Question

所以我想这样做。添加新的根元素并将旧元素包装在其中。

将此作为开始条件

// this part uses SAXParser
org.w3c.com.Document = xmlSrc.parse(is); // *is* is InputStream

最初的条件并不是真的可以谈判，但我也愿意听取那里的意见

所以给出了这个xml文件

<?xml version="1.0" encoding="UTF-8"?>
<root1>
   <elem>...</elem>
</root1>

我需要在Java中生成一个InputStream，其中包含此格式的

的xml文件

<?xml version="1.0" encoding="UTF-8"?>
<newroot>
   <root1>
       <elem>...</elem>
   </root1>
</newroot>

存储在某些InputStream isNewXML

中

我很好奇这是做什么的最好方法。我是Java新手，java有十亿种方法可以做同样的事情，所以在黑暗中这将是最好的

Answer 1

Document也是Node - 根元素是文档的第一个也是唯一的子元素，您可以像处理任何其他文档一样操纵Document的子节点：

Document doc = parser.parse(new File("build.xml"));

Element newRoot = doc.createElement("newroot");
newRoot.appendChild(doc.getFirstChild());
doc.appendChild(newRoot);

// output to wrapped.xml
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.transform(new DOMSource(doc), new StreamResult(new File("wrapped.xml")));

如果您需要处理DOM解析开销很大的文件，那么使用StAX也很容易。

Answer 2

使用您的示例输入，这将创建请求的输出。理想情况下，您可以正确处理异常并关闭输入流，输出流和编写器：

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

public class XmlTest
{

    public static void main(String[] args) throws Exception
    {
        InputStream is = new FileInputStream("test.xml");
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();

        Document oldDoc = builder.parse(is);
        Node oldRoot = oldDoc.getDocumentElement();
        Document newDoc = builder.newDocument();
        Element newRoot = newDoc.createElement("newroot");
        newDoc.appendChild(newRoot);
        newRoot.appendChild(newDoc.importNode(oldRoot, true));

        ByteArrayOutputStream out = new ByteArrayOutputStream();
        DOMSource domSource = new DOMSource(newDoc);
        Writer writer = new OutputStreamWriter(out);
        StreamResult result = new StreamResult(writer);
        TransformerFactory tf = TransformerFactory.newInstance();
        Transformer transformer = tf.newTransformer();
        transformer.transform(domSource, result);
        writer.flush();

        InputStream isNewXML = new ByteArrayInputStream(out.toByteArray());

    }

}

Answer 3

这可能会有所帮助

import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class WriteXMLFile {

    public static void main(String argv[]) {

      try {

        DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder docBuilder = docFactory.newDocumentBuilder();

        // root elements
        Document doc = docBuilder.newDocument();
        Element rootElement = doc.createElement("root");
        doc.appendChild(rootElement);



        // write the content into xml file
        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        DOMSource source = new DOMSource(doc);
        StreamResult result = new StreamResult(new File("build.xml"));

        // Output to console for testing
        // StreamResult result = new StreamResult(System.out);

        transformer.transform(source, result);

        System.out.println("File saved!");

      } catch (ParserConfigurationException pce) {
        pce.printStackTrace();
      } catch (TransformerException tfe) {
        tfe.printStackTrace();
      }
    }
}

在存储在org.w3c.dom.Document中的给定XML文件的根元素周围添加元素

3 个答案: