Copy Code code as follows:
<%@ page language= "java" contenttype= "text/html; Charset=utf-8 "
pageencoding= "UTF-8"%>
<meta http-equiv= "Content-type" content= "text/html; Charset=utf-8 ">
<title> Landing Page </title>
<script type= "Text/javascript" >
function Refresh () {
LOGINFORM.IMAGE.SRC = "creatimage.jsp";
}
</script>
<body>
<form action= "" method = "Post" name= "LoginForm" >
<label> account: <input name= "username" type= "text"/></label><br>
<label> Password: <input name= "password" type= "password"/></label><br>
<label> Verification Code: <input name= "code" type= "text"/></label>
<!--the validation code as a picture processing-->
<input type= "Submit" value= "Landing"/>
</form>
</body>
Copy Code code as follows:
<% @page import= "Java.util.Random"%>
<% @page import= "Java.awt.Graphics"%>
<% @page import= "javax.imageio.*"%>
<% @page import= "java.awt.*"%>
<% @page import= "Java.awt.image.BufferedImage"%>
<%@ page language= "java" contenttype= "text/html; Charset=utf-8 "
pageencoding= "UTF-8"%>
<%
Final char[] str = {' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ', ' 7 ', ' 8 ', ' 9 ',
' A ', ' B ', ' C ', ' d ', ' e ', ' f ', ' g ', ' h ', ' I ', ' j ', ' K ', ' l ', ' m ', ' n ', ' o ', ' P ', ' Q ',
' R ', ' s ', ' t ', ' u ', ' V ', ' w ', ' x ', ' y ', ' z ', ' A ', ' B ', ' C ', ' D ', ' E ', ' F ', ' G ', ' H ',
' I ', ' J ', ' K ', ' L ', ' M ', ' N ', ' O ', ' P ', ' Q ', ' R ', ' S ', ' T ', ' U ', ' V ', ' W ', ' X ', ' Y ', ' Z '};
int width=100,height=60;
BufferedImage bi = new BufferedImage (Width,height,
BUFFEREDIMAGE.TYPE_INT_RGB);
Graphics g = bi.getgraphics ();
G.setcolor (New Color (200,200,200));
G.fillrect (0, 0, width, height);
Random rnd = new Random ();
StringBuffer sb = new StringBuffer ("");
Produces a four-digit alphanumeric verification code, and the color of each number is immediately
for (int i=0; i<4; i++) {
int num = Rnd.nextint (str.length);
Color c = new Color (rnd.nextint (256),
Rnd.nextint (256), Rnd.nextint (256));
G.setcolor (c);
G.setfont (New Font ("", Font.bold+font.italic, 20));
g.DrawString (str[num]+ "", 10, 17);
Sb.append (Str[num]);
}
Jamming line
for (int i=0; i<10; i++) {
Color c = new Color (rnd.nextint (256),
Rnd.nextint (256), Rnd.nextint (256));
G.setcolor (c);
G.drawline (Rnd.nextint (width), rnd.nextint (height),
Rnd.nextint (width), rnd.nextint (height));
}
string s = new string (SB);
/*
If four digits are generated, then Nextint (8999) + 1000;
String.valueof then converts to string
*/
Verification code stored in the session, to facilitate the landing in the school check page comparison
Session.setattribute ("image", s);
Output to Page
Imageio.write (BI, "JPEG", Response.getoutputstream ());
/*
What's the effect of adding the following two sentences?
Otherwise reported abnormal: Java.lang.IllegalStateException:getOutputStream ()
has already been called for this response
Whatever the reason.
*/
Out.clear ();
out = Pagecontext.pushbody ();
%>
<meta http-equiv= "Content-type" content= "text/html; Charset=utf-8 ">
<title> Picture Generation </title>
<body>
</body>
