Java解析XML（二）、DOM

短命女 2022-06-15 00:42 139阅读 0赞

**XML资源文件请见**[**http://blog.csdn.net/xyang81/article/details/7247169**][http_blog.csdn.net_xyang81_article_details_7247169]

package xml;
    
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStreamWriter;
    import java.io.Writer;
    import java.util.ArrayList;
    import java.util.List;
    
    import javax.xml.parsers.DocumentBuilder;
    import javax.xml.parsers.DocumentBuilderFactory;
    import javax.xml.transform.OutputKeys;
    import javax.xml.transform.Result;
    import javax.xml.transform.Source;
    import javax.xml.transform.Transformer;
    import javax.xml.transform.TransformerConfigurationException;
    import javax.xml.transform.TransformerException;
    import javax.xml.transform.TransformerFactory;
    import javax.xml.transform.dom.DOMSource;
    import javax.xml.transform.stream.StreamResult;
    
    import model.Book;
    
    import org.w3c.dom.Document;
    import org.w3c.dom.Element;
    import org.w3c.dom.Node;
    import org.w3c.dom.NodeList;
    
    import util.DateUtils;
    
    /**
     * 使用DOM读写XML
     * @author 杨信
     *
     */
    public class DomHelper {
    	
    	private static DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    	
    	/**
    	 * 使用DOM解析XML
    	 * @param is XML文件输入流
    	 * @return 解析后的数据
    	 */
    	public static List<Book> domReader(InputStream is) {
    		List<Book> books = null;
    		try {
    			DocumentBuilder db = dbf.newDocumentBuilder();
    			Document document = db.parse(is);
    			Element rootElement = document.getDocumentElement();
    			NodeList nodes = rootElement.getElementsByTagName("book");
    			if (nodes != null && nodes.getLength() > 0) {
    				books = new ArrayList<Book>();
    				for(int i = 0; i < nodes.getLength(); i++) {
    					/*//获得节点方式1
    					Node node = nodes.item(i);
    					book.setIsbn(node.getAttributes().item(0).getNodeValue());	//获得book节点ISBN属性的值
    					//获得book节点下的所有子节点
    					NodeList bookChildList = node.getChildNodes();*/
    					//获得节点方式2
    					Book book = new Book();
    					Element bookElement = (Element) nodes.item(i);
    					book.setIsbn(bookElement.getAttribute("isbn"));	//获得book节点ISBN属性的值
    					NodeList bookChildList = bookElement.getChildNodes();
    					for(int j = 0; j < bookChildList.getLength(); j++) {
    						Node childNode = bookChildList.item(j);
    						if (childNode.getNodeType() == Node.ELEMENT_NODE) {	//判断当前节点类型,是否为一个元素节点.(节点类型分:Element和Text节点.)
    							String nodeName = childNode.getNodeName();
    							String nodeValue = childNode.getTextContent();
    							if ("name".equals(nodeName)) {
    								book.setName(nodeValue);
    							} else if ("author".equals(nodeName)) {
    								book.setAuthor(nodeValue);
    							} else if ("publishing".equals(nodeName)) {
    								book.setPublishing(nodeValue);
    							} else if ("pubdate".equals(nodeName)) {
    								book.setPubdate(DateUtils.string2Date("yyyy-mm-dd", nodeValue));
    							} else if ("price".equals(nodeName)) {
    								book.setPrice(Double.parseDouble(nodeValue));
    							}
    						}
    					}
    					books.add(book);
    				}
    			}
    		} catch (Exception e) {
    			e.printStackTrace();
    		} finally {
    			try {
    				is.close();
    			} catch (IOException e) {
    				e.printStackTrace();
    			}
    		}
    		return books;
    	}
    
    	/**
    	 * 使用dom写xml文件
    	 * @param books 数据
    	 * @param outfile xml文件保存位置
    	 */
    	public static void domWriter(List<Book> books,File outfile) {
    		Document doc = null;
    		try {
    			DocumentBuilder db = dbf.newDocumentBuilder();
    			doc = db.newDocument();
    			Element booksElement = doc.createElement("books");
    			for (Book book : books) {
    				//创建一本图书
    				Element bookElement = doc.createElement("book");
    				//设置图片的编号
    				bookElement.setAttribute("isbn", book.getIsbn());
    				//书名
    				Element nameElement = doc.createElement("name");
    				nameElement.setTextContent(book.getName());
    				bookElement.appendChild(nameElement);
    				//作者
    				Element authorElement = doc.createElement("author");
    				authorElement.setTextContent(book.getAuthor());
    				bookElement.appendChild(authorElement);
    				//出版社
    				Element publishingElement = doc.createElement("publishing");
    				publishingElement.setTextContent(book.getPublishing());
    				bookElement.appendChild(publishingElement);
    				//出版日期
    				Element pubdateElement = doc.createElement("pubdate");
    				pubdateElement.setTextContent(DateUtils.date2String("yyyy-mm-dd", book.getPubdate()));
    				bookElement.appendChild(pubdateElement);
    				//价格
    				Element priceElement = doc.createElement("price");
    				priceElement.setTextContent(String.valueOf(book.getPrice()));
    				bookElement.appendChild(priceElement);
    				//将每本书添加到根节点中
    				booksElement.appendChild(bookElement);
    			}
    			doc.appendChild(booksElement);
    			//将数据生成xml文件
    			FileOutputStream fos = new FileOutputStream(outfile);
    			OutputStreamWriter outwriter = new OutputStreamWriter(fos);
    			callWriteXmlFile(doc, outwriter, "gb2312");
    			outwriter.close();
    			fos.close();
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    	
    	/**
    	 * 定入xml文件
    	 * @param doc xml文档对象
    	 * @param w 写xml文件的字符流对象
    	 * @param encoding xml编码
    	 */
    	public static void callWriteXmlFile(Document doc, Writer w, String encoding) {
    		try {
    			Source source = new DOMSource(doc);
    			Result result = new StreamResult(w);
    			Transformer xformer = TransformerFactory.newInstance().newTransformer();
    			xformer.setOutputProperty(OutputKeys.ENCODING, encoding);
    			xformer.transform(source, result);
    		} catch (TransformerConfigurationException e) {
    			e.printStackTrace();
    		} catch (TransformerException e) {
    			e.printStackTrace();
    		}
    	}
    
    }

[http_blog.csdn.net_xyang81_article_details_7247169]: http://blog.csdn.net/xyang81/article/details/7247169