xml文檔的解析有兩種方式: 一是DOM解析,一是SAX
我們用的是dom4j的解析包,其對DOM和SAX都支持解析.
java自帶以下是DOM解析.
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();		factory.setValidating(false);		DocumentBuilder builder = factory.newDocumentBuilder();		Document doc = builder.parse("src/students.xml");
      DOM4J獲取Document對象: 		
		SAXReader reader = new SAXReader();		Document doc = reader.read("src/students.xml");
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java自帶SAX的解析:
SAXParserFactory factory =SAXParserFactory.newInstance();
       SAXParser parser = factory.newSAXParser();
       parser.parse("src/students.xml",new DefaultHandler()); DefaultHandler-->需要創建實現這個DefaultHandler接口的實現類
Dom4j通過SAX獲得document對象:
SAXReader reader = new SAXReader();
            Document doc = reader.read(input); input------>讀取xml文件的內容
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回顯或寫入xml內容
OutputFormat format = OutputFormat.createPRettyPrint();        //設置輸出編碼        format.setEncoding("UTF-8");        //創建需要寫入的File對象        File file = new File("D:" + File.separator + "books.xml");        //生成XMLWriter對象，構造函數中的參數為需要輸出的文件流和格式        XMLWriter writer = new XMLWriter(new FileOutputStream(file), format);        //開始寫入，write方法中包含上面創建的Document對象        writer.write(doc);
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另外, dom4j支持xpath的(查詢)操作.
dom4j的下載地址為: https://sourceforge.net/projects/dom4j/files/dom4j/