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1. If labelIftag.java filePackage Com.rk.tag;import Java.io.ioexception;import Javax.servlet.jsp.jspexception;importJavax.servlet.jsp.tagext.jspfragment;import Javax.servlet.jsp.tagext.simpletagsupport;public class IfTag extends Simpletagsupport{private boolean test;public void Settest (Boolean test) {this.test = test;}@Overridepublic void Dotag () throws Jspexception, ioexception{//determines whether to output the label body content if (test = = True), based on the return value of the test {//j

The last article is about the core tags commonly used in Jstl, this article describes the use of JSTL custom tags. Remember when learning JS, we learned the jquery framework, at the same time learning to construct their own JS library, and then to call their own JS library, it is like according to their own needs of a cohesive function, we create a function, then call this function. In learning the Java EE Specification jstl tag section, we can also construct our own tag library according to our

the code and place the class file in the class library of the program. Then, you will need a Tag Library Descriptor (TLD) file, which is an XML file to match your operation name and the corresponding Tag manager class. MyAction com.myactions.MyActionTag (whatever) myData Related Trialware◆ DbUtils (Apache Software Foundation)◆ IBM Informix JDBC Driver (IBM)◆ MySQL Connector/J 3.0 (MySQL AB)◆ SQL4X Manager J 2.2 (MacosGuru)◆ Informix D

type set Execute operations in EL expressions Syntax: $ {operational expression}. EL expressions support the following operators: Empty OPERATOR: checks whether the variable is null or "null"Binary Expression: $ {user! = Null? User. name: ""} Obtain objects in Web Development 11 implicit objects are defined in EL Expression Language. Using these implicit objects, you can easily obtain some common objects in web development and read the data of these objects.Syntax: $ {implicit object name}: Ge

Tag library~ Write a class that contains a method to be called by El, this method must be a static method~ Write a TLD file in which to describe the static method to be called ~ taglib directives in JSP pages to introduce TLD files into the current JSP page so that the described method can be called in the JSP page 3.JSTL: !! !! !! The !! 4. Custom Label Technology: Tags: jsp can be used to gene

Custom labels can greatly facilitate the authoring of our page controls, and can achieve a lot of unified management.0, first need to introduce the support of custom label jar package, there are two ways,One is to introduce dependencies directly into Maven: The other is directly with your Tomcat JSP-API.You can take one of two ways.1. Custom method labels via TLD filesThis usage of TLD allows us to u

; picture size not exceeding $maxsize MB ";}$folder = ' files/';if (!is_dir ($folder)) {mkdir ($folder);}$folder. = $_post[' folder '? $_post[' folder '. ‘/‘ : ‘‘;if (!is_dir ($folder)) {mkdir ($folder);} if (Preg_match ('/image/i ', $_files[' xfile ' [' type '])) {$filename = $_post[' value ']? $_post[' value ']: $folder. SHA1 (@microtime (). ‘-‘ . $_files[' XFile ' [' Name ']). '. jpg ';}else{$tld = Split (', ', $_files[' xfile ' [' name ']);$

: ""}-----Ternary operator3, EL 11 built-in objectsPagescope Requestscope sessionscope applicationscope Four data range, used to take a valuePageContext Current JSP context-----${pagecontext.request.contextpath}${param.name} equivalent to Request.getparameter ("name")${paramvalues.hobby} equivalent to Request.getparametervalues ("hobby")${header.referer} equivalent to Request.getheader ("Referer")${headervalues["Accept-encoding"} is equivalent to Request.getheaders ("accept-encoding")${initparam

This example describes the use of JSP custom tags. Share to everyone for your reference. Specifically as follows: There is a mechanism in JSP that allows you to insert markup similar to HTML in a JSP page. This article describes the basic concepts and composition of JSP custom tags, and how to develop and apply JSP custom tags. What is a tag Using the HTML language we can edit our web pages like this: Here we call In the example above, The process of the JSP ser

JSP page. Here, the Java code is moved out of the scriptlet and placed in a custom label: The date and time at the server are: In this example, Create a user-defined label processor Creating a user-defined label processor requires more than a certain amount of work for a scriptlet because of this Java class, and you have to write a descriptor file for him in the TLD format (described in the next section). The following class D

* 1048576)) {$r->error = "picture size" > picture size not exceeding $maxsize MB ";}$folder = ' files/';if (!is_dir ($folder)) {mkdir ($folder);}$folder. = $_post[' folder ']? $_post[' folder ']. '/' : '';if (!is_dir ($folder)) {mkdir ($folder);}if (Preg_match ('/image/i ', $_files[' xfile '] [' type '])) {$filename = $_post[' value ']? $_post[' value ': $folder. SHA1 (@microtime (). '-' . $_files[' XFile ' [' name ']]. '. jpg ';}else{$tld = Split ('

classes are invoked in El expressions, and the static method of this Java class needs to be described in the TLD file before it can be invoked by an El expression. El custom functions are used to extend the functionality of El expressions, allowing El expressions to perform the functions that ordinary Java program code can accomplish. 1.5. EL function Development Steps In general, the development and application of El Custom functions consists of

Tag Library taglib tags are defined and distributed in a structure called a tag library, which is a collection of meta information and classes: 1. Label Processor: Java class that implements custom label functions. 2. Tag additional information (TEI): Provides a side series to the JSP container to confirm the label attributes and the class that created the variable. 3. Tag Library Descriptor (TLD): An XML document that describes the properties of

Java class can only be called in an El expression, and the static method of the Java class needs to be described in the TLD file before it can be called by an El expression.The El Custom function is used to extend the functionality of the El expression, allowing the El expression to do what ordinary Java program code can do.1.5. EL function Development StepsIn general, the development and application of El Custom functions consists of the following t

, and the static method of the Java class needs to be described in the TLD file before it can be called by an El expression.The El Custom function is used to extend the functionality of the El expression, allowing the El expression to do what ordinary Java program code can do.1.5. EL function Development StepsIn general, the development and application of El Custom functions consists of the following three steps:1. Write a static method of a Java clas