JSP with JSTL : JSP Standard Tag Library
| JSTL |
Java Server Pages Standard Tag Library
Java Server Pages Standard Tag Library (JSTL) encapsulates as simple tags the core functionality common to many Web applications. JSTL has support for common, structural tasks such as iteration and conditionals, tags for manipulating XML documents, internationalization tags, and SQL tags. It also provides a framework for integrating existing custom tags with JSTL tags.
The JSTL 1.2 Maintenace Release aligns with the Unified Expression Language (EL) that is being delivered as part of the JavaServer Pages (JSP) 2.1 specification. Thanks to the Unified EL, JSTL tags, such as the JSTL iteration tags, can now be used with JavaServer Faces components in an intuitive way.
JSTL 1.2 is part of the Java EE 5 platform.
Download the binary distribution of JSTL from Apache Standard Taglib
The JSTL Tags contains below classification
- Core Tags
- Formatting tags
- JSTL Functions
- SQL tags
- XML tags
Core Tags
The core tags are the most commonly used JSTL tags. Below is the list and URI needs to include
<%@ taglib prefix = "c" uri = "http://java.sun.com/jsp/jstl/core" %>
| Tag with above prefix and Description | |
|---|---|
| <c:out> | Like <%= … >, but for expressions. |
| <c:set > | Sets the result of an expression evaluation in a ‘scope’ |
| <c:remove > | Removes a scoped variable (from a particular scope, if specified). |
| <c:if> | Simple conditional tag which evalutes its body if the supplied condition is true. |
| <c:choose> | Simple conditional tag that establishes a context for mutually exclusive conditional operations, marked by <when> and <otherwise>. |
| <c:when> | Subtag of <choose> that includes its body if its condition evalutes to ‘true’. |
| <c:otherwise > | Subtag of <choose> that follows the <when> tags and runs only if all of the prior conditions evaluated to ‘false’. |
| <c:import> | Retrieves an absolute or relative URL and exposes its contents to either the page, a String in ‘var’, or a Reader in ‘varReader’. |
| <c:forEach > | The basic iteration tag, accepting many different collection types and supporting subsetting and other functionality . |
| <c:forTokens> | Iterates over tokens, separated by the supplied delimeters. |
| <c:redirect > | Redirects to a new URL. |
| <c:param> | Adds a parameter to a containing ‘import’ tag’s URL. |
| <c:catch> | Catches any Throwable that occurs in its body and optionally exposes it. |
| <c:url> | Creates a URL with optional query parameters |
Formatting tags
The Formatting tags are used to format and display text, the date, the time, and numbers for internationalized Websites.
<%@ taglib prefix = "fmt" uri = "http://java.sun.com/jsp/jstl/fmt" %>
| Tag with above prefix and Description | |
|---|---|
| <fmt:parseNumber> | Parses the string representation of a number, currency, or percentage. |
| <fmt:formatDate> | Formats a date and/or time using the supplied styles and pattern. |
| <fmt:formatNumber> | To render numerical value with specific precision or format. |
| <fmt:parseDate> | Parses the string representation of a date and/or time. |
| <fmt:bundle> | Loads a resource bundle to be used by its tag body. |
| <fmt:setLocale> | Stores the given locale in the locale configuration variable. |
| <fmt:setBundle> | Loads a resource bundle and stores it in the named scoped variable or the bundle configuration variable. |
| <fmt:timeZone> | Specifies the time zone for any time formatting or parsing actions nested in its body. |
| <fmt:setTimeZone> | Stores the given time zone in the time zone configuration variable. |
| <fmt:message> | Displays an internationalized message. |
| <fmt:requestEncoding> | Sets the request character encoding. |
JSTL Functions
The JSTL Functions has number of standard functions, and most of functions are common string manipulation functions.
<%@ taglib prefix = "fn" uri = "http://java.sun.com/jsp/jstl/functions" %>
| Tag with above prefix and Description | |
|---|---|
| fn:contains() | Tests if an input string contains the specified substring. |
| fn:containsIgnoreCase() | Tests if an input string contains the specified substring in a case insensitive way. |
| fn:endsWith() | Tests if an input string ends with the specified suffix. |
| fn:startsWith() | Tests if an input string starts with the specified prefix. |
| fn:escapeXml() | Escapes characters that can be interpreted as XML markup. |
| fn:indexOf() | Returns the index withing a string of the first occurrence of a specified substring. |
| fn:join() | Joins all elements of an array into a string. |
| fn:split() | Splits a string into an array of substrings. |
| fn:length() | Returns the number of items in a collection, or the number of characters in a string. |
| fn:replace() | Returns a string resulting from replacing in an input string all occurrences with a given string. |
| fn:substring() | Returns a subset of a string. |
| fn:substringAfter() | Returns a subset of a string following a specific substring. |
| fn:substringBefore() | Returns a subset of a string before a specific substring. |
| fn:toLowerCase() | Converts all of the characters of a string to lower case. |
| fn:toUpperCase() | Converts all of the characters of a string to upper case. |
| fn:trim() | Removes white spaces from both ends of a string. |
SQL tags
The SQL tags library provides tags for interacting with relational databases (RDBMSs) such as Oracle, MySQL, or Microsoft SQL Server.
<%@ taglib prefix = "sql" uri = "http://java.sun.com/jsp/jstl/sql" %>
| Tag with above prefix and Description | |
|---|---|
| <sql:setDataSource> | Creates a simple DataSource suitable only for prototyping. |
| <sql:query> | Executes the SQL query defined in its body or through the sql attribute. |
| <sql:update> | Executes the SQL update defined in its body or through the sql attribute. |
| <sql:param> | Sets a parameter in an SQL statement to the specified value. |
| <sql:dateParam> | Sets a parameter in an SQL statement to the specified java.util.Date value. |
| <sql:transaction> | Provides nested database action elements with a shared Connection, set up to execute all statements as one transaction. |
XML tags
The XML tags are a JSP-centric way of creating and manipulating the XML documents. Following is the syntax to include the JSTL XML library in your JSP.
<%@ taglib prefix = "x" uri = "http://java.sun.com/jsp/jstl/xml" %>
you will need to copy the following two XML and XPath related libraries into your
xalan.jar − Download it from link xalan.jar
XercesImpl.jar − Download it from link XercesImpl.jar
| Tag with above prefix and Description | |
|---|---|
| <x:out> | Like <%= … >, but for XPath expressions. |
| <x:parse> | Used to parse the XML data specified either via an attribute or in the tag body. |
| <x:set > | Sets a variable to the value of an XPath expression. |
| <x:if > | Evaluates a test XPath expression and if it is true, it processes its body. If the test condition is false, the body is ignored. |
| <x:forEach> | To loop over nodes in an XML document. |
| <x:choose> | Simple conditional tag that establishes a context for mutually exclusive conditional operations, marked by <when> and <otherwise> tags. |
| <x:when > | Subtag of <choose> that includes its body if its expression evalutes to ‘true’. |
| <x:otherwise > | Subtag of <choose> that follows the <when> tags and runs only if all of the prior conditions evaluates to ‘false’. |
| <x:transform > | Applies an XSL transformation on a XML document. |
| <x:param > | Used along with the transform tag to set a parameter in the XSLT stylesheet. |
| JSTL Examples |
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