如何使用Java和Stax从Xml中删除元素及其子元素

Question

我有一个包含如下数据的大文件

<releases>
   <release>
   ......
      <companies>
         <company>
         </company>
      </companies>
   </release>
   <release>
   ......
</releases>

我想产生和输出文件相同的输入文件，但所有的公司元素和他们的子删除。我试着使用Stax，我认为它会遍历元素，然后如果我得到匹配，我就可以不写那个元素，section就会被删除。例如，如果我扔掉一个元素，它会导致其中的元素和被删除，但它似乎只是删除了元素本身，没有其他，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);
            } 
        }

Answer 1

我想我现在有了，Stax逐个元素处理元素，所以我需要标记何时找到开始元素，设置一个变量来指示所有后续数据应该被忽略，直到到达结束元素。

代码例子:

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);
            }
        }
    }
}