DOM方式进行的XML文件、Document、String之间的相互转换

XML文件test.xml：

<?xml version="1.0" encoding="UTF-8"?><books><book><name>哈里波特</name><price>10</price><memo>这是一本很好看的书。</memo></book></books>

 

java代码：

import java.io.*;
import java.net.URI;

import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.xml.sax.InputSource;

import com.sun.org.apache.xml.internal.serialize.*;

/**
 * DOM方式操作XML
 * 
 * @author Watson Xu
 * @date 2011-5-3 上午09:49:27
 */
public class OperateXMLByDOM {
	/**
	 * 将给定文件的内容或者给定 URI 的内容解析为一个 XML 文档，并且返回一个新的 DOM Document 对象
	 * 
	 * @param filePath 文件所在路径
	 * @return DOM的Document对象
	 * @throws Exception
	 */
	public static Document xml2Doc(String filePath) {
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		DocumentBuilder builder = null;
		FileInputStream inputStream = null;
		Document doc = null;
		try {
			builder = factory.newDocumentBuilder();

			/* 通过文件方式读取,注意文件保存的编码和文件的声明编码要一致(默认文件声明是UTF-8) */
			File file = new File(filePath);
			doc = builder.parse(file);

			/* 通过一个URL方式读取 */
			URI uri = new URI(filePath);//filePath="http://java.sun.com/index.html"
			doc = builder.parse(uri.toString());

			/* 通过java IO 流的读取 */
			inputStream = new FileInputStream(filePath);
			doc = builder.parse(inputStream);
			return doc;
		} catch (Exception e) {
			return null;
		} finally {
			if (inputStream != null) {
				try {
					inputStream.close();
				} catch (IOException e) {
					return null;
				}
			}
		}
	}

	/**
	 * Document 转换为 String 并且进行了格式化缩进
	 * 
	 * @param doc XML的Document对象
	 * @return String
	 */
	public static String doc2FormatString(Document doc) {		
		StringWriter stringWriter = null;
		try {
			stringWriter = new StringWriter();
			if(doc != null){
				OutputFormat format = new OutputFormat(doc,"UTF-8",true);
				//format.setIndenting(true);//设置是否缩进，默认为true
				//format.setIndent(4);//设置缩进字符数
				//format.setPreserveSpace(false);//设置是否保持原来的格式,默认为 false
				//format.setLineWidth(500);//设置行宽度
				XMLSerializer serializer = new XMLSerializer(stringWriter,format);
				serializer.asDOMSerializer();
				serializer.serialize(doc);
				return stringWriter.toString();
			} else {
				return null;
			}
        } catch (Exception e) {
        	return null;
        } finally {
        	if(stringWriter != null){
	        	try {
					stringWriter.close();
				} catch (IOException e) {
					return null;
				}
        	}
        }
	}
	
	/**
	 * Document 转换为 String
	 * 
	 * @param doc XML的Document对象
	 * @return String
	 */
	public static String doc2String(Document doc){
		try {
			Source source = new DOMSource(doc);
	        StringWriter stringWriter = new StringWriter();
	        Result result = new StreamResult(stringWriter);
	        TransformerFactory factory = TransformerFactory.newInstance();
	        Transformer transformer = factory.newTransformer();
	        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
	        transformer.transform(source, result);
	        return stringWriter.getBuffer().toString();
		} catch (Exception e) {
			return null;
		}
	}

	/**
	 * String 转换为 Document 对象
	 * 
	 * @param xml 字符串
	 * @return Document 对象
	 */
	public static Document string2Doc(String xml) {
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		DocumentBuilder builder = null;
		Document doc = null;
		InputSource source = null;
		StringReader reader = null;
		try {
			builder = factory.newDocumentBuilder();
			reader = new StringReader(xml);
			source = new InputSource(reader);//使用字符流创建新的输入源
			doc = builder.parse(source);
			return doc;
		} catch (Exception e) {
			return null;
		} finally {
			if(reader != null){
				reader.close();
			}
		}
	}

	/**
	 * Document 保存为 XML 文件
	 * 
	 * @param doc Document对象
	 * @param path 文件路径
	 */
	public static void doc2XML(Document doc, String path) {
		try {
			Source source = new DOMSource(doc);
	        Result result = new StreamResult(new File(path));
	        Transformer transformer = TransformerFactory.newInstance().newTransformer();
	        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
	        transformer.transform(source, result);
		} catch (Exception e) {
			return;
		}
	}

	public static void main(String[] args) {
		Document doc = xml2Doc("test.xml");
		System.out.println(doc);
		System.out.println(doc2String(doc));
		System.out.println(doc2FormatString(doc));
		doc = string2Doc(doc2FormatString(doc));
		doc2XML(doc, "1.xml");
	}
}

 

 

输出的XML文件1.xml：

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<books>
    <book>
        <name>哈里波特</name>
        <price>10</price>
        <memo>这是一本很好看的书。</memo>
    </book>
</books>