<?xml version="1.0" encoding="UTF-8" ?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
version="2.0">
<description>JSTL 1.1 functions library</description>
<display-name>JSTL functions</display-name>
<tlib-version>1.1</tlib-version>
<short-name>fn</short-name>
<uri>http://java.sun.com/jsp/jstl/functions</uri>
<function>
<description>
Tests if an input string contains the specified substring.
</description>
<name>contains</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>boolean contains(java.lang.String, java.lang.String)</function-signature>
<example>
<c:if test="${fn:contains(name, searchString)}">
</example>
</function>
<function>
<description>
Tests if an input string contains the specified substring in a case insensitive way.
</description>
<name>containsIgnoreCase</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>boolean containsIgnoreCase(java.lang.String, java.lang.String)</function-signature>
<example>
<c:if test="${fn:containsIgnoreCase(name, searchString)}">
</example>
</function>
<function>
<description>
Tests if an input string ends with the specified suffix.
</description>
<name>endsWith</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>boolean endsWith(java.lang.String, java.lang.String)</function-signature>
<example>
<c:if test="${fn:endsWith(filename, ".txt")}">
</example>
</function>
<function>
<description>
Escapes characters that could be interpreted as XML markup.
</description>
<name>escapeXml</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String escapeXml(java.lang.String)</function-signature>
<example>
${fn:escapeXml(param:info)}
</example>
</function>
<function>
<description>
Returns the index withing a string of the first occurrence of a specified substring.
</description>
<name>indexOf</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>int indexOf(java.lang.String, java.lang.String)</function-signature>
<example>
${fn:indexOf(name, "-")}
</example>
</function>
<function>
<description>
Joins all elements of an array into a string.
</description>
<name>join</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String join(java.lang.String[], java.lang.String)</function-signature>
<example>
${fn:join(array, ";")}
</example>
</function>
<function>
<description>
Returns the number of items in a collection, or the number of characters in a string.
</description>
<name>length</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>int length(java.lang.Object)</function-signature>
<example>
You have ${fn:length(shoppingCart.products)} in your shopping cart.
</example>
</function>
<function>
<description>
Returns a string resulting from replacing in an input string all occurrences
of a "before" string into an "after" substring.
</description>
<name>replace</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String replace(java.lang.String, java.lang.String, java.lang.String)</function-signature>
<example>
${fn:replace(text, "-", "•")}
</example>
</function>
<function>
<description>
Splits a string into an array of substrings.
</description>
<name>split</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String[] split(java.lang.String, java.lang.String)</function-signature>
<example>
${fn:split(customerNames, ";")}
</example>
</function>
<function>
<description>
Tests if an input string starts with the specified prefix.
</description>
<name>startsWith</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>boolean startsWith(java.lang.String, java.lang.String)</function-signature>
<example>
<c:if test="${fn:startsWith(product.id, "100-")}">
</example>
</function>
<function>
<description>
Returns a subset of a string.
</description>
<name>substring</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String substring(java.lang.String, int, int)</function-signature>
<example>
P.O. Box: ${fn:substring(zip, 6, -1)}
</example>
</function>
<function>
<description>
Returns a subset of a string following a specific substring.
</description>
<name>substringAfter</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String substringAfter(java.lang.String, java.lang.String)</function-signature>
<example>
P.O. Box: ${fn:substringAfter(zip, "-")}
</example>
</function>
<function>
<description>
Returns a subset of a string before a specific substring.
</description>
<name>substringBefore</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String substringBefore(java.lang.String, java.lang.String)</function-signature>
<example>
Zip (without P.O. Box): ${fn:substringBefore(zip, "-")}
</example>
</function>
<function>
<description>
Converts all of the characters of a string to lower case.
</description>
<name>toLowerCase</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String toLowerCase(java.lang.String)</function-signature>
<example>
Product name: ${fn:toLowerCase(product.name)}
</example>
</function>
<function>
<description>
Converts all of the characters of a string to upper case.
</description>
<name>toUpperCase</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String toUpperCase(java.lang.String)</function-signature>
<example>
Product name: ${fn:UpperCase(product.name)}
</example>
</function>
<function>
<description>
Removes white spaces from both ends of a string.
</description>
<name>trim</name>
<function-class>org.apache.taglibs.standard.functions.Functions</function-class>
<function-signature>java.lang.String trim(java.lang.String)</function-signature>
<example>
Name: ${fn:trim(name)}
</example>
</function>
</taglib>
上述是http://java.sun.com/jsp/jstl/functions的源代码
用来弥补JSTL在处理字符串上的缺陷
使用的方式
一、
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
二、
在WEB-INF目录下创建functions.ltd
然后将上述代码拷进去
<%@ taglib prefix="fn" uri="/WEB-INF/functions.tld" %>
或则
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
区别在于说这样的话即使不联网也可以使用
<!-- 函数说明 -->
| 函数名 | 函数说明 | 使用举例 |
| fn:contains | 判断字符串是否包含另外一个字符串 | <c:if test="${fn:contains(name, searchString)}"> |
| fn:containsIgnoreCase | 判断字符串是否包含另外一个字符串(大小写无关) | <c:if test="${fn:containsIgnoreCase(name, searchString)}"> |
| fn:endsWith | 判断字符串是否以另外字符串结束 | <c:if test="${fn:endsWith(filename, ".txt")}"> |
| fn:escapeXml | 把一些字符转成XML表示，例如<字符应该转为< | ${fn:escapeXml(param:info)} |
| fn:indexOf | 子字符串在母字符串中出现的位置 | ${fn:indexOf(name, "-")} |
| fn:join | 将数组中的数据联合成一个新字符串，并使用指定字符格开 | ${fn:join(array, ";")} |
| fn:length | 获取字符串的长度，或者数组的大小 | ${fn:length(shoppingCart.products)} |
| fn:replace | 替换字符串中指定的字符 | ${fn:replace(text, "-", "•")} |
| fn:split | 把字符串按照指定字符切分 | ${fn:split(customerNames, ";")} |
| fn:startsWith | 判断字符串是否以某个子串开始 | <c:if test="${fn:startsWith(product.id, "100-")}"> |
| fn:substring | 获取子串 | ${fn:substring(zip, 6, -1)} |
| fn:substringAfter | 获取从某个字符所在位置开始的子串 |
${fn:substringAfter(zip, "-")} |
| fn:substringBefore | 获取从开始到某个字符所在位置的子串 | ${fn:substringBefore(zip, "-")} |
| fn:toLowerCase | 转为小写 | ${fn.toLowerCase(product.name)} |
| fn:toUpperCase | 转为大写字符 | ${fn.UpperCase(product.name)} |
| fn:trim | 去除字符串前后的空格 | ${fn.trim(name)} |
其实就是一些JAVA中处理字符串的方法。
end..