servlet生成验证码图片

Color=#cccccc cellSpacing=0 cellPadding=1 width="80%" align=center bgColor=#ffffff border=1 heihgt="">   
001 package com.rolia.learning.learningweb.validationcode;
002
003 /*
004  * 创建日期 2006-7-23
005  *
006  * TODO 要更改此生成的文件的模板，请转至
007  * 窗口 － 首选项 － Java － 代码样式 － 代码模板
008  * 参数：
009  * count:验证码的字符个数
010  * width:验证码图片宽度
011  * height:验证码图片高度
012  * type:类型 0-纯数字 1-纯大写字母 2-数字和大学字母混合
013  * 功能：生成验证码图片，将验证码保存进session里
014  */
015 import java.io.IOException;
016
017 import javax.servlet.ServletConfig;
018 import javax.servlet.ServletException;
019 import javax.servlet.http.HttpServlet;
020 import javax.servlet.http.HttpServletRequest;
021 import javax.servlet.http.HttpServletResponse;
022
023 import java.awt.*;
024 import java.awt.image.*;
025 import java.util.*;
026 import javax.imageio.*;
027 /**
028  * @author Rolia
029  *
030  * TODO 要更改此生成的类型注释的模板，请转至
031  * 窗口 － 首选项 － Java － 代码样式 － 代码模板
032  */
033 public class ValidationCodeServlet extends HttpServlet {
034
035     /**
036    *
037    */
038   private static final long serialVersionUID = 1L;
039   private final int TYPE_NUMBER = 0;
040     private final int TYPE_LETTER = 1;
041     private final int TYPE_MULTIPLE = 2;
042     private int width;
043     private int height;
044     private int count;
045     private int type;
046     private String  validate_code;
047     private Random random;
048     private Font font;
049     private int line;
050
051     @Override
052   public void init(ServletConfig config) throws ServletException {
053         super.init(config);
054         width = 150;
055         height = 50;
056         count = 4;
057         type = TYPE_NUMBER;
058         random = new Random();
059         line = 200;
060     }
061
062     @Override
063   protected void doGet(HttpServletRequest request,
064             HttpServletResponse response) throws ServletException, IOException {
065         response.setHeader("Pragma","No-cache");
066         response.setHeader("Cache-Control","no-cache");
067         response.setDateHeader("Expires", 0);
068         response.setContentType("image.jpeg");
069
070         String reqCount = request.getParameter("count");
071         String reqWidth = request.getParameter("width");
072         String reqHeight = request.getParameter("height");
073         String reqType = request.getParameter("type");
074
075         if(reqCount!=null && reqCount!="")this.count = Integer.parseInt(reqCount);
076         if(reqWidth!=null && reqWidth!="")this.width = Integer.parseInt(reqWidth);
077         if(reqHeight!=null && reqHeight!="")this.height = Integer.parseInt(reqHeight);
078         if(reqType!=null && reqType!="")this.type = Integer.parseInt(reqType);
079
080         font = new Font("Courier New",Font.BOLD,width/count);
081
082         BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
083
084         Graphics g = image.getGraphics();
085
086         g.setColor(getRandColor(200,250));
087         g.fillRect(0, 0, width, height);
088
089         g.setColor(getRandColor(160,200));
090         for (int i=0;i<line;i++){
091             int x = random.nextInt(width);
092             int y = random.nextInt(height);
093             int xl = random.nextInt(12);
094             int yl = random.nextInt(12);
095             g.drawLine(x,y,x+xl,y+yl);
096         }
097
098         g.setFont(font);
099         validate_code = getValidateCode(count,type);
100         request.getSession().setAttribute("validate_code",validate_code);
101         for (int i=0;i<count;i++){
102             g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//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
103             int x = (int)(width/count)*i;
104             int y = (int)((height+font.getSize())/2)-5;
105             g.drawString(String.valueOf(validate_code.charAt(i)),x,y);
106         }
107
108         g.dispose();
109         ImageIO.write(image, "JPEG", response.getOutputStream());
110     }
111
112     @Override
113   protected void doPost(HttpServletRequest request,
114             HttpServletResponse response) throws ServletException, IOException {
115         doGet(request, response);
116     }
117
118     private Color getRandColor(int from,int to){
119         Random random = new Random();
120         if(to>255) from=255;
121         if(to>255) to=255;
122         int rang = Math.abs(to - from);
123         int r=from+random.nextInt(rang);
124         int g=from+random.nextInt(rang);
125         int b=from+random.nextInt(rang);
126         return new Color(r,g,b);
127     }
128
129     private String getValidateCode(int size,int type){
130         StringBuffer validate_code = new StringBuffer();
131         for(int i = 0; i < size; i++){
132             validate_code.append(getOneChar(type));
133         }
134         return validate_code.toString();
135     }
136     private String getOneChar(int type){
137         String result = null;
138         switch(type){
139             case TYPE_NUMBER:
140                 result = String.valueOf(random.nextInt(10));
141                 break;
142
143             case TYPE_LETTER:
144                 result = String.valueOf((char)(random.nextInt(26)+65));
145                 break;
146
147             case TYPE_MULTIPLE:
148                 if(random.nextBoolean()){
149                     result = String.valueOf(random.nextInt(10));
150                 }else{
151                     result = String.valueOf((char)(random.nextInt(26)+65));
152                 }
153                 break;
154             default:
155                 result=null;
156                 break;
157         }
158         if(result==null)throw new NullPointerException("获取验证码出错");
159         return result;
160     }
161 }
 

 
web.xml

 <!-- 生成图片验证码 -->
  <servlet>
   <servlet-name>validationcodeServlet</servlet-name>
   <servlet-class>com.rolia.learning.learningweb.validationcode.ValidationCodeServlet</servlet-class>
  </servlet>
<servlet-mapping>
   <servlet-name>validationcodeServlet</servlet-name>
   <url-pattern>/ValidateCodeServlet</url-pattern>
  </servlet-mapping>
validationcode_show.jsp

<!DOCTYPE HTML PUBLIC "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
<title></title>
</head>
<body bgcolor="#FFFFFF">
<form action="validationcode_heck.jsp" method=post>
<table align=center>
<tr><td>
请输入验证码：<input type='text' name='validate_code' size=20>
</td><td>
<img src="ValidateCodeServlet" width=150 height=50>
</td></tr>
<tr><td>
<input type="submit" value="提交">
</td><td>
<input type="reset" value="重填">
</td></tr>
</table>
</form>
</body>
</html>

validationcode_check.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
<title>Lomboz JSP</title>
</head>
<body bgcolor="#FFFFFF">

<%
String session_validate_code = (session.getAttribute("validate_code")).toString();
if(session_validate_code==null)System.out.println("validate code has not set");
else{
 String request_code = request.getParameter("validate_code");
 if(request_code==null)out.println("未输入");
 else{
  if(request_code.equalsIgnoreCase(session_validate_code))out.println("匹配");
  else out.println("不匹配");
 }
}
%>
</body>
</html>