成随机类
83 Random random = new Random();
84 // 设定背景色
85 g.setColor(getRandColor(200, 250)); // ---1
86 g.fillRect(0, 0, width, height);
87
88 // 设定字体
89 g.setFont(mFont);
90
91 // 画边框
92 g.setColor(getRandColor(0, 20)); // ---2
93 g.drawRect(0, 0, width - 1, height - 1);
94
95 // 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
96 for (int i = 0; i < count; i++) {
97 g.setColor(getRandColor(150, 200)); // ---3
98 int x = random.nextInt(width - lineWidth - 1) + 1; // 保证画在边框之内
99 int y = random.nextInt(height - lineWidth - 1) + 1;
100 int xl = random.nextInt(lineWidth);
101 int yl = random.nextInt(lineWidth);
102 g.drawLine(x, y, x + xl, y + yl);
103 }
104
105 // 取随机产生的认证码(4位数字)
106 String sRand = "";
107
108 for (int i = 0; i < 4; i++) {
109 // String rand = String.valueOf(random2Char(random.nextInt(62)));
110 String rand = String.valueOf(random.nextInt(10));
111 sRand += rand;
112 // 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
113 g.setColor(new Color(20 + random.nextInt(130), 20 + random.nextInt(130), 20 + random.nextInt(130))); // --4--50-100
114 g.drawString(rand, (13 * i) + 6, 16);
115 }
116 // 将认证码存入SESSION
117 request.getSession().setAttribute(Constants_core.RANDOM_CHECKCODE, sRand);
118 // System.out.println("checkcode:"+sRand);
119 // 图象生效
120 g.dispose();
121 // 输出图象到页面
122 ImageIO.write(image, "PNG", response.getOutputStream());
123 }
124
125 public static String randomCheckCode(HttpServletRequest request) {
126 Random random = new Random();
127 String sRand = "";
128 for (int i = 0; i < 4; i++) {
129 String rand = String.valueOf(random.nextInt(10));
130 sRand += rand;
131 }
132 request.getSession().setAttribute(Constants_core.RANDOM_CHECKCODE, sRand);
133 return sRand;
134 }
135
136 }
