Java 中的 XML 节点到字符串
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XML Node to String in Java
提问by Kevin
I came across this piece of Java function to convert an XML node to a Java String representation:
我遇到了这段将 XML 节点转换为 Java 字符串表示的 Java 函数：
private String nodeToString(Node node) {
StringWriter sw = new StringWriter();
try {
Transformer t = TransformerFactory.newInstance().newTransformer();
t.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
t.setOutputProperty(OutputKeys.INDENT, "yes");
t.transform(new DOMSource(node), new StreamResult(sw));
} catch (TransformerException te) {
System.out.println("nodeToString Transformer Exception");
}
return sw.toString();
}
It looks straightforward in that it wants the output string doesn't have any XML declaration and it must contain indentation.
它看起来很简单，因为它希望输出字符串没有任何 XML 声明并且它必须包含缩进。
But I wonder how the actual output should be, suppose I have an XML node:
但我想知道实际输出应该如何，假设我有一个 XML 节点：
<p><media type="audio" id="au008093" rights="wbowned">
<title>Bee buzz</title>
</media>Most other kinds of bees live alone instead of in a colony. These bees make
tunnels in wood or in the ground. The queen makes her own nest.</p>
Could I assume the resulting String after applying the above transformation is:
我可以假设应用上述转换后的结果字符串是：
"media type="audio" id="au008093" rights="wbowned" title Bee buzz title /media"
I want to test it myself, but I have no idea on how to represent this XML node in the way this function actually wants.
我想自己测试它，但我不知道如何以这个函数实际想要的方式来表示这个 XML 节点。
I am bit confused, and thanks in advance for the generous help.
我有点困惑，在此先感谢您的慷慨帮助。
采纳答案by Cratylus
You have an XML respesentation in a DOM tree.
For example you have opened an XML file and you have passed it in the DOM parser.
As a result a DOM tree in memory with your XML is created.
Now you can only access the XML info via traversal of the DOM tree.
If you need though, a String representation of the XML info of the DOM tree you use a transformation.
This happens since it is not possible to get the String representation directly from a DOM tree.
So if for example as Node nodeyou pass in nodeToStringis the root element of the XML doc then the result is a String containing the original XML data.
The tags will still be there. I.e. you will have a valid XML representation. Only this time will be in a String variable.
您在 DOM 树中有一个 XML respesentation。
例如，您打开了一个 XML 文件，并在 DOM 解析器中传递了它。
结果是在内存中创建了一个带有 XML 的 DOM 树。
现在您只能通过遍历 DOM 树来访问 XML 信息。
如果需要，您可以使用转换的 DOM 树的 XML 信息的字符串表示。
发生这种情况是因为无法直接从 DOM 树获取 String 表示。
因此，例如，如果Node node您传入的nodeToString是 XML 文档的根元素，则结果是一个包含原始 XML 数据的字符串。
标签仍然存在。即您将有一个有效的 XML 表示。只有这一次将在 String 变量中。
For example:
例如：
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder parser = factory.newDocumentBuilder();
Document xmlDoc = parser.parse(file);//file has the xml
String xml = nodeToString(xmlDoc.getDocumentElement());//pass in the root
//xml has the xml info. E.g no xml declaration. Add it
xml = "<?xml version=\"1.0\" encoding=\"UTF-8\" ?> + xml;//bad to append this way...
System.out.println("XML is:"+xml);
DISCLAIMER:Did not even attempt to compile code. Hopefully you understand what you have to do
免责声明：甚至没有尝试编译代码。希望你明白你必须做什么
回答by Jiri Patera
All important has already been said. I tried to compile the following code.
重要的都说了。我试图编译以下代码。
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.StringWriter;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
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.Document;
import org.w3c.dom.Node;
public class Test {
public static void main(String[] args) throws Exception {
String s =
"<p>" +
" <media type=\"audio\" id=\"au008093\" rights=\"wbowned\">" +
" <title>Bee buzz</title>" +
" " +
" Most other kinds of bees live alone instead of in a colony." +
" These bees make tunnels in wood or in the ground." +
" The queen makes her own nest." +
"</p>";
InputStream is = new ByteArrayInputStream(s.getBytes());
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document d = db.parse(is);
Node rootElement = d.getDocumentElement();
System.out.println(nodeToString(rootElement));
}
private static String nodeToString(Node node) {
StringWriter sw = new StringWriter();
try {
Transformer t = TransformerFactory.newInstance().newTransformer();
t.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
t.setOutputProperty(OutputKeys.INDENT, "yes");
t.transform(new DOMSource(node), new StreamResult(sw));
} catch (TransformerException te) {
System.out.println("nodeToString Transformer Exception");
}
return sw.toString();
}
}
And it produced the following output:
它产生了以下输出：
<p> <media id="au008093" rights="wbowned" type="audio"> <title>Bee buzz</title> </media> Most other kinds of bees live alone instead of in a colony. These bees make tunnels in wood or in the ground. The queen makes her own nest.</p>
You can further tweak it by yourself. Good luck!
您可以自己进一步调整它。祝你好运！
