JSP生成彩色验证码!-CFANZ编程社区


 
 
1. <%@ page contentType="image/jpeg" import="java.awt.*,
2. java.awt.image.*,java.util.*,javax.imageio.*"
3. <%!  
4. Color getRandColor(int fc,int bc){//给定范围获得随机颜色
5. Random random = new
6. if(fc>255) fc=255;  
7. if(bc>255) bc=255;  
8. int
9. int
10. int
11. return new
12. }  
13. %>  
14. <%  
15. //设置页面不缓存
16. response.setHeader("Pragma","No-cache");  
17. response.setHeader("Cache-Control","no-cache");  
18. response.setDateHeader("Expires", 0);  
19.   
20. // 在内存中创建图象
21. int width=60, height=20;  
22. BufferedImage image = new
23.   
24. // 获取图形上下文
25. Graphics g = image.getGraphics();  
26.   
27. //生成随机类
28. Random random = new
29.   
30. // 设定背景色
31. g.setColor(getRandColor(200,250));  
32. g.fillRect(0, 0, width, height);  
33.   
34. //设定字体
35. g.setFont(new Font("Times New Roman",Font.PLAIN,18));  
36.   
37. //画边框
38. //g.setColor(new Color());
39. //g.drawRect(0,0,width-1,height-1);
40.   
41. // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
42. g.setColor(getRandColor(160,200));  
43. for (int i=0;i<155;i++)  
44. {  
45. int
46. int
47. int xl = random.nextInt(12);  
48. int yl = random.nextInt(12);  
49. g.drawLine(x,y,x+xl,y+yl);  
50. }  
51.   
52. // 取随机产生的认证码(4位数字)
53. String sRand="";  
54. for (int i=0;i<4;i++){  
55. String rand=String.valueOf(random.nextInt(10));  
56. sRand+=rand;  
57. // 将认证码显示到图象中
58. g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));  
59. //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
60. g.drawString(rand,13*i+6,16);  
61. }  
62.   
63. // 将认证码存入SESSION
64. session.setAttribute("rand",sRand);  
65.   
66. // 图象生效
67. g.dispose();  
68.   
69. // 输出图象到页面
70. ImageIO.write(image, "JPEG", response.getOutputStream());  
71. %>  
72.   
73.   
74. 使用验证码图片的文件a.jsp  
75.   
76. <%@ page contentType="text/html;charset=gb2312"
77. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">  
78. <html>  
79. <head>  
80. <title>认证码输入页面</title>  
81. <meta http-equiv="Content-Type" content="text/html; charset=gb2312">  
82. <META HTTP-EQUIV="Pragma" CONTENT="no-cache">  
83. <META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">  
84. <META HTTP-EQUIV="Expires" CONTENT="0">  
85. </head>  
86. <body>  
87. <form method=post action="check.jsp">  
88. <table>  
89. <tr>  
90. <td align=left>系统产生的认证码：</td>  
91. <td><img border=0 src="image.jsp"></td>  
92. </tr>  
93. <tr>  
94. <td align=left>输入上面的认证码：</td>  
95. <td><input type=text name=rand maxlength=4 value=""></td>  
96. </tr>  
97. <tr>  
98. <td colspan=2 align=center><input type=submit value="提交检测"></td>  
99. </tr>  
100. </table>  
101. </form>  
102. </body>  
103. </html>  
104.   
105.   
106. 验证的页面check.jsp  
107.   
108. <%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage=""
109. <html>  
110. <head>  
111. <title>认证码验证页面</title>  
112. <meta http-equiv="Content-Type" content="text/html; charset=gb2312">  
113. <META HTTP-EQUIV="Pragma" CONTENT="no-cache">  
114. <META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">  
115. <META HTTP-EQUIV="Expires" CONTENT="0">  
116. </head>  
117.   
118. <body>  
119. <%  
120. String rand = (String)session.getAttribute("rand");  
121. String input = request.getParameter("rand");  
122. %>  
123. 系统产生的认证码为： <%= rand %><br>  
124. 您输入的认证码为： <%= input %><br>  
125. <br>  
126. <%  
127. if
128. %>  
129. <font color=green>输入相同，认证成功！</font>  
130. <%  
131. } else
132. %>  
133. <font color=red>输入不同，认证失败！</font>  
134. <%  
135. }  
136. %>  
137. </body>  
138. </html>