JSP之JSTL_functions

  1 <?xml version="1.0" encoding="UTF-8" ?>
  2 
  3 <taglib xmlns="http://java.sun.com/xml/ns/j2ee"
  4 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  5 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
  6 version="2.0">
  7     
  8 <description>JSTL 1.1 functions library</description>
  9 <display-name>JSTL functions</display-name>
 10 <tlib-version>1.1</tlib-version>
 11 <short-name>fn</short-name>
 12 <uri>http://java.sun.com/jsp/jstl/functions</uri>
 13 
 14 <function>
 15     <description>
 16       Tests if an input string contains the specified substring.
 17     </description>
 18     <name>contains</name>
 19     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
 20     <function-signature>boolean contains(java.lang.String, java.lang.String)</function-signature>
 21     <example>
 22       &lt;c:if test="${fn:contains(name, searchString)}">
 23     </example>
 24 </function>
 25 
 26 <function>
 27     <description>
 28       Tests if an input string contains the specified substring in a case insensitive way.
 29     </description>
 30     <name>containsIgnoreCase</name>
 31     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
 32     <function-signature>boolean containsIgnoreCase(java.lang.String, java.lang.String)</function-signature>
 33     <example>
 34       &lt;c:if test="${fn:containsIgnoreCase(name, searchString)}">
 35     </example>
 36 </function>
 37 
 38 <function>
 39     <description>
 40       Tests if an input string ends with the specified suffix.
 41     </description>
 42     <name>endsWith</name>
 43     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
 44     <function-signature>boolean endsWith(java.lang.String, java.lang.String)</function-signature>
 45     <example>
 46       &lt;c:if test="${fn:endsWith(filename, ".txt")}">
 47     </example>
 48 </function>
 49 
 50 <function>
 51     <description>
 52       Escapes characters that could be interpreted as XML markup.
 53     </description>
 54     <name>escapeXml</name>
 55     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
 56     <function-signature>java.lang.String escapeXml(java.lang.String)</function-signature>
 57     <example>
 58       ${fn:escapeXml(param:info)}
 59     </example>
 60 </function>
 61 
 62 <function>
 63     <description>
 64       Returns the index withing a string of the first occurrence of a specified substring.
 65     </description>
 66     <name>indexOf</name>
 67     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
 68     <function-signature>int indexOf(java.lang.String, java.lang.String)</function-signature>
 69     <example>
 70       ${fn:indexOf(name, "-")}
 71     </example>
 72 </function>
 73 
 74 <function>
 75     <description>
 76       Joins all elements of an array into a string.
 77     </description>
 78     <name>join</name>
 79     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
 80     <function-signature>java.lang.String join(java.lang.String[], java.lang.String)</function-signature>
 81     <example>
 82       ${fn:join(array, ";")}
 83     </example>
 84 </function>
 85 
 86 <function>
 87     <description>
 88       Returns the number of items in a collection, or the number of characters in a string.
 89     </description>
 90     <name>length</name>
 91     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
 92     <function-signature>int length(java.lang.Object)</function-signature>
 93     <example>
 94       You have ${fn:length(shoppingCart.products)} in your shopping cart.
 95     </example>
 96 </function>
 97 
 98 <function>
 99     <description>
100       Returns a string resulting from replacing in an input string all occurrences
101       of a "before" string into an "after" substring.
102     </description>
103     <name>replace</name>
104     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
105     <function-signature>java.lang.String replace(java.lang.String, java.lang.String, java.lang.String)</function-signature>
106     <example>
107       ${fn:replace(text, "-", "&#149;")}
108     </example>
109 </function>
110 
111 <function>
112     <description>
113       Splits a string into an array of substrings.
114     </description>
115     <name>split</name>
116     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
117     <function-signature>java.lang.String[] split(java.lang.String, java.lang.String)</function-signature>
118     <example>
119       ${fn:split(customerNames, ";")}
120     </example>
121 </function>
122 
123 <function>
124     <description>
125       Tests if an input string starts with the specified prefix.
126     </description>
127     <name>startsWith</name>
128     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
129     <function-signature>boolean startsWith(java.lang.String, java.lang.String)</function-signature>
130     <example>
131       &lt;c:if test="${fn:startsWith(product.id, "100-")}">
132     </example>
133 </function>
134 
135 <function>
136     <description>
137       Returns a subset of a string.
138     </description>
139     <name>substring</name>
140     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
141     <function-signature>java.lang.String substring(java.lang.String, int, int)</function-signature>
142     <example>
143       P.O. Box: ${fn:substring(zip, 6, -1)}
144     </example>
145 </function>
146 
147 <function>
148     <description>
149       Returns a subset of a string following a specific substring.
150     </description>
151     <name>substringAfter</name>
152     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
153     <function-signature>java.lang.String substringAfter(java.lang.String, java.lang.String)</function-signature>
154     <example>
155       P.O. Box: ${fn:substringAfter(zip, "-")}
156     </example>
157 </function>
158 
159 <function>
160     <description>
161       Returns a subset of a string before a specific substring.
162     </description>
163     <name>substringBefore</name>
164     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
165     <function-signature>java.lang.String substringBefore(java.lang.String, java.lang.String)</function-signature>
166     <example>
167       Zip (without P.O. Box): ${fn:substringBefore(zip, "-")}
168     </example>
169 </function>
170 
171 <function>
172     <description>
173       Converts all of the characters of a string to lower case.
174     </description>
175     <name>toLowerCase</name>
176     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
177     <function-signature>java.lang.String toLowerCase(java.lang.String)</function-signature>
178     <example>
179       Product name: ${fn:toLowerCase(product.name)}
180     </example>
181 </function>
182 
183 <function>
184     <description>
185       Converts all of the characters of a string to upper case.
186     </description>
187     <name>toUpperCase</name>
188     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
189     <function-signature>java.lang.String toUpperCase(java.lang.String)</function-signature>
190     <example>
191       Product name: ${fn:UpperCase(product.name)}
192     </example>
193 </function>
194 
195 <function>
196     <description>
197       Removes white spaces from both ends of a string.
198     </description>
199     <name>trim</name>
200     <function-class>org.apache.taglibs.standard.functions.Functions</function-class>
201     <function-signature>java.lang.String trim(java.lang.String)</function-signature>
202     <example>
203       Name: ${fn:trim(name)}
204     </example> 
205 </function>
206 
207 </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..