[英]How do I remove elements and their children from Xml using Java and Stax
我有一个大文件,包含这样的数据
<releases>
<release>
......
<companies>
<company>
</company>
</companies>
</release>
<release>
......
</releases>
我想产生和输出文件的方式与输入文件相同,但要删除所有公司元素及其子元素。我正在尝试使用Stax,我认为它会遍历所有元素,然后如果匹配成功,我可以只是不写那个元素,该部分将被删除。 即,如果我丢弃了导致其中的元素并被删除的元素,但似乎它只是删除了元素本身而没有其他任何东西,对吗?
即
<releases>
<release>
......
</release>
<release>
......
</releases>
这是我目前拥有的代码:
XMLInputFactory inputFactory = XMLInputFactory.newInstance();
XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
InputStream in = new FileInputStream(source);
XMLEventReader reader = inputFactory.createXMLEventReader(in);
OutputStream out = new FileOutputStream(target);
XMLEventWriter writer = outputFactory.createXMLEventWriter(out);
XMLEvent event;
while(reader.hasNext()){
event = reader.nextEvent();
writer.add(event);
if(event.getEventType() == XMLStreamConstants.START_ELEMENT)
{
if(event.asStartElement().getName().toString().equalsIgnoreCase("companies"))
{
System.out.println("Deleting:"+event);
continue;
}
else
{
writer.add(event);
}
}
else
{
writer.add(event);
}
}
我想我已经有了,Stax逐个元素地处理,因此我需要标记何时找到起始元素,设置一个变量以指示所有后续数据都应被忽略,直到到达结束元素为止。
代码示例:
import javax.xml.stream.*;
import javax.xml.stream.events.XMLEvent;
import java.io.*;
public class FixDb
{
public static void main(String[] args) throws Exception
{
File source = new File(args[0]);
if(!source.exists())
{
System.out.println("File:"+source+ " does not exist");
}
File target = new File(source+".new");
XMLInputFactory inputFactory = XMLInputFactory.newInstance();
XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
InputStream in = new FileInputStream(source);
XMLEventReader reader = inputFactory.createXMLEventReader(in);
OutputStream out = new FileOutputStream(target);
XMLEventWriter writer = outputFactory.createXMLEventWriter(out);
XMLEvent event;
boolean deleteSection = false;
while(reader.hasNext())
{
event = reader.nextEvent();
if(event.getEventType() == XMLStreamConstants.START_ELEMENT && event.asStartElement().getName().toString().equalsIgnoreCase("companies"))
{
deleteSection=true;
continue;
}
else if(event.getEventType() == XMLStreamConstants.END_ELEMENT && (event.asEndElement().getName().toString().equalsIgnoreCase("companies")))
{
deleteSection=false;
continue;
}
else if(deleteSection)
{
continue;
}
else
{
writer.add(event);
}
}
}
}
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