Category Archives: JSTL

Defining a Simple Custom Tag TLD

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CustomTags.java
This is the File which defines the Property of the Tag

package com.mugil.custTags;

import java.io.IOException;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;

public class CustomTags extends TagSupport  
{
  private static final long serialVersionUID = 1L;
	
  public int doStartTag() throws JspException 
  {		
     StringBuffer SamBuffer = new StringBuffer();
     SamBuffer.append("Sample Message");
		
     try
     {
	pageContext.getOut().write(SamBuffer.toString());
     }
     catch (IOException e)
     {
	e.printStackTrace();
     }
		
  	return EVAL_PAGE;
   }
	
   public int doEndTag() throws JspException 
   {
      return EVAL_PAGE;
   }
}

DisplayName.tld
This xml file creates the Relation between the tag and the property of the tag as defined in the java file.

<?xml version="1.0" encoding="UTF-8"?>
<taglib>
  <tlib-version>1.0</tlib-version>
  <jsp-version>2.0</jsp-version>
  <shortname>Example TLD</shortname>
  <tag>
    <name>Hello</name>
    <tagclass>com.mugil.custTags.CustomTags</tagclass>
    <bodycontent>empty</bodycontent>
  </tag>
</taglib>

Sample.jsp
JSP File in which the custom tag is Used.

<%@taglib prefix="DisplayName" uri="/WEB-INF/tld/DisplayName.tld"%>
.
.
.
.
<body>
 <h1>
    <DisplayName:Hello/>
 </h1>
</body>
.
.
.

web.xml

 <?xml version="1.0" encoding="UTF-8"?>
  <web-app version="3.0">
   <servlet>
     <servlet-name>TestServlet</servlet-name>
     <servlet-class>com.mugil.custTags.TestServlet</servlet-class>
   </servlet>
   <servlet-mapping>
     <servlet-name>TestServlet</servlet-name>
     <url-pattern>/TestServlet/</url-pattern>
   </servlet-mapping>
  </web-app>

Output

OP

JSTL Using Basic Tags

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c:forEach

 <body>
   <c:forEach var="i" begin="1" end="100">
     <c:out value="${i}"/><br/>
   </c:forEach>
 </body>

Accessing Value in Bean
SampleMenu.java(bean)

  public class SampleMenu
  {
    String name;
  
    public String getName()
    {
      return name;
    }
	
    public void setName(String name)
    {
      this.name = name;
    }
  }

MenuList.java

   List<SampleMenu> arrMenuList = new ArrayList<SampleMenu>();		
   SampleMenu objSampleMenu     = new SampleMenu();

   objSampleMenu.setName("Link1");
   arrMenuList.add(objSampleMenu); 

   objSampleMenu.setName("Link2");
   arrMenuList.add(objSampleMenu);

   objSampleMenu.setName("Link3");
   arrMenuList.add(objSampleMenu);

   request.setAttribute("arrMenuList", arrMenuList);
   RequestDispatcher dispatcher = request.getServletContext().getRequestDispatcher("/Sample.jsp");
   dispatcher.forward(request, response);

Sample.java

 
   <body>
     <c:forEach	var="i" items="${arrMenuList}">
	     <c:out value="${i.name}"/>
     </c:forEach>
   </body>

Output
Link1 Link2 Link3

If Else 

 
<c:if test="${user.userGender eq 1}">Male</c:if>
<c:if test="${user.userGender eq 0}">Female</c:if>

(or)

 
  <c:choose>
    <c:when test="${user.userGender eq 1}">Male</c:when>
    <c:otherwise>Female</c:otherwise>
  </c:choose>

Alternative to If Else Statement

 
 <c:out value="${user.userGender eq 1 ? 'Male': 'Female'}"/>

If Else If

<c:choose>
    <c:when test="${empty example1}"> 
        <!-- do stuff -->
    </c:when> 
    <c:otherwise> 
        <c:choose>
            <c:when test="${empty example2}"> 
                <!-- do different stuff -->
            </c:when> 
            <c:otherwise> 
                <!-- do default stuff -->
            </c:otherwise>
        </c:choose>
    </c:otherwise> 
</c:choose>

If Else If

<c:choose>
    <c:when test="${empty example1}">
    </c:when>
    <c:when test="${empty example2}">
    </c:when>
    <c:otherwise>
    </c:otherwise>              
</c:choose>