image.jsp------------------------------A JSP page that generates random CAPTCHA pictures
The code is as follows:
Copy Code code as follows:
<%@ page contenttype= "image/jpeg" import= "java.awt.*,
Java.awt.image.*,java.util.*,javax.imageio.* "%>
<%!
Color getrandcolor (int fc,int BC)
{
Random Random = new Random ();
if (fc>255) fc=255;
if (bc>255) bc=255;
int R=fc+random.nextint (BC-FC);
int G=fc+random.nextint (BC-FC);
int B=fc+random.nextint (BC-FC);
return new Color (R,G,B);
}
%>
<%
Out.clear ()//This sentence for the resin server, if it is tomacat can not this sentence
Response.setheader ("Pragma", "No-cache");
Response.setheader ("Cache-control", "No-cache");
Response.setdateheader ("Expires", 0);
int width=60, height=20;
BufferedImage image = new BufferedImage (width, height, bufferedimage.type_int_rgb);
Graphics g = image.getgraphics ();
Random Random = new Random ();
G.setcolor (Getrandcolor (200,250));
G.fillrect (0, 0, width, height);
G.setfont (New Font ("Times New Roman", font.plain,18));
G.setcolor (Getrandcolor (160,200));
for (int i=0;i<155;i++)
{
int x = random.nextint (width);
int y = random.nextint (height);
int xl = Random.nextint (12);
int yl = Random.nextint (12);
G.drawline (X,y,x+xl,y+yl);
}
String srand= "";
for (int i=0;i<4;i++) {
String rand=string.valueof (Random.nextint (10));
Srand+=rand;
G.setcolor (New Color (20+random.nextint), 20+random.nextint (a), 20+random.nextint (110));
g.DrawString (rand,13*i+6,16);
}
Save authentication Code in session
Session.setattribute ("Rand", SRand);
G.dispose ();
Imageio.write (Image, "JPEG", Response.getoutputstream ());
%>
logic.jsp--------------------------------Landing page, provide input verification code here and then submit and verify
The code is as follows:
Copy Code code as follows:
<%@ page contenttype= "TEXT/HTML;CHARSET=GBK"%>
<%@ page language= "java" import= "java.sql.*" errorpage= ""%>
<meta http-equiv= "Content-type" content= "text/html; charset=gb2312 ">
<title> User Login </title>
<script language= "JavaScript" >
function LoadImage () {
document.getElementById ("Randimage"). src = "image.jsp?" +math.random ();
}
</script>
<body>
<table width= "256" border= "0" cellpadding= "0" cellspacing= "0" >
<!--dwlayouttable-->
<form action= "validate.jsp" method= "post" name= "LoginForm" >
<tr>
<TD width= "118" height= "valign=" Middle "center" align= ><input "text" type= "Rand" Name= "size=" Td>
<TD width= "138" valign= "Middle" align= "center" ></td>
</tr>
<tr>
<TD height= "colspan=" 2 "align=" center "valign=" middle "><a href=" javascript:loadimage (); " ><font class=pt95> don't count me </font></a></td>
</tr>
<tr>
<TD height= "colspan=" "2" align= "center" valign= "middle" ><input type= "submit" name= "Login" value= "Submission" > </td>
</tr>
</form>
</table>
</body>
Validate.jsp--------------------------used to verify that the input verification code is correct
The code is as follows:
Copy Code code as follows:
<%@ page contenttype= "text/html; charset=gb2312 "language=" java "import=" java.sql.* "errorpage=" "%>"
<%
String rand = (string) session.getattribute ("Rand");
String input = Request.getparameter ("Rand");
if (rand.equals (input)) {
Out.print ("<script>alert" (' Validation passed!) ');</script> ");
} else{
Out.print ("<script>alert" Please enter the correct authentication code!) '); location.href= ' login.jsp ';</script> ');
}
%>
The above three JSP pages are placed in and Web-inf sibling directory, if you put in a different folder, then the relevant pages within the path of their own a little change on it.
Friendship Hint: TOMCAT5 The following version will appear abnormal
