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Sometimes a series of string processing is required on a JSP page, and a custom El function is required.
First look at the TLD file for the El function:
Standard.jar below:
Custom El Functions:
1. Write the El function ( all public static adornments )
The following function replaces a string with a later format
Packagecn.xm.exam.MyElFunction;/*** Custom El function, easy to handle some complex string substitution functions in JSP * *@authorQiaoliqiang * @time October 29, 2017 pm 9:09:47*/ Public classmyelfunction {/*** Replace the source string with S1-S2, for example: S1:1234,S2:ABCD to change 1 in source to a,2 for B "* *@paramSource * String that needs to be replaced *@paramS1 * before replacement: 1 2 3 4 5 *@paramS2 * After replacement: A B C D E *@return */ Public Staticstring Replace (string source, string s1, string s2) { for(inti = 0, length_1 = s1.length (); i < length_1; i++) {Source=Source.replace (S1.charat (i), S2.charat (i)); } returnsource; }}
2. Write the TLD file description (TLD file in the Web-inf directory, describe the function you just wrote, the tail can refer to Standard.jar/meta-inf/fn.tld)
TLD file plus unique URI (easy to introduce this URI in JSP)
<?XML version= "1.0" encoding= "UTF-8"?><taglibxmlns= "HTTP://JAVA.SUN.COM/XML/NS/J2EE"Xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"xsi:schemalocation= "Http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"version= "2.0"> <Description>JSTL 1.1 Functions Library</Description> <Display-name>JSTL functions</Display-name> <tlib-version>1.1</tlib-version> <Short-name>Myelfunction</Short-name> <URI>/myfunction</URI> <function> <Description>Replace 1234 in the first parameter with ABCD</Description> <name>Replace</name> <Function-class>Cn.xm.exam.MyElFunction.MyElFunction</Function-class> <function-signature>String Replace (java.lang.String, java.lang.String, java.lang.String)</function-signature> <Example>${replace ("126352", "1234", "ABCD")}</Example> </function></taglib>
Used in 3.JSP
<%@ Pagelanguage= "Java"ContentType= "text/html; charset=utf-8"pageencoding= "UTF-8"%><% @taglibURI= "/myfunction"prefix= "my"%><!DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "Http://www.w3.org/TR/html4/loose.dtd "><HTML><Head><Metahttp-equiv= "Content-type"content= "text/html; charset=utf-8"><title>Insert Title here</title></Head><Body>${my:replace ("12345", "1234", "ABCD")}</Body></HTML>
Results:
Use in conjunction with El function in 4.JSP
<%@ Pagelanguage= "Java"ContentType= "text/html; charset=utf-8"pageencoding= "UTF-8"%><% @taglibURI= "/myfunction"prefix= "my"%><!DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "Http://www.w3.org/TR/html4/loose.dtd "><HTML><Head><Metahttp-equiv= "Content-type"content= "text/html; charset=utf-8"><title>Insert Title here</title><% Request.setattribute("Test", "section");></Head><Body>${my:replace (test, "1234", "ABCD")}</Body></HTML>
Results:
ACB
Parse: The above custom function takes the test out of the field and then replaces the test
[JSP] Custom El functions and using the
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