問題描述
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.1.xsd">
<context:component-scan
base-package="com.springinaction.chapter01.knight" />
</beans>
上面的例子顯示了一個帶有多個命名空間的 XML 文件的例子.這些名稱空間的目的是什么?最重要的是，為什么即使在沒有 Internet 連接的情況下它們也能工作?
The above example shows an example of an XML file with several namespaces. What is the purpose of these namespaces and most importantly why do they work even where there is no Internet connection?
我認為以 xsi:schemaLocation 開頭的第二位包含用于驗證 XML 文檔結構的 XML 模式文件.如果我在不在網絡上的機器上運行使用此配置文件的應用程序，這些為什么仍然有效?這些 URL 是否是 JAR 文件的別名?
I think the second bit that starts with xsi:schemaLocation contains the XML schema files which are used to validate the structure of the XML document. How come these still work if I run the application that uses this configuration file on a machine that is not on a network? Are the URLs somehow aliases to JAR files?
推薦答案
假設我們有這個 XML 文檔.
Let us assume we have this XML document.
<?xml version="1.0" encoding="UTF-8"?>
<html>
<body>
Your text here
</body>
<body>
<height>182 cm</height>
<weight>83 kg</weight>
</body>
</html>
它包括 HTML，它有一個帶有 HTML 渲染器語義含義的 body 標簽.它還有另一個身體標簽，其中包含有關特定人的信息.命名空間定義了這個標簽的語義范圍.如果沒有命名空間(如提供的示例中所示)，解析器就不可能區分它們，因為它們在語法上是相同的.
It includes HTML which has a body tag with a semantic meaning for a HTML renderer. It also has another body tag which carries information about a specific person. A namespace defines a semantic scope for this tag. Without a namespace(as in the example provided), it is impossible for a parser to tell the difference because they are syntactically the same.
這是同一文檔的語義正確版本:
Here is the semantically correct version of the same document:
<?xml version="1.0" encoding="UTF-8"?>
<html:html xmlns:html="http://www.w3.org/TR/xhtml1/">
<html:body>
Your text here
</html:body>
<human:body xmlns:human="http://www.example.com/human/">
<human:height>182 cm</human:height>
<human:weight>83 kg</human:weight>
</human:body>
</html:html>
因此，多虧了命名空間，我們不必擔心具有不同含義的標簽沖突.
Thus thanks to namespaces we do not have worry about conflicting tags with different meanings.
命名空間 URI 本身從未真正解析過，并且是任意的(因此您可以離線使用它們).
The namespace URIs themselves are never actually resolved, and are arbitrary (thus you can use them offline).
這篇關于XML 命名空間如何在沒有工作網絡連接的情況下工作?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！