Java Servlet 写的随机验证码图片 

  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 }

 

posted @ 2013-03-13 15:27  小方F  阅读(322)  评论(0)    收藏  举报