1 /*
2 * To change this template, choose Tools | Templates
3 * and open the template in the editor.
4 */
5 package com.fleming.servlet;
6
7 import java.awt.Color;
8 import java.awt.Font;
9 import java.awt.Graphics;
10 import java.awt.image.BufferedImage;
11 import java.io.IOException;
12 import java.io.PrintWriter;
13 import java.util.Random;
14 import javax.imageio.ImageIO;
15 import javax.servlet.ServletException;
16 import javax.servlet.ServletOutputStream;
17 import javax.servlet.http.HttpServlet;
18 import javax.servlet.http.HttpServletRequest;
19 import javax.servlet.http.HttpServletResponse;
20 import javax.servlet.http.HttpSession;
21
22 /**
23 *
24 * @author Fleming Start
25 */
26 public class RandomCodeImageServlet extends HttpServlet {
27
28 private final int width = 60;
29 private final int height = 20;
30 private final String charset = "1234567890abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
31
32 public RandomCodeImageServlet() {
33 super();
34 }
35
36 /**
37 * Processes requests for both HTTP
38 * <code>GET</code> and
39 * <code>POST</code> methods.
40 *
41 * @param request servlet request
42 * @param response servlet response
43 * @throws ServletException if a servlet-specific error occurs
44 * @throws IOException if an I/O error occurs
45 */
46 protected void processRequest(HttpServletRequest request, HttpServletResponse response)
47 throws ServletException, IOException {
48 response.setContentType("text/html;charset=UTF-8");
49 // PrintWriter out = response.getWriter();
50 try {
51
52 BufferedImage bufferedImage = new BufferedImage(width, height,
53 BufferedImage.TYPE_INT_RGB);
54 Graphics graphics = bufferedImage.getGraphics();
55
56 Random random = new Random();
57
58 graphics.setColor(Color.WHITE);
59 graphics.fillRect(0, 0, width, height); // 填充背景
60
61 graphics.setColor(Color.GRAY);
62 graphics.drawRect(0, 0, width - 1, height - 1); // 绘制边框
63
64 // 生成干扰线
65 graphics.setColor(new Color(169, 169, 169));
66 for (int i = 1; i <= 30; i++) {
67
68 int x = random.nextInt(width);
69 int y = random.nextInt(height);
70 int xwidth = random.nextInt(20);
71 int yheight = random.nextInt(20);
72
73 graphics.drawLine(x, y, xwidth, yheight);
74 }
75
76 Font font = new Font("Courier New", Font.BOLD, 18);
77 graphics.setFont(font);
78 int red;
79 int green;
80 int blue;
81
82 char[] codeSource = charset.toCharArray(); // 验证码源
83 int length = codeSource.length;
84
85 StringBuffer randomCode = new StringBuffer(); // 用于存储随机字符
86 for (int i = 0; i < 5; i++) {
87
88 String code = String
89 .valueOf(codeSource[random.nextInt(length)]);
90 red = random.nextInt(110);
91 green = random.nextInt(50);
92 blue = random.nextInt(50);
93 graphics.setColor(new Color(red, green, blue));
94 graphics.drawString(code, 10 * i + 8, 16);
95 randomCode.append(code);
96 }
97
98 // 将验证码字符串写入session
99 HttpSession session = request.getSession();
100 session.setAttribute("randomCode", randomCode.toString());
101 graphics.dispose();
102
103 // 禁止图像缓存
104 response.setHeader("Pragma", "no-cache");
105 response.setHeader("Cache-Control", "no-cache");
106 response.setDateHeader("Expires", 0);
107
108 response.setContentType("image/jpeg");
109 ServletOutputStream sos = response.getOutputStream();
110 ImageIO.write(bufferedImage, "jpeg", sos);
111
112 } finally {
113 // out.close();
114 }
115 }
116
117 // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
118 /**
119 * Handles the HTTP
120 * <code>GET</code> method.
121 *
122 * @param request servlet request
123 * @param response servlet response
124 * @throws ServletException if a servlet-specific error occurs
125 * @throws IOException if an I/O error occurs
126 */
127 @Override
128 protected void doGet(HttpServletRequest request, HttpServletResponse response)
129 throws ServletException, IOException {
130 processRequest(request, response);
131 }
132
133 /**
134 * Handles the HTTP
135 * <code>POST</code> method.
136 *
137 * @param request servlet request
138 * @param response servlet response
139 * @throws ServletException if a servlet-specific error occurs
140 * @throws IOException if an I/O error occurs
141 */
142 @Override
143 protected void doPost(HttpServletRequest request, HttpServletResponse response)
144 throws ServletException, IOException {
145 processRequest(request, response);
146 }
147
148 /**
149 * Returns a short description of the servlet.
150 *
151 * @return a String containing servlet description
152 */
153 @Override
154 public String getServletInfo() {
155 return "Short description";
156 }// </editor-fold>
157 }
