Java - 读取 XML 并留下所有实体 [英] Java - Read XML and leave all entities alone
问题描述
我想使用 SAX 或 StAX 读取 XHTML 文件，无论哪种效果最好.但我不希望实体被解析、替换或类似的事情.理想情况下，它们应该保持原样.我不想使用 DTD.
I want to read XHTML files using SAX or StAX, whatever works best. But I don't want entities to be resolved, replaced or anything like that. Ideally they should just remain as they are. I don't want to use DTDs.
这是一个(可执行文件，使用 Scala 2.8.x)示例:
Here's an (executable, using Scala 2.8.x) example:
import javax.xml.stream._
import javax.xml.stream.events._
import java.io._
println("StAX Test - "+args(0)+"\n")
val factory = XMLInputFactory.newInstance
factory.setProperty(XMLInputFactory.SUPPORT_DTD, false)
factory.setProperty(XMLInputFactory.IS_REPLACING_ENTITY_REFERENCES, false)
println("------")
val xer = factory.createXMLEventReader(new FileReader(args(0)))
val entities = new collection.mutable.ArrayBuffer[String]
while (xer.hasNext) {
val event = xer.nextEvent
if (event.isCharacters) {
print(event.asCharacters.getData)
} else if (event.getEventType == XMLStreamConstants.ENTITY_REFERENCE) {
entities += event.asInstanceOf[EntityReference].getName
}
}
println("------")
println("Entities: " + entities.mkString(", "))
给定以下 xhtml 文件...
Given the following xhtml file ...
<html>
<head>
<title>StAX Test</title>
</head>
<body>
<h1>Hallo StAX</h1>
<p id="html">
<div class="header">
</p>
<p id="stuff">
Überdies sollte das hier auch als Copyright sichtbar sein: ©
</p>
Das war's!
</body>
</html>
... 运行 scala stax-test.scala stax-test.xhtml 将导致:
... running scala stax-test.scala stax-test.xhtml will result in:
StAX Test - stax-test.xhtml
------
StAX Test
Hallo StAX
<div class="header">
berdies sollte das hier auch als Copyright sichtbar sein: ?
Das war's!
------
Entities: Uuml
因此，所有实体或多或少都已成功替换.不过，我所期望的和我想要的是:
So all entities have been replaced more or less sucessfully. What I would have expected and what I want is this, though:
StAX Test - stax-test.xhtml
------
StAX Test
Hallo StAX
<div class="header">
Überdies sollte das hier auch als Copyright sichtbar sein: ©
Das war's!
------
Entities: // well, or no entities above and instead:
// Entities: lt, quot, quot, gt, Uuml, #169
这甚至可能吗?我想解析 XHTML，做一些修改，然后再次将它输出为 XHTML.所以我真的希望实体保留在结果中.
Is this even possible? I want to parse XHTML, do some modifications and then output it like that as XHTML again. So I really want the entities to remain in the result.
我也不明白为什么 Uuml 被报告为 EntityReference 事件，而其余的则不是.
Also I don't get why Uuml is reported as an EntityReference event while the rest aren't.
推荐答案
一些术语:ũ 是数字字符引用(不是实体)，而 &#auml; 是实体引用(不是实体).
A bit of terminology: ũ is a numeric character reference (not an entity), and &#auml; is an entity reference (not an entity).
我认为任何 XML 解析器都不会报告对应用程序的数字字符引用——它们总是会被扩展.实际上，您的应用程序不应该关心这一点，就像关心属性之间有多少空白一样.
I don't think any XML parser will report numeric character references to the application - they will always be expanded. Really, your application shouldn't care about this any more than it cares about how much whitespace there is between attributes.
至于实体引用，SAX 等低级解析接口会报告实体引用的存在——无论如何，当它们出现在元素内容中时，它会报告它们，但不会在属性内容中报告它们.有一些特殊事件只通知给 LexicalHandler 而不是 ContentHandler.
As for entity references, low-level parse interfaces such as SAX will report the existence of the entity reference - at any rate, it reports them when they occur in element content, but not in attribute content. There are special events notified only to the LexicalHandler rather than to the ContentHandler.
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