JSP Verification Code (Verification Code) Implementation

1. Download necessary files
   1) download Jakarta-taglibs:
   Http://people.apache.org/builds/jakarta-taglibs-sandbox/nightly/
   Extract the taglibs-image.jar and place it in/WEB-INF/lib.
   Copy taglibs-image.tld to/WEB-INF/

   2) download poor man's imaging wrapper: The Image Tag uses this package.
   The http://www.mullassery.com/downloads/ can be downloaded for free after entering some necessary information
   Decompress the package and copy pmiw. jar to/WEB-INF/lib.
   

2. Configure imageservlet in Web. xml
   <Context-param>
   <Param-Name> imageservletmapping </param-Name>
   <Param-value>/Gen-image </param-value>
   </Context-param>
   <Servlet>
   <Servlet-Name> imageservlet </servlet-Name>
   <Servlet-class> org. Apache. taglibs. image. imageservlet </servlet-class>
   </Servlet>
   <Servlet-mapping>
   <Servlet-Name> imageservlet </servlet-Name>
   <URL-pattern>/Gen-image/* </url-pattern>
   </Servlet-mapping>
   
3. Add implementation code in the JSP page (some content refer to the http://technology.a.lunqun.com/read.php? Tid = 149894 & page = E & fpage = 1)

   1) Add <% @ taglib uri = "/WEB-INF/taglibs-image.tld" prefix = "IMG" %>

   2) Add at the top of the page
   <%
   Response. setheader ("Pragma", "No-Cache ");
   Response. setheader ("cache-control", "No-Cache ");
   Response. setdateheader ("expires", 0 );
   %>

   3) Add the following code where you want to add the verification code:
   <%
   Int num = (INT) Java. Lang. Math. Round (Java. Lang. Math. Random () * 8999 );
   String srand = "" + (1000 + num );
   Session. setattribute ("userinfo. authcode", srand );
   %>

   
   
   "x =" 7 "Y ="-1 "font =" Times New Roman "bold =" false "size =" 22 "color =" 0x993399 "italic = "True"/>
   "x =" 17 "Y ="-1 "font =" Times New Roman "bold =" false "size =" 22 "color =" 0x660033 "italic = "false"/>
   "x =" 27 "Y ="-1 "font =" Times New Roman "bold =" true "size =" 18 "color =" 0xcc3366 "italic =" true "/>
   "x =" 37 "Y ="-1 "font =" Times New Roman "bold =" false "size =" 22 "color =" 0x990099 "italic = "false"/>
   
   <% IF (Num <4500) {%>
   
   <% }%>
   </IMG: Image>