servlet产生随机验证码

最新推荐文章于 2025-09-09 08:37:13 发布

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最新推荐文章于 2025-09-09 08:37:13 发布

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文章标签： java

原文链接：http://www.cnblogs.com/jsolo/archive/2012/11/05/2755944.html

本文介绍了一个简单的验证码生成和发送过程，包括设置浏览器不缓存、创建图片、设置背景色、边框、绘制干扰线以及在图片上显示随机数。

 1 package com.learn.print;
 2 
 3 
 4 import java.awt.*;
 5 import java.awt.image.BufferedImage;
 6 import java.io.*;
 7 import javax.imageio.*;
 8 import javax.servlet.*;
 9 import javax.servlet.http.*;
10 import com.sun.org.apache.commons.collections.Buffer;
11 import com.sun.org.apache.commons.digester.rss.Image;
12 
13 public class Mycheckimages extends HttpServlet {
14     
15     public static int WIDTH=160;
16     public static int HEIGHT=40;
17     public static int FONT_SIZE=30;
18 
19     @Override
20     protected void doGet(HttpServletRequest req, HttpServletResponse resp)
21             throws ServletException, IOException {
22         // TODO Auto-generated method stub
23         //1。设置游览器不缓存数据
24         resp.setHeader("Expires", "-1");
25         resp.setHeader("Cache-Control", "no-cache");
26         resp.setHeader("Pragma", "no-cache");
27         
28         //2.创建图片
29         BufferedImage image=new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);
30         Graphics2D g = (Graphics2D)image.getGraphics();
31         
32         //3.设置背景色
33         g.setColor(Color.red);
34         g.fillRect(0, 0, WIDTH, HEIGHT);
35         
36         //4.设置边框及颜色
37         g.setColor(Color.WHITE);
38         g.fillRect(1, 1, WIDTH-2,HEIGHT-2);
39         
40         //5.画干扰线
41         g.setColor(Color.black);
42         for(int i=1;i<=4;i++)
43         {
44             int x1=(int)(Math.random()*WIDTH);
45             int y1=(int)(Math.random()*HEIGHT);
46             
47             int x2=(int)(Math.random()*WIDTH);
48             int y2=(int)(Math.random()*HEIGHT);
49             
50             g.drawLine(x1, y1, x2, y2);
51         }
52         
53         //6.产生随机数，并将其写到图片中
54         String s="美国大选元方你怎么看";
55         g.setColor(Color.red);
56         g.setFont(new Font("宋体",Font.BOLD,FONT_SIZE));
57         int x=(WIDTH-4*FONT_SIZE)/2;
58         int y=(HEIGHT-FONT_SIZE);
59         for(int i=1;i<=4;i++)
60         {
61             int temp=(int)(Math.random()*10);
62             String word=s.charAt(temp)+"";
63             
64             //设置旋转度数
65             int degree=(int)(Math.random()*30);
66             g.rotate(-degree*(Math.PI/180),x,HEIGHT-y);
67             g.drawString(word, x, HEIGHT-y);
68             
69             //取消旋转
70             g.rotate(degree*(Math.PI/180),x, HEIGHT-y);    
71             x+=FONT_SIZE+3;            
72         }
73             
74         //7.将图片发送给游览器
75         resp.setContentType("image/jpeg");
76         ImageIO.write(image, "jpg", resp.getOutputStream());
77         
78         
79     }
80 
81     @Override
82     protected void doPost(HttpServletRequest req, HttpServletResponse resp)
83             throws ServletException, IOException {
84         // TODO Auto-generated method stub
85         this.doGet(req, resp);
86     }
87 
88 }