如何使用JSP/JSTL解析URL? [英] How can I parse a URL using JSP/JSTL?
问题描述
我想捕获给定网址的基本路径
I want to capture the base path of a given url
http://mydomain.com/mypath/coolpath/favoritepath/file.htm
所以基本上我只想要这个:
so basically i just want this:
/mypath/coolpath/favoritepath/
/mypath/coolpath/favoritepath/
有没有在不使用直接Java的情况下如何做到这一点的想法?
Any ideas how to do this without using straight Java?
推荐答案
此功能在JSTL中不存在.最接近的是fn:replace()
,但它不支持正则表达式.其他功能提供了直到域为止都可以除去前导部分(在//
和/
上多次使用fn:substringAfter()
),但是没有什么可以轻易除去尾随部分.也许有很多fn:substringAfter
和c:set
循环在一起,但这会使代码笨拙并且不能真正重用.
This functionality doesn't exist in JSTL. Closest is the fn:replace()
, but it doesn't support regular expressions. The other functions provides the possibility to get rid of the leading part until with the domain (using fn:substringAfter()
a several times on //
and /
), but there's nothing which makes it easy to get rid of the trailing part. Maybe with a whole bunch of fn:substringAfter
and c:set
in a loop, but it would make the code clumsy and not really reuseable.
好吧,在正则表达式中,您可以使用^[^/]+/+[^/]+|[^/]+$
进行此操作:
Well, in regex you could use ^[^/]+/+[^/]+|[^/]+$
for this:
url = url.replaceAll("^[^/]+/+[^/]+|[^/]+$", "");
您可以创建一个自定义的EL函数来完成此任务:
You could create a custom EL function which does exactly this:
${f:replaceAll(url, '^[^/]+/+[^/]+|[^/]+$', '')}
要实现这一点,首先创建一个像这样的类:
To achieve this, first create a class like this:
package com.example;
public final class Functions {
private Functions() {}
public static String replaceAll(String string, String pattern, String replacement) {
return string.replaceAll(pattern, replacement);
}
}
并创建如下的/WEB-INF/functions.tld
:
<?xml version="1.0" encoding="UTF-8" ?>
<taglib
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd"
version="2.1">
<display-name>Custom Functions</display-name>
<tlib-version>1.0</tlib-version>
<uri>http://example.com/functions</uri>
<function>
<name>matches</name>
<function-class>com.example.Functions</function-class>
<function-signature>java.lang.String replaceAll(java.lang.String, java.lang.String, java.lang.String)</function-signature>
</function>
</taglib>
您可以将其导入为:
<%@taglib uri="http://example.com/functions" prefix="f" %>
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