Java JSP Standard Tag Library (JSTL) Tutorial

1- Introduction

This document is based on:
  • Eclipse 4.5 Mars
  • Tomcat 8.0

2- What is JSTL?

JSP Standard Tag Library (JSTL) is the standard tag library that provides tags to control the JSP page behavior, iteration and control statements, internationalization tags, and SQL tags.

JSTL is part of the Java EE API and included in most servlet containers. But to use JSTL in your JSP pages, you need to download the JSTL jars for your servlet container. Most of the times, you can find them in the example projects and you can use them. You need to include these libraries in the project WEB-INF/lib directory. If your project is a Maven project you need to declare these libraries on pom.xml

3- JSTL Overview

Based on the JSTL functions, they are categorized into five types.
Functions Description / Declaration
Core Tags Core tags provide support for iteration, conditional logic, catch exception, url, forward or redirect response etc. To use JSTL core tags, you should include it in the JSP page like below.
  • <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
Formatting and Localization Tags These tags are provided for formatting of Numbers, Dates and i18n support through locales and resource bundles. You can include these tags in JSP with below syntax:
  • <%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>
SQL Tags: JSTL SQL Tags provide support for interaction with relational databases such as Oracle, MySql etc. Using SQL tags you can run database queries, you include it in JSP with below syntax:
  • <%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %>
XML Tags XML tags are used to work with XML documents such as parsing XML, transforming XML data and XPath expressions evaluation. Syntax to include XML tags in JSP page is:
  • <%@ taglib uri="http://java.sun.com/jsp/jstl/xml" prefix="x" %>
JSTL Functions Tags JSTL tags provide a number of functions that you can use to perform common operation, most of them are for String manipulation such as String Concatenation, Split String etc. Syntax to include JSTL functions in JSP page is:
  • <%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %>

4- Download JSTL libraries

First, you need to download standard  JSTL. If you downloaded  Tomcat server, library files are in the folder:
  • <Tomcat>/webapps/examples/WEB-INF/lib
    • taglibs-standard-impl-**.jar
    • taglibs-standard-spec-**.jar
Normally, standard JSTL libraries named  taglibs-standard-spec-**.jar and  taglibs-standard-impl-**.jar. Sometimes, these librabries called under different name such as   javax.servlet.jsp.jstl-*.jar, javax.servlet.jsp.jslt-api-*.jar.
JSTL library
(Provided by Apache)
JSTL library
(Provided by Glassfish)
taglibs-standard-spec-*.jar javax.servlet.jsp.jslt-api-*.jar
taglibs-standard-impl-*.jar javax.servlet.jsp.jstl-*.jar
If you use Maven:
  • Provided by Apache:
<!-- taglibs-standard-spec-*.jar -->
<!-- http://mvnrepository.com/artifact/org.apache.taglibs/taglibs-standard-spec -->
<dependency>
    <groupId>org.apache.taglibs</groupId>
    <artifactId>taglibs-standard-spec</artifactId>
    <version>1.2.5</version>
</dependency>

<!-- taglibs-standard-impl-*.jar -->
<!-- http://mvnrepository.com/artifact/org.apache.taglibs/taglibs-standard-impl -->
<dependency>
    <groupId>org.apache.taglibs</groupId>
    <artifactId>taglibs-standard-impl</artifactId>
    <version>1.2.5</version>
</dependency>
  • Or Provided by Glassfish:
<!-- http://mvnrepository.com/artifact/org.glassfish.web/javax.servlet.jsp.jstl -->
<dependency>
   <groupId>org.glassfish.web</groupId>
   <artifactId>javax.servlet.jsp.jstl</artifactId>
   <version>1.2.4</version>
</dependency>

<!-- http://mvnrepository.com/artifact/javax.servlet.jsp.jstl/javax.servlet.jsp.jstl-api -->
<dependency>
   <groupId>javax.servlet.jsp.jstl</groupId>
   <artifactId>javax.servlet.jsp.jstl-api</artifactId>
   <version>1.2.1</version>
</dependency>
  • Provided by the Sun (Slightly older, rarely used now).
<!-- standard.jar -->
<!-- http://mvnrepository.com/artifact/taglibs/standard -->
<dependency>
   <groupId>taglibs</groupId>
   <artifactId>standard</artifactId>
   <version>1.1.2</version>
</dependency>

<!-- jstl-*.jar -->
<!-- http://mvnrepository.com/artifact/javax.servlet/jstl -->
<dependency>
   <groupId>javax.servlet</groupId>
   <artifactId>jstl</artifactId>
   <version>1.2</version>
</dependency>

Download:

You can download these libraries provided by   Apache from  Maven Repository:
 
The results you download are:

5- Create WebApp project

To learn JSTL you need to create a project Web App to run the examples:
  • File/New/Other..
Enter project name:
  • JSTLTutorial
Project is created.

6- JSTL library declaration

Copy the JSTL libraries into the WEB-INF/lib

7- Configuring Webapp

First of all, you need to download and declare  Tomcat Server with Eclipse. You can find the instruction at
Configure to run webapp:
Right-click the project and select Properties.
Right-click the project and select:
  • Run As/Run on Server
Do not worry if you get a message like this, simply because your website does not have any page.

8- The classes participated in the examples

You need some classes which  participate in the examples in this document.
Dept.java
package org.o7planning.jslttutorial.beans;

import java.util.HashSet;
import java.util.Set;

public class Dept {

  private int deptNo;
  private String deptName;
  private String location;

  private Set<Emp> employees;

  public Dept() {

  }

  public Dept(int deptNo, String deptName, String location) {
      this.deptNo = deptNo;
      this.deptName = deptName;
      this.location = location;
  }

  public int getDeptNo() {
      return deptNo;
  }

  public void setDeptNo(int deptNo) {
      this.deptNo = deptNo;
  }

  public String getDeptName() {
      return deptName;
  }

  public void setDeptName(String deptName) {
      this.deptName = deptName;
  }

  public String getLocation() {
      return location;
  }

  public void setLocation(String location) {
      this.location = location;
  }

  public Set<Emp> getEmployees() {
      return employees;
  }

  public void setEmployees(Set<Emp> employees) {
      this.employees = employees;
  }
 
  public void addEmployee(Emp employee)  {
      if(this.employees== null)  {
          this.employees= new HashSet<Emp>();
      }
      this.employees.add(employee);
  }
}
Emp.java
package org.o7planning.jslttutorial.beans;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Emp {

   private int empNo;
   private String empName;
   private String job;

   private Date hireDate;
   private float salary;

   private static final DateFormat df = new SimpleDateFormat("MM/dd/yyyy");

   public Emp() {

   }


   // @hireDateStr - must have the format 'MM/dd/yyyy'.
   public Emp(int empNo, String empName, String job,
           String hireDateStr, float salary)  {
       this.empNo = empNo;
       this.empName = empName;
       this.job = job;
       this.salary = salary;
       try {
           this.hireDate = df.parse(hireDateStr);
       } catch (ParseException e) {
           throw new RuntimeException(e);
       }
   }

   public int getEmpNo() {
       return empNo;
   }

   public void setEmpNo(int empNo) {
       this.empNo = empNo;
   }

   public String getEmpName() {
       return empName;
   }

   public void setEmpName(String empName) {
       this.empName = empName;
   }

   public String getJob() {
       return job;
   }

   public void setJob(String job) {
       this.job = job;
   }

   public Date getHireDate() {
       return hireDate;
   }

   public void setHireDate(Date hireDate) {
       this.hireDate = hireDate;
   }

   public float getSalary() {
       return salary;
   }

   public void setSalary(float salary) {
       this.salary = salary;
   }

}
DBUtils.java
package org.o7planning.jslttutorial.utils;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

import org.o7planning.jslttutorial.beans.Dept;
import org.o7planning.jslttutorial.beans.Emp;

public class DBUtils {

    private static final List<Dept> DEPARTMENTS = new ArrayList<Dept>();

    static {
        initData();
    }

    // Simulation data in the database.
    private static void initData() {

        Dept accountingDept = new Dept(10, "ACCOUNTING", "NEW YORK");
        accountingDept.addEmployee(new Emp(7782, "CLARK", "MANAGER", "6/9/1981", 2450.00f));
        accountingDept.addEmployee(new Emp(7839, "KING", "PRESIDENT", "11/17/1981", 5000.00f));
        accountingDept.addEmployee(new Emp(7934, "MILLER", "CLERK", "6/9/1981", 1300.00f));

        //
        Dept reseachDept = new Dept(20, "RESEARCH", "DALLAS");
        reseachDept.addEmployee(new Emp(7369, "SMITH", "CLERK", "12/17/1980", 800.00f));
        reseachDept.addEmployee(new Emp(7788, "SCOTT", "ANALYST", "4/19/1987", 3000.00f));
        reseachDept.addEmployee(new Emp(7876, "ADAMS", "CLERK", "5/23/1987", 1100.00f));
        reseachDept.addEmployee(new Emp(7876, "FORD", "ANALYST", "12/3/1981", 3000.00f));
        reseachDept.addEmployee(new Emp(7566, "JONES", "MANAGER", "4/2/1981", 2975.00f));
        //
        //
        Dept salesDept = new Dept(30, "SALES", "CHICAGO");
        salesDept.addEmployee(new Emp(7654, "MARTIN", "SALESMAN", "9/28/1981", 1250.00f));
        salesDept.addEmployee(new Emp(7499, "ALLEN", "SALESMAN", "2/20/1981", 1600.00f));
        salesDept.addEmployee(new Emp(7521, "WARD", "SALESMAN", "2/22/1981", 1250.00f));
        salesDept.addEmployee(new Emp(7844, "TURNER", "SALESMAN", "9/8/1981", 1500.00f));
        salesDept.addEmployee(new Emp(7900, "JAMES", "CLERK", "12/3/1981", 950.00f));
        //
        Dept openrationsDept = new Dept(40, "OPERATIONS", "BOSTON");
        //

        DEPARTMENTS.add(accountingDept);
        DEPARTMENTS.add(reseachDept);
        DEPARTMENTS.add(salesDept);
        DEPARTMENTS.add(openrationsDept);
    }

    // Queries departments.
    public static List<Dept> queryDepartments() {
        return DEPARTMENTS;
    }

    // Query the employees in a department.
    public static Set<Emp> queryEmployees(int deptNo) {
        for (Dept dept : DEPARTMENTS) {
            if (deptNo == dept.getDeptNo()) {
                return dept.getEmployees();
            }
        }
        return null;
    }
}

9- JSTL Core Tags

Tag Description
<c:out> To write something in JSP page, you can use EL also with this tag
<c:import> Same as <jsp:include> or include directive
<c:redirect> redirect request to another resource
<c:set> To set the variable value in given scope.
<c:remove> To remove the variable from given scope
<c:catch> To catch the exception and wrap it into an object.
<c:if> Simple conditional logic, used with EL and you can use it to process the exception from <c:catch>
<c:choose> Simple conditional tag that establishes a context for mutually exclusive conditional operations, marked by <c:when> and <c:otherwise>
<c:when> Subtag of <c:choose> that includes its body if its condition evalutes to ‘true’.
<c:otherwise> Subtag of <c:choose> that includes its body if its condition evalutes to ‘false’.
<c:forEach> for iteration over a collection
<c:forTokens> for iteration over tokens separated by a delimiter.
<c:param> used with <c:import> to pass parameters
<c:url> to create a URL with optional query string parameters

9.1- EL operators

A useful feature of the EL is the ability to perform comparisons, either between numbers or objects. This feature is used primarily for the values of custom tag attributes, but can equally be used to write out the result of a comparison (true or false) to the JSP page. The EL provides the following comparison operators:
Equals == eq
Not equals != ne
Less than < lt
Greater than > gt
Less than or equals <= le
Greater than or equals >= ge
The second version of each operator exists to avoid having to use entity references in JSP XML syntax; however, the behavior of the operators is the same. See the example:
Concept EL Condition Result
Numeric less than ${1 < 2} true
Numeric greater than ${1 > 2} false
Numeric less than ${1 lt 2} true
Numeric greater than ${1 gt 2} false
Numeric Greater than or equal ${1 >= 1} true
Numeric Less than or equal ${1 <= 1} true
Numeric less than or equal ${1 le 1} true
Numeric greater than or equal ${1 ge 1} true
Numeric equal to ${1 == 1} true
Numeric equal to ${1 eq 1} true
Numeric not equal to ${1 != 2} true
Numeric not equal to ${1 ne 2} true
Alphabetic less than ${'abe' < 'ade'} true
Alphabetic greater than ${'abe' > 'ade'} false
Alphabetic equal to ${'abe' eq 'abe'} true
Alphabetic not equal to ${'abe' ne 'ade'} true
You can also use && and || operators.
Operator Description
&& And
|| Or
Example:
${(guess >= 10)  && (guess <= 20)} ${ guess >= 10  &&  guess <= 20  }
${(guess < 10)  || (guess > 20)} ${ guess < 10  ||  guess > 20 }

9.2- c:forEach

See the first example uses  <c:forEach> tag of  JSTL Core. Users access to   /jstl Core Example01 servlet, the data will be queried on Servlet, then forwarding the request to JSP page to display. JSP page using JSTL to display data.
If you do not want users to access directly to the JSP page, you can place them in the WEB-INF directory or subdirectories of this directory.
In Servlet, you can store data in an attribute of the request, this data only exists while the request taking place.
// Query data from database.
List<Dept> list = DBUtils.queryDepartments();


// set to request attribute.
request.setAttribute("departments", list);
In JSP, you can use the data that has been already stored on the attributes of the request.
<c:forEach items="${requestScope.departments}" var="dept">

  ${dept.deptName}

</c:forEach>


<!-- Or (no need requestScope)  -->

<c:forEach items="${departments}" var="dept">

  ${dept.deptName}

</c:forEach>
View full example:
JstlCoreEx01Servlet.java
package org.o7planning.jslttutorial.servlets;

import java.io.IOException;
import java.util.List;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.o7planning.jslttutorial.beans.Dept;
import org.o7planning.jslttutorial.utils.DBUtils;

@WebServlet("/jstlCoreExample01")
public class JstlCoreEx01Servlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public JstlCoreEx01Servlet() {
        super();
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        // Query data from database.
        List<Dept> list = DBUtils.queryDepartments();
        
        // Set to 'departments' attribute of request
        request.setAttribute("departments", list);

        // Create RequestDispatcher to forward the request to jstl_core_example01.jsp
        RequestDispatcher dispatcher = getServletContext()
                .getRequestDispatcher("/WEB-INF/jsps/jstl_core_example01.jsp");
        
        // Forward the request to JSP page.
        dispatcher.forward(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

}
/WEB-INF/jsps/jstl_core_example01.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8"%>

 
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
 
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>JSTL Core Tags Example 01</title>
</head>
<body>

<h2>Departments and Employees</h2>

 
<c:forEach items="${departments}" var="dept">
 <h3>${dept.deptName}</h3>
 <ul>
 
   <c:forEach items="${dept.employees}" var="emp">
       <li>
          ${emp.empName} - (${emp.job})
       </li>    
   </c:forEach>
 </ul>

</c:forEach>


</body>
</html>
Running the example:

9.3- c:if

<c:if> is used to test a certain condition is true or false. Such examples below to check if a collection has elements or not (Check if  existing department have  employee or not). This example is the same example above but  only show the departments which have employees.
JstlCoreEx02Servlet.java
package org.o7planning.jslttutorial.servlets;

import java.io.IOException;
import java.util.List;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.o7planning.jslttutorial.beans.Dept;
import org.o7planning.jslttutorial.utils.DBUtils;

@WebServlet("/jstlCoreExample02")
public class JstlCoreEx02Servlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public JstlCoreEx02Servlet() {
        super();
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        // Query data from database.
        List<Dept> list = DBUtils.queryDepartments();
        
        // Set to 'departments' attribute of request
        request.setAttribute("departments", list);

        // Create RequestDispatcher to forward the request to jstl_core_example02.jsp
        RequestDispatcher dispatcher = getServletContext()
                .getRequestDispatcher("/WEB-INF/jsps/jstl_core_example02.jsp");
        
        // Forward the request to JSP page.
        dispatcher.forward(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

}
/WEB-INF/jsps/jstl_core_example02.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8"%>

 
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
 
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>JSTL Core Tags Example 01</title>
</head>
<body>

<h2>Departments and Employees</h2>

 
<c:forEach items="${departments}" var="dept">

<!-- Check if collection is not null or not empty -->
<c:if test="${not empty dept.employees}">
     <h3>${dept.deptName}</h3>
     <ul>
      
       <c:forEach items="${dept.employees}" var="emp">
           <li>
              ${emp.empName} - (${emp.job})
           </li>    
       </c:forEach>
     </ul>
 </c:if>

</c:forEach>


</body>
</html>
Running the example:

9.4- c:choose - c:when - c:otherwise

Syntax:
<c:choose>
    <c:when test="${condition1}">
       <%-- do something if condition1 is true  --%>
    </c:when>
    <c:when test="${condition2}">
        <%-- do something if condition2 is true  --%>
    </c:when>
    <c:otherwise>
        <%-- Statements which gets executed when all <c:when> tests are false.  --%>
    </c:otherwise>
</c:choose>
Example:
c_choose.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>c:choose,c:when,c:otherwise example</title>
</head>
<body>
 
<h2>c:choose,c:when,c:otherwise example</h2>


<c:choose>
    <%-- When color parameter == 'red' --%>
    <c:when test="${param.color=='red'}">
        <p style="color:red;">RED COLOR</p>
    </c:when>  
    
    <%-- When color parameter == 'blue' --%>
    <c:when test="${param.color=='blue'}">
        <p style="color:blue;">BLUE COLOR</p>
    </c:when>  
     
    <%-- Otherwise --%> 
    <c:otherwise>
        <b>Other color</b>
    </c:otherwise>
</c:choose>

</body>
</html>
Running the example:

9.5- c:out

The <c:out> tag displays the result of an expression, similar to the way <%= %> works with a difference that <c:out> tag lets you use the simpler "." notation to access properties. For example, to access dept.deptName just use tag is <c:out value="${dept.deptName}"/>.

The <c:out> tag can automatically escape XML tags so they aren't evaluated as actual tags.
Example:
c_out.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
   
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>c:out example</title>
</head>
<body>

<h2>c:out example</h2>

<c:out value="${'This is true: 10 > 1 '}" />

<br/>
Tag: <c:out value="${'<atag> , &'}"/>

</body>
</html>
Running the example:

9.6- c:set

c_set.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
   
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>c:set example</title>
</head>
<body>

<h2>c:set example</h2>

<c:set scope="request" var="greeting" value="Hello every body" />


Greeting: <c:out value="${greeting}"/>

</body>
</html>
Running the example:

9.7- c:remove

c_remove.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
   
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>c:remove example</title>
</head>
<body>

<h2>c:remove example</h2>

<c:set scope="request" var="greeting" value="Hello every body" />


Greeting: <c:out value="${greeting}"/>
<br/><br/>

<c:remove scope="request" var="greeting" />
After remove:
<br/>
Greeting: <c:out value="${greeting}"/>

</body>
</html>
Running the example:

9.8- c:catch

c_catch.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
 
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>c:catch example</title>
</head>
<body>

<h2>c:catch example</h2>

<c:catch var ="ex">
  <%
   int a = 100/0;    
  %>
</c:catch>

<c:if test = "${ex != null}">
 Exception : ${ex}
 <br />
 Message: ${ex.message}
</c:if>

</body>
</html>
Running the example:

9.9- c:forTokens

c_forTokens.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
   
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>c:forTokens example</title>
</head>
<body>

<h2>c:forTokens example</h2>


<c:forTokens items="Tom,Jerry,Donald" delims="," var="name">
  <c:out value="${name}"/><p>
</c:forTokens>

</body>
</html>
Running the example:

9.10- c:url - c:param

c_url.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
   
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>c:url,c:param example</title>
</head>
<body>

<h2>c:url,c:param example</h2>


<c:url value="http://example.com/showPage.jsp" var="myURL">
  <c:param name="color" value="red"/>
  <c:param name="background" value="blue"/>
</c:url>

<c:out value="${myURL}"/>

</body>
</html>
Running the example:

10- JSTL Formatting and Localization Tags

The JSTL formatting tags are used to format and display text, the date, the time, and numbers for internationalized Web sites.
Tag Description
<fmt:formatNumber> To render numerical value with specific precision or format.
<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: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> To display an internationalized message.
<fmt:requestEncoding> Sets the request character encoding

10.1- fmt:formatNumber

The <fmt:formatNumber> tag is used to format numbers, percentages, and currencies.
Syntax:
<fmt:formatNumber
  value="<number>"
  type="<string>"
  pattern="<string>"
  currencyCode="<string>"
  currencySymbol="<string>"
  groupingUsed="<string>"
  maxIntegerDigits="<integer>"
  minIntegerDigits="<integer>"
  maxFractionDigits="<integer>"
  minFractionDigits="<integer>"
  var="<string>"
  scope="<string>"/>

Attribute:

Name

Required

Type

Default

Description

value

Yes

Number

 

Numeric value to be formatted.

type

 

String

number

Determines whether the value is formatted as a number, currency or percentage.

pattern

 

String

 

Formatting pattern.

currencyCode

 

String

From the default locale

The currency code to be used if the type attribute is currency.

currencySymbol

 

String

From the default locale

The currency symbol to be used if the type attribute is currency.

groupingUsed

 

String

true

Whether any grouping separated to be used when formatting the output.

maxIntegerDigits

 

Integer

 

Maximum number of digits in the integer portion.

minIntegerDigits

 

Integer

 

Minimum number of digits in the integer portion.

maxFractionDigits

 

Integer

 

Maximum number of digits in the fraction portion.

minFractionDigits

 

Integer

 

Minimum number of digits in the fraction portion.

var

 

String

Print to page

Name of the variable which stores the formatted result.

scope

 

String

 

Scope to store the var.

fmt_formatNumber.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>  
<!DOCTYPE html>
<html>
  <head>
     <meta charset="UTF-8">
     <title>fmt:formatNumber example</title>
  </head>
  <body>
     <h2>fmt:formatNumber example</h2>
     <c:set var="accountBalance" value="12345.6789" />
     <h3>accountBalance=<c:out value="${accountBalance}"/></h3>
     
     The Account Balance can be displayed using various ways:
     
     <p>
        formatNumber (type='currency'):
        <strong>
           <fmt:formatNumber value="${accountBalance}" type="currency"/>
        </strong>
     </p>
     <p>
        formatNumber (type='number', maxIntegerDigits= '3'):
        <strong>
           <fmt:formatNumber type="number" maxIntegerDigits="3" value="${accountBalance}" />
        </strong>
     </p>
     <p>
        formatNumber (type='number', maxFractionDigits= '3'):
        <strong>
           <fmt:formatNumber type="number" maxFractionDigits="3" value="${accountBalance}" />
        </strong>
     </p>
     <p>
        formatNumber (type='number', groupingUsed= 'false'):
        <strong>
           <fmt:formatNumber type="number" groupingUsed="false" value="${accountBalance}" />
        </strong>
     </p>
     <p>
        formatNumber (type='percent', maxIntegerDigits= '3'):
        <strong>
           <fmt:formatNumber type="percent" maxIntegerDigits="3" value="${accountBalance}" />
        </strong>
     </p>
     <p>
        formatNumber (type='percent', maxIntegerDigits= '10'):
        <strong>
           <fmt:formatNumber type="percent" minFractionDigits="10" value="${accountBalance}" />
        </strong>
     </p>
     <p>
        formatNumber (type='number', pattern= '###.###E0'):
        <strong>
           <fmt:formatNumber type="number" pattern="###.###E0" value="${accountBalance}" />
        </strong>
     </p>
     <p>        
        Account Balance in USA (fmt:setLocale value='en_US'):
        <br/>
        formatNumber (type='currency'):          
        <fmt:setLocale value="en_US"/>
        <strong>
           <fmt:formatNumber value="${accountBalance}" type="currency"/>
        </strong>
     <p>
        Account Balance in Canada (fmt:setLocale value='fr_CA'):
        <br/>
        formatNumber (type='currency'):
        <fmt:setLocale value="fr_CA"/>
        <strong>
           <fmt:formatNumber value="${accountBalance}" type="currency"/>
        </strong>
  </body>
 
</html>
Running the example:

10.2- fmt:parseNumber

The <fmt:parseNumber> is used to parse a series of numbers, currency or percent, and returns a number
Syntax:
<fmt:parseNumber
   value="<string>"
   type="<string>"
   pattern="<string>"
   parseLocale="<string>"
   integerOnly="<string>"
   var="<string>"
   scope="<string>"/>

Attributes:

Name

Required

Type

Default

Description

value

Yes

String

 

String to be parsed.

type

 

String

number

Determines whether the String provided in the value attribute to be parsed as a NUMBER, CURRENRY or PERCENTAGE. Default is NUMBER.

pattern

 

String

 

Pattern on how the given string in the value attribute is parsed.

parseLocale

 

String

Default locale

Locale to use when parsing the value   using the given pattern.

integerOnly

 

String

false

Specifies whether only the integer part of the value is parsed.

var

 

String

Print to page

Name of the variable which stores the result of the parsed value. The result is of type java.lang.Number.

scope

 

String

page

Scope for the var to store.

By default, <fmt:formatNumber> sends its output to the current JspWriter, but if you specify the var attribute, <fmt:formatNumber> stores its output in a scoped variable whose name is specified with the var attribute. The <fmt:formatNumber> action stores scoped variables in page scope by default, but you can specify a different scope with the scope attribute.
fmt_parseNumber.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>  
<!DOCTYPE html>
<html>
  <head>
     <meta charset="UTF-8">
     <title>fmt:parseNumber example</title>
  </head>
  <body>
     <h2>fmt:parseNumber example</h2>
     
   <!-- a String in currency format -->
   <c:set var="accountBalance" value="$12345.6789" />
   
   <h4>Input <c:out value="${accountBalance}"/></h4>    
   
   <fmt:parseNumber var="parsedNumber" type="currency"
                  parseLocale="en_US"
                  value="${accountBalance}" />
   
   <p>Account Balance: <c:out value="${parsedNumber}" /></p>
   
   <!-- integerOnly="true" : Specifies whether only
              the integer part of the value is parsed. -->
   
   <fmt:parseNumber var="parsedNumber" type="currency"
                   integerOnly="true" parseLocale="en_US"
                   value="${accountBalance}" />
                   
   <p>Account Balance (without cents): <c:out value="${parsedNumber}" /></p>
  </body>
 
</html>
Running the example:

10.3- fmt:formatDate

The <fmt:formatDate> tag to format the date or time information using provided styles and pattern.

Attributes:

Name

Required

Type

Default

Description

value

True

Date

 

Date or time to be formatted.

type

False

String

date

Determines whether date or time or both to be formatted in the given date.
(date, time, both)

dateStyle

False

String

default

Formatting style for date. The date format can be specified with similar semantics in class java.text.DateFormat.

timeStyle

False

String

default

Formatting style for time. The time format can be specified with similar semantics in class java.text.DateFormat.

pattern

False

String

 

Pattern to be used for date and time when formatting.

timeZone

False

String

Default time zone

Time zone to represent for the formatted time.

var

False

String

Print to Page

Name of the variable to store the resulted formatted date or time.

scope

False

String

page

Scope to store the var.

The format characters:
Code Purpose Sample

G

The era designator

AD

y

The year

2002

M

The month

April & 04

d

The day of the month

20

h

The hour(12-hour time)

12

H

The hour(24-hour time)

0

m

The minute

45

s

The second

52

S

The millisecond

970

E

The day of the week

Tuesday

D

The day of the year

180

F

The day of the week in the month

2 (2nd Wed in month)

w

The week in the year

27

W

The week in the month

2

a

The a.m./p.m. indicator

PM

k

The hour(12-hour time)

24

K

The hour(24-hour time)

0

z

The time zone

Central Standard Time

'

 

The escape for text

''

 

The single quote

fmt_formatDate.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
   pageEncoding="UTF-8"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>  
<!DOCTYPE html>
<html>
  <head>
     <meta charset="UTF-8">
     <title>fmt:formatDate example</title>
  </head>
  <body>
     <h2>fmt:formatDate example</h2>
     <c:set var="now" value="<%=new java.util.Date()%>" />
     <p>
        Time (fmt:formatDate type="time"):
        <strong>
           <fmt:formatDate type="time" value="${now}" />
        </strong>
     </p>
     <p>
        Date (fmt:formatDate type="date"):
        <strong>
           <fmt:formatDate type="date" value="${now}" />
        </strong>
     </p>
     <p>
        Date, Time (fmt:formatDate type="both"):
        <strong>
           <fmt:formatDate type="both" value="${now}" />
        </strong>
     </p>
     <p>
        Date, Time Short (fmt:formatDate type="both" dateStyle="short"):
        <strong>
           <fmt:formatDate type="both" dateStyle="short" timeStyle="short" value="${now}" />
        </strong>
     </p>
     <p>
        Date, Time Medium (fmt:formatDate type="both" dateStyle="medium" timeStyle="medium"):
        <strong>
           <fmt:formatDate type="both" dateStyle="medium" timeStyle="medium" value="${now}" />
        </strong>
     </p>
     <p>
        Date, Time Long (fmt:formatDate type="both" dateStyle="long" timeStyle="long"):
        <strong>
           <fmt:formatDate type="both" dateStyle="long" timeStyle="long" value="${now}" />
        </strong>
     </p>
     <p>
        Date, Time (dd-MM-yyyy HH:mm:ss):
        <strong>
           <fmt:formatDate pattern="dd-MM-yyyy HH:mm:ss" value="${now}" />
        </strong>
     </p>
     
     <!-- Store in variable -->
     <fmt:formatDate pattern="dd-MM-yyyy HH:mm" value="${now}" var="nowString"/>
     
      <p>
        Now String (dd-MM-yyyy HH:mm):
        <strong>
           <c:out value="${nowString}" />
        </strong>
      </p>    
  </body>
</html>
Running the example:

10.4- fmt:parseDate

The <fmt:parseDate> tag parses the string representation of date or time.
Syntax:
<fmt:parseDate
   value="<string>"
   type="<string>"
   dateStyle="<string>"
   timeStyle="<string>"
   pattern="<string>"
   timeZone="<string>"
   parseLocale="<string>"
   var="<string>"
   scope="<string>"/>

Attributes:

Name

Required

Type

Default

Description

value

False

String

Body

The date string to be parsed.

type

False

String

date

Determines whether value specified in the value attribute contains a date, time or both.

dateStyle

False

String

default

Specifies date style (SHORT, LONG, FULL, MEDIUM or DEFAULT).

timeStyle

False

String

default

Specifies time style (SHORT, LONG, FULL, MEDIUM or DEFAULT).

pattern

False

String

 

Specifies the pattern on how the date string to be parsed.

timeZone

False

String

Default time zone

Time zone to interpret if date string contains any time information.

parseLocale

False

String

Default Locale

Locale whose date time formatting will be used to parse the date time.

var

False

String

Print to Page

Name of the variable to store the parsed result.

scope

False

String

page

Scope to store the var.

fmt_parseDate.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>  
<!DOCTYPE html>
<html>
  <head>
     <meta charset="UTF-8">
     <title>fmt:parseDate example</title>
  </head>
  <body>
     <h2>fmt:parseDate example</h2>
     <!-- a Date time string -->  
 
     <c:set var="dateTimeString" value="17-11-2015 11:49" />
     <h4>
        dateTimeString:
        <c:out value="${dateTimeString}"/>
     </h4>
 
     <!-- Parsing a date time string, and store in a variable type of java.util.Date -->
     <fmt:parseDate value="${dateTimeString}"
        type="both" var="parsedDatetime" pattern="dd-MM-yyyy HH:mm" />
     <p>
        The date time after parsing:
        <c:out value="${parsedDatetime}" />
     </p>
     <br/>
     <p>
        Date only (dd/MM/yyyy):
        <fmt:formatDate value="${parsedDatetime}" pattern="dd/MM/yyyy"/>
  </body>

</html>
Running the example:

10.5- fmt:bundle

The <fmt:bundle> tag loads the resource bundle to be used in the page. The resource bundle this tag loads contains the key-value pairs which are used to internationalize or localize the web application. Subsequently, the tag <fmt:message> is used to display the internationalized or localized messages specified in the resource bundle to the output.
Syntax:
<fmt:bundle baseName="<string>" prefix="<string>"/>

Attributes:

Name

Required

Type

Default

Description

baseName

True

String

 

Resource bundle’s fully qualified name. Follows the Java’s fully qualified class name convention (‘.’ is used to separate the package names). For example: org.o7planning.MyBundle.

prefix

False

String

 

When used with <fmt:message> this attribute specifies the value to be prepended in the key value so that each time we do not have to provide the prefix repeatedly.

Using the <fmt:bundle> and <fmt:message> can help your website displayed in multiple languages. Consider the following example:
Create three properties files, in org.o7planning.bundles package.
With content:
MyBundle.properties & MyBundle_en.properties
login.label.userName=User Name
login.label.password=Password
MyBundle_vi.properties
login.label.userName=Tên \u0111\u0103ng nh\u1EADp
login.label.password=M\u1EADt kh\u1EA9u

Unfortunately, when .properties files are read via a ResourceBundle, It has always been read with encoding 'ISO-8859-1'. You can not use Unicode in file properties.  The usual approach is to unicode-escape the non-ascii characters in the properties file. Then it will look something like that:

  • login.label.password=M\u1EADt kh\u1EA9u
When you type Unicode characters in file properties in the "Properties File Editor" of Eclipse, it automatically replaces the non-unicode characters.
fmt_bundle.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>  
<c:if test="${not empty param.language}">
  <c:set var="language" value="${param.language}" scope="session"/>
</c:if>
<fmt:setLocale value="${language}" />
<fmt:setBundle basename="org.o7planning.bundles.MyBundle" />
<!DOCTYPE html>
<html>
  <head>
     <meta charset="UTF-8">
     <title>fmt:bundle example</title>
  </head>
  <body>
     <h2>fmt:bundle example</h2>
     <form action="">
        <table border="0">
           <tr>
              <td>
                 <fmt:message key="login.label.userName"/>
              </td>
              <td>
                 <input type="text" name="userName" />
              </td>
           </tr>
           <tr>
              <td>
                 <fmt:message key="login.label.password"/>
              </td>
              <td><input type="text" name="userName" /></td>
           </tr>
        </table>
        <input type="submit"  value="Submit"/>
     </form>
  </body>
</html>
Running the example:
Note:
<!--
If the user has used one language on a page,
variable 'language' in 'session' scope, its value will stored in user session,
and the website will be displayed in that language,
if the parameters of the page does not specify different values for it.
-->

<c:set var="language" value="${param.language}" scope="session"/>

<fmt:setLocale value="${language}" />

10.6- fmt:message

The <fmt:message> is used to display the localized messages by replacing the key specified, with the actual message loaded from the resource bundle. This tag works in conjunction with <fmt:bundle> tag which is used to load the resource bundle.
Syntax:
<fmt:message
   key="<string>"
   bundle="<string>"
   var="<string>"
   scope="<string>"/>

Attributes:

Name

Required

Type

Default

Description

key

False

String

Body

Key of the message to be looked up from the resource bundle.

bundle

False

String

Default bundle

Which resource bundle the key to be looked up.

var

False

String

Print to Page

Name of the variable to store the localized message.

scope

False

String

page

The scope in which the localized message variable to be stored.