我想解析以下 XML 文档以解析其中的所有实体:
<!DOCTYPE doc SYSTEM 'mydoc.dtd'><doc>&title;</doc>
我的 EntityResolver 应该从数据库中获取具有给定系统 ID 的外部实体,然后进行解析,请参见下图:
私有静态类 MyEntityResolver{public InputSource resolveEntity(String publicId, String systemId)抛出 SAXException、IOException{//此时systemId总是被绝对化为当前工作目录,//即使 XML 文档将其指定为相对的.//例如file:///H:/mydoc.dtd" 而不仅仅是mydoc.dtd"//为什么???我怎样才能防止这种情况???SgmlEntity 实体 = findEntityFromDatabase(systemId);InputSource is = new InputSource(new ByteArrayInputStream(entity.getContents()));is.setPublicId(publicId);is.setSystemId(systemId);回报是;}}
我尝试使用 DOM (DocumentBuilder) 和 SAX (XMLReader),将实体解析器设置为 MyEntityResolver(即 setEntityResolver(new MyEntityResolver())
),但 systemId
在 MyEntityResolver#resolveEntity(String publicId, String systemId)
中总是被绝对化到当前工作目录.
我也尝试调用 setFeature("http://xml.org/sax/features/resolve-dtd-uris", false);
,但没有任何帮助.p>
那么我怎样才能实现我想要的呢?
谢谢!
显然还有一个接口叫EntityResolver2 是旧 EntityResolver.(谈论令人困惑的名字!)
无论如何,我发现 EntityResolver2
实现了我想要的,也就是说,它没有对 systemId
进行任何更改,所以它始终是指定的在 XML 文档中.
I want to parse the following XML document to resolve all entities in it:
<!DOCTYPE doc SYSTEM 'mydoc.dtd'>
<doc>&title;</doc>
My EntityResolver is supposed to fetch the external entity with the given system ID from the database and then do the resolution, see below for an illustration:
private static class MyEntityResolver
{
public InputSource resolveEntity(String publicId, String systemId)
throws SAXException, IOException
{
// At this point, systemId is always absolutized to the current working directory,
// even though the XML document specified it as relative.
// E.g. "file:///H:/mydoc.dtd" instead of just "mydoc.dtd"
// Why??? How can I prevent this???
SgmlEntity entity = findEntityFromDatabase(systemId);
InputSource is = new InputSource(new ByteArrayInputStream(entity.getContents()));
is.setPublicId(publicId);
is.setSystemId(systemId);
return is;
}
}
I tried both using DOM (DocumentBuilder) and SAX (XMLReader), set the entity resolver to MyEntityResolver (i.e. setEntityResolver(new MyEntityResolver())
), but systemId
in MyEntityResolver#resolveEntity(String publicId, String systemId)
is always being absolutized to the current working directory.
I also tried calling setFeature("http://xml.org/sax/features/resolve-dtd-uris", false);
, but that didn't help anything.
So how can I achieve what I wanted?
Thanks!
Apparently, there is another interface called EntityResolver2 which is the extension of the old EntityResolver. (Talk about confusing names!)
Anyway, I found that EntityResolver2
achieved what I wanted, that is, it does not make any changes to the systemId
, so it will always exactly be what was specified in the XML document.
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