在Java中，XML用org.w3c.dom.Document对象表示。 在本XML教程中，我们将学习-将XML string to XML转换string to XML文档

将XML文件内容转换为XML文档

1) Convert String to XML Document

要将XML字符串转换为XML Dom ，我们需要以下类：

javax.xml.parsers.DocumentBuilder ：定义API，以从来自各种输入源的XML内容中获取XML DOM Document实例。 这些输入源是InputStreams，Files，URL和SAX InputSources。

javax.xml.parsers.DocumentBuilderFactory ：定义一个工厂API，使应用程序能够获取解析器( DocumentBuilder )，该解析器从XML内容生成DOM对象树。

org.w3c.dom.Document ：它表示整个XML DOM。 从概念上讲，它是文档树的根，并通过工厂方法提供对文档数据的访问，直到树的下层。

java.io.StringReader ：从字符串内容创建流。 DocumentBuilder使用此流读取XML内容进行解析。package com.howtodoinjava.demo;

import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;

import org.xml.sax.InputSource;

public class StringtoXMLExample

{

public static void main(String[] args)

{

final String xmlStr = "" +

"" +

" Lokesh Gupta" +

"

Author" +

"" +

"" +

" Brian Lara" +

"

Cricketer" +

"" +

"";

//Use method to convert XML string content to XML Document object

Document doc = convertStringToXMLDocument( xmlStr );

//Verify XML document is build correctly

System.out.println(doc.getFirstChild().getNodeName());

}

private static Document convertStringToXMLDocument(String xmlString)

{

//Parser that produces DOM object trees from XML content

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

//API to obtain DOM Document instance

DocumentBuilder builder = null;

try

{

//Create DocumentBuilder with default configuration

builder = factory.newDocumentBuilder();

//Parse the content to Document object

Document doc = builder.parse(new InputSource(new StringReader(xmlString)));

return doc;

}

catch (Exception e)

{

e.printStackTrace();

}

return null;

}

}

//Output:

employees

2) Convert XML file to XML Document

要从XML文件获取XML dom ，而不是将XML字符串传递给DocumentBuilder ，而是传递文件路径以使解析器直接读取文件内容。

我们有一个具有XML内容的employees.xml文件，我们将阅读以获取XML文档。

Lokesh Gupta

Author

Brian Lara

Cricketer

package com.howtodoinjava.demo;

import java.io.File;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;

public class StringtoXMLExample

{

public static void main(String[] args)

{

final String xmlFilePath = "employees.xml";

//Use method to convert XML string content to XML Document object

Document doc = convertXMLFileToXMLDocument( xmlFilePath );

//Verify XML document is build correctly

System.out.println(doc.getFirstChild().getNodeName());

}

private static Document convertXMLFileToXMLDocument(String filePath)

{

//Parser that produces DOM object trees from XML content

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

//API to obtain DOM Document instance

DocumentBuilder builder = null;

try

{

//Create DocumentBuilder with default configuration

builder = factory.newDocumentBuilder();

//Parse the content to Document object

Document doc = builder.parse(new File(filePath));

return doc;

}

catch (Exception e)

{

e.printStackTrace();

}

return null;

}

}

//Output:

employees