JSTL 1.2 II8n Tag LibraryS2C Home « JSTL 1.2 II8n Tag Library

In our third lesson on JSTL 1.2 tag libraries we look at the II8n tag library. The II8n tag library consists of actions that allow us to format and internationalise currencies, numbers, percentages, dates and times.

Each II8n action can have mandatory attributes that have to be populated and each attribute may also allow a run-time expression to be used. If a run-time expression is allowed for an attribute this can be populated using a static string or more interestingly a dynamic value which can be an EL or Java expression or a value set using the <jsp:attribute> standard action. If no run-time expression is allowed for an attribute then you can only populate that attribute using a static string.

Number II8n Actionsgo to top of page Top

There are two number II8n actions for formatting and parsing numbers, these being <fmt:formatNumber> which allows us to format a currency, number or percentage to our specifications and <fmt:parseNumber> which allows us to parse a string representation of currency, number or percentage.

Action /
Attribute Name
Mandatory Run-time Expression? Default Value Object Type Description
<fmt:formatNumber>
valueYesYesNoneString or NumberNumeric value to be formatted.
typeNoYesnumberStringSpecify whether value is to be formatted as a number, currency or percent.
patternNoYesNoneStringCustom pattern for formatting.
currencyCodeNoYesNoneStringISO 4217 1 currency code which is only applicable when type attribute is 'currency', otherwise this attribute is ignored.
currencySymbolNoYesNoneStringISO 4217 1 currency symbol which is only applicable when type attribute is 'currency', otherwise this attribute is ignored.
groupingUsedNoYestruebooleanSpecifies whether formatted output will contain grouping separators.
maxIntegerDigitsNoYesNoneintMaximum number of digits in integer portion of the formatted output.
minIntegerDigitsNoYesNoneintMinimum number of digits in integer portion of the formatted output.
maxFractionDigitsNoYesNoneintMaximum number of digits in fractional portion of the formatted output.
minFractionDigitsNoYesNoneintMinimum number of digits in fractional portion of the formatted output.
varNoNoNoneStringName of exported scoped variable to hold expression value.
The type of scoped variable is String.
scopeNoNopageStringScope that the created scoped variable var exists in.
<fmt:parseNumber>
valueNoYesNoneStringString value to be parsed.
typeNoYesnumberStringSpecify whether value is to be formatted as a number, currency or percent.
patternNoYesNoneStringCustom pattern for formatting string value held within the value attribute.
parseLocaleNoYesNoneStringLocale whose default formatting pattern is to be used during the parse operation, or to which the pattern specified via pattern attribute is applied.
integerOnlyNoYestruebooleanSpecifies whether just the integer portion of the given value should be parsed.
varNoNoNoneStringName of exported scoped variable to hold expression value.
The type of scoped variable is Number.
scopeNoNopageStringScope that the created scoped variable var exists in.

1: For a full list of valid ISO 4217 codes follow this wikipedia link.

<fmt:formatNumber>go to top of page Top

The <fmt:formatNumber> tag formats a numeric value in a locale-sensitive or customized manner as a number, currency, or percentage.

The numeric value to be formatted can be specified using the value attribute or when omitted read from <fmt:formatNumber> tag’s body content. The formatting pattern may be specified via the pattern attribute and if present takes precedence over the type attribute and must adhere to the pattern syntax rules spcifed in the java.text.DecimalFormat class.

Formatted results using the <fmt:formatNumber> tag are output to the current JspWriter object, unless the var attribute is specified, in which case formatted results are stored in the named scoped variable.

The following code snippets shows the two variants of the <fmt:formatNumber> tag where the square brackets indicate optional attributes and the curly bracers indicate a choice of options within them where the default is underlined.


// No body content
<fmt:formatNumber value="numericValue" [type="{number|currency|percent}"] [pattern="customPattern"]
        [currencyCode="currencyCode"] [currencySymbol="currencySymbol"] [groupingUsed="{true|false}"] 
        [maxIntegerDigits="maxIntegerDigits"] [minIntegerDigits="minIntegerDigits"] 
        [maxFractionDigits="maxFractionDigits"] [minFractionDigits="minFractionDigits"] 
        [var="varName"] [scope="{page|request|session|application}"] />

// Body content specifying numeric value to be formatted
<fmt:formatNumber [type="{number|currency|percent}"] [pattern="customPattern"]
        [currencyCode="currencyCode"] [currencySymbol="currencySymbol"] [groupingUsed="{true|false}"] 
        [maxIntegerDigits="maxIntegerDigits"] [minIntegerDigits="minIntegerDigits"] 
        [maxFractionDigits="maxFractionDigits"] [minFractionDigits="minFractionDigits"] 
        [var="varName"] [scope="{page|request|session|application}"] >
    numeric value to be formatted
</fmt:formatNumber>

<fmt:parseNumber>go to top of page Top

The <fmt:parseNumber> tag parses the string representation of numbers, currencies, and percentages that were formatted in a locale-sensitive or customized manner.

The numeric value to be parsed can be specified using the value attribute or when omitted read from <fmt:parseNumber> tag’s body content. The formatting pattern may be specified via the pattern attribute and if present takes precedence over the type attribute and must adhere to the pattern syntax rules spcifed in the java.text.DecimalFormat class.

Formatted results using the <fmt:parseNumber> tag are output to the current JspWriter object using java.lang.Number.toString(), unless the var attribute is specified, in which case formatted results are stored in the named scoped variable.

The following code snippets shows the two variants of the <fmt:parseNumber> tag where the square brackets indicate optional attributes and the curly bracers indicate a choice of options within them where the default is underlined.


// No body content
<fmt:parseNumber value="numericValue" [type="{number|currency|percent}"] [pattern="customPattern"]
        [parseLocale="parseLocale"] [integerOnly="{true|false}"] 
        [var="varName"] [scope="{page|request|session|application}"] />

// Body content specifying numeric value to be parsed
<fmt:parseNumber [type="{number|currency|percent}"] [pattern="customPattern"]
        [parseLocale="parseLocale"] [integerOnly="{true|false}"] 
        [var="varName"] [scope="{page|request|session|application}"] >
    numeric value to be parsed
</fmt:parseNumber>

Number II8n Examplesgo to top of page Top

The following code shows examples of using general purpose tags within the Core tag library.


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

<%-- Output formatted number --%>
Number: <fmt:formatNumber value="123456789" /><br />
<%-- Output formatted number with maximum fraction digits --%>
Maximum Fraction Number: <fmt:formatNumber value="123456789" maxIntegerDigits="6" /><br />
<%-- Output formatted number with minimum digits --%>
Minimum Digits Number: <fmt:formatNumber value="123456789" minFractionDigits="3" /><br />
<%-- Output formatted number using a pattern --%>
Pattern Number: <fmt:formatNumber value="123456.789" pattern="#,#00.0#" /><br />
<%-- Output formatted number with default currency type --%>
Default Currency: <fmt:formatNumber value="12345" type="currency" /><br />
<%-- Output formatted number with Japanese currency type --%>
Japanese Currency: <fmt:formatNumber value="12345" type="currency" currencyCode="JPY" /><br />
<%-- Output precentage number--%>
Percentage: <fmt:formatNumber value="45" type="percent" /><br />

The following screnshot shows the results of running the above JSP code.

Core Tags

Date II8n Actionsgo to top of page Top

There are two date II8n actions for formatting and parsing dates, these being <fmt:formatDate> which allows us to format a dates to our specifications and <fmt:parseDate> which allows us to parse a string representation of a date and time in locale-sensitive format.

Action /
Attribute Name
Mandatory Run-time Expression? Default Value Object Type Description
<fmt:formatDate>
valueYesYesNonejava.util.DateDate and/or time to be formatted.
typeNoYesdateStringSpecify whether value is to be formatted as a date or time or both.
dateStyleNoYesdefaultStringPredefined formatting style for dates that follow the semantics defined in java.text.DateFormat.
timeStyleNoYesdefaultStringPredefined formatting style for times that follow the semantics defined in java.text.DateFormat.
patternNoYesNoneStringCustom pattern for formatting dates and times.
timeZoneNoYesNoneString or java.util.TimeZoneThe time zone used to represent the time.
varNoNoNoneStringName of exported scoped variable to hold expression value.
The type of scoped variable is String.
scopeNoNopageStringScope that the created scoped variable var exists in.
<fmt:parseDate>
valueYesYesNonejava.util.DateDate and/or time to be formatted.
typeNoYesdateStringSpecify whether value is to be formatted as a date or time or both.
dateStyleNoYesdefaultStringPredefined formatting style for dates that follow the semantics defined in java.text.DateFormat.
timeStyleNoYesdefaultStringPredefined formatting style for times that follow the semantics defined in java.text.DateFormat.
patternNoYesNoneStringCustom pattern for formatting dates and times.
timeZoneNoYesNoneString or java.util.TimeZoneThe time zone used to represent the time.
parseLocaleNoYesNoneString or java.util.LocaleLocale whose predefined formatting styles are to be used during the parse operation, or to which any present pattern attribute is applied.
varNoNoNoneStringName of exported scoped variable to hold expression value.
The type of scoped variable is String.
scopeNoNopageStringScope that the created scoped variable var exists in.

<fmt:formatDate>go to top of page Top

The <fmt:formatDate> tag allows us to which allows us to format a dates to our specifications or to locale-sensitive formats.

If the scope attribute is specified the var attribute must also be specified. If the value attribute is null or empty, nothing is written to the current JspWriter object and any scoped variable specified is removed. If the timeZone attribute is null or empty, it is handled as if it wasn't specified.

If the <fmt:formatDate> tag fails to determine a formatting locale, it uses java.util.Date.toString() for formatting any output.

The following code snippet shows the syntax of the <fmt:formatDate> tag where the square brackets indicate optional attributes and the curly bracers indicate a choice of options within them where the default is underlined.


// Format a date
<fmt:formatDate value="date" [type="{date|time|both}"] 
        [dateStyle="{default|short|medium|long|full}"]
        [timeStyle="{default|short|medium|long|full}"]
        [pattern="customPattern"] [timezone="timezone"]
        [var="varName"] [scope="{page|request|session|application}"] />

<fmt:parseDate>go to top of page Top

The <fmt:parseDate> tag is used to parse the string representation of dates and times that were formatted in a locale-sensitive or customized manner.

If the date string to be parsed is null or empty, the scoped variable defined by var and scope are removed, allowing "empty" input to be distinguished from "invalid" input, which causes an exception. If the timeZone attribute is null or empty, it is handled as if it wasn't specified. If the parseLocale attribute is null or empty, it is handled as if it wasn't specified. If an exception occurs during parsing of the value, it must be caught and rethrown as a JspException.

If the <fmt:formatDate> tag fails to determine a formatting locale, it uses java.util.Date.toString() for formatting any output.

There are two variants of the <fmt:parseDate> tag, with or without a body, as shown in the code snippets below:


// No body content
<fmt:parseDate value="dateString" [type="{date|time|both}"]
        [dateStyle="{default|short|medium|long|full}"]
        [timeStyle="{default|short|medium|long|full}"]
        [pattern="customPattern"] [timezone="timezone"] [parseLocale="parseLocale"]
        [var="varName"] [scope="{page|request|session|application}"] />

// Body content specifying date value to be parsed
<fmt:parseDate [type="{date|time|both}"]
        [dateStyle="{default|short|medium|long|full}"]
        [timeStyle="{default|short|medium|long|full}"]
        [pattern="customPattern"] [timezone="timezone"] [parseLocale="parseLocale"]
        [var="varName"] [scope="{page|request|session|application}"] >
    numeric value to be parsed
</fmt:parseDate>

Date II8n Examplesgo to top of page Top

The following code shows examples of using general purpose tags within the Core tag library.


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

<%-- Get current date and time --%>
<jsp:useBean id="now" class="java.util.Date" />
<%-- Output formatted date --%>
Current Date: <fmt:formatDate value="${now}" /><br />
<%-- Output formatted time --%>
Current Time: <fmt:formatDate value="${now}" type="time" /><br />
<%-- Output formatted date and time --%>
Current Date and Time: <fmt:formatDate value="${now}" type="both" /><br />
<%-- Output long date --%>
Current Long Date: <fmt:formatDate value="${now}" dateStyle="long" /><br />
<%-- Output full time --%>
Current Full Time: <fmt:formatDate value="${now}" type="time" timeStyle="full" /><br />

The following screnshot shows the results of running the above JSP code.

Core Tags

Time Zone II8n Actionsgo to top of page Top

There are two time zone II8n actions, these being <fmt:timeZone> action which allows us to specify the time zone in which time information is to be formatted or parsed in its body content and the <fmt:setTimeZone> action which allows us to store the specified time zone in either a scoped variable or the time zone configuration variable.

Action /
Attribute Name
Mandatory Run-time Expression? Default Value Object Type Description
<fmt:timeZone>
valueYesYesNoneString or
java.util.TimeZone
The time zone where a string value is interpreted as a time zone ID.
<fmt:setTimeZone>
valueYesYesNoneString or
java.util.TimeZone
The time zone where a string value is interpreted as a time zone ID.
varNoNoNoneStringName of exported scoped variable to hold expression value.
The type of scoped variable is java.util.TimeZone.
scopeNoNopageStringScope that the created scoped variable var exists in.

<fmt:timeZone>go to top of page Top

The <fmt:timeZone> action allows us to specify the time zone in which time information is to be formatted or parsed in its body content.

The following code snippets shows the syntax of the <fmt:timeZone> tag.


// Specify time zone
<fmt:timeZone value="timeZone" >
    body content
</fmt:timeZone>

<fmt:setTimeZone>go to top of page Top

The <fmt:setTimeZone> tag allows us to store the specified time zone in either a scoped variable or the time zone configuration variable.

The following code snippets shows the syntax of the <fmt:setTimeZone> tag.


// Store time zone
<fmt:setTimeZone value="timeZone" [var="varName"] [scope="{page|request|session|application}"] />

Time Zone II8n Examplesgo to top of page Top

The following code shows examples of using general purpose tags within the Core tag library.


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

<%-- Get time --%>
<jsp:useBean id="now" class="java.util.Date" />
<%-- Specify time zone US Eastern Standard Time and output current date --%>
<fmt:timeZone value="EST" >
  Current Full Date and Time EST: <fmt:formatDate value="${now}" type="both" 
      dateStyle="full" timeStyle="full" />
</fmt:timeZone>

The following screnshot shows the results of running the above JSP code.

Core Tags

Lesson 4 Complete

In our third lesson on JSTL tag libraries we looked at the Ii8n tag library.

What's Next?

In our fourth lesson on JSTL tag libraries we look at the Database tag library.

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