JSTL nedir?

JSTL nedir?

JSTL yani JavaServer Pages Standard Tag Library, JSP sayfalarında basit taglar ile java işlemleri yapmaya yarar.

Nasıl kullanılır?

JSP sayfasına bir taglib direktifi vererek kullanılabilir.

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

JSTL kütüphaneleri ve sağladıkları destekler

• Core: http://java.sun.com/jsp/jstl/core
• XML: http://java.sun.com/jsp/jstl/xml
• Internationalization: http://java.sun.com/jsp/jstl/fmt
• SQL: http://java.sun.com/jsp/jstl/sql
• Functions: http://java.sun.com/jsp/jstl/functions

Area	Subfunction	Prefix
Core	Variable support	c
	Flow control
	URL management
	Miscellaneous
XML	Core	x
	Flow control
	Transformation
I18N	Locale	fmt
	Message formatting
	Number and date formatting
Database	SQL	sql
Functions	Collection length	fn
	String manipulation

Core library

Temel işlemler yapılabilir. foreach, if, try-catch, vb.

Area	Function	Tags	Prefix
Core	Variable support	remove set	c
	Flow control	choose when otherwise forEach forTokens if
	URL management	import param redirect param url param
	Miscellaneous	catch out

Core library örnekleri

a. Variable support / değişken destek tagları

<c:set var="foo" scope="session" value="..."/>

<c:set var="foo">
     ...
 </c:set>

<c:set var="bookId" value="${param.Remove}"/>

<c:remove var="cart" scope="session"/>


<c:set var="bookId" scope="page" value="#{BooksBean.books}"/>
...
<h:inputText id="bookId" value="#{bookId}"/>
...

b. Flow control / akış kontrolü tagları

<%
     Iterator i = cart.getItems().iterator();
    while (i.hasNext()) {
        ShoppingCartItem item =
            (ShoppingCartItem)i.next();
        ...
%>
        <tr>
        <td align="right" bgcolor="#ffffff">
         ${item.quantity}
        </td>
        ...
<%
     }
 %>

...

c. Conditional / koşullu taglar

<c:if test="${!empty param.Add}">
    <c:set var="bid" value="${param.Add}"/>
    <jsp:useBean id="bid"  type="java.lang.String" />
     <sql:query var="books"
         dataSource="${applicationScope.bookDS}">
        select * from PUBLIC.books where id = ?
        <sql:param value="${bid}" />
    </sql:query>
    <c:forEach var="bookRow" begin="0" items="${books.rows}">
         <jsp:useBean id="bookRow" type="java.util.Map" />
        <jsp:useBean id="addedBook"
            class="database.Book" scope="page" />
    ...
    <% cart.add(bid, addedBook); %>
...
</c:if>

...

<c:choose>
     <c:when test="${customer.category == ’trial’}" >
         ...
     </c:when>
     <c:when test="${customer.category == ’member’}" >
         ...
     </c:when>
         <c:when test="${customer.category == ’preferred’}" >
         ...
     </c:when>
     <c:otherwise>
         ...
     </c:otherwise>
 </c:choose>

...

<c:choose>
     <c:when test="${count == 0}" >
         No records matched your selection.
     </c:when>
     <c:otherwise>
         ${count} records matched your selection.
     </c:otherwise>
 </c:choose>

...

<c:forEach var="item" items="${sessionScope.cart.items}">
    ...
    <tr>
         <td align="right" bgcolor="#ffffff">
         ${item.quantity}
    </td>
    ...
</c:forEach>

d. Iterator tagları

<c:forEach var="book" items="#{BooksBean.books}">
    ...
    <h:inputText id="quantity" value="#{book.quantity}"/>
    ...
</c:forEach>

...

<acme:transform>
    <jsp:include page="/exec/employeesList"/>
<acme:transform/>

...

<c:import url="/books.xml" var="xml" />
<x:parse doc="${xml}" var="booklist"
     scope="application" />

...

<c:url var="url" value="/catalog" >
    <c:param name="Add" value="${bookId}" />
</c:url>
<p><strong><a href="${url}">

...

<c:out value="value" [escapeXml="{true|false}"]
     [default="defaultValue"] />

...

Kaynaklar

http://docs.oracle.com/javaee/5/tutorial/doc/bnakc.html

http://docs.oracle.com/javaee/5/jstl/1.1/docs/tlddocs/c/tld-summary.html

http://docs.oracle.com/javaee/5/jstl/1.1/docs/api/