Dom4j讀寫XML簡介

要使用dom4j讀寫XML文檔,需要先下載dom4j包,dom4j官方網站在 http://www.dom4j.org/
目前最新dom4j包下載地址:http://nchc.dl.sourceforge.net/sourceforge/dom4j/dom4j-1.6.1.zip 解開後有兩個包,僅操作XML文檔的話把dom4j-1.6.1.jar加入工程就可以了,如果需要使用XPath的話還需要加入包jaxen-1.1-beta-7.jar.

以下是相關操作:

一.Document對象相關

1.讀取XML文件,獲得document對象.

             SAXReader reader = new SAXReader();
             Document   document = reader.read( new File( " input.xml " ));

2.解析XML形式的文本,得到document對象.

             String text = " <members></members> " ;
             Document document = DocumentHelper.parseText(text);

3.主動創建document對象.

             Document document = DocumentHelper.createDocument();
             Element root = document.addElement( " members " ); // 創建根節點

二.節點相關

1.獲取文檔的根節點.

Element rootElm = document.getRootElement();

2.取得某節點的單個子節點.

Element memberElm = root.element( " member " ); // "member"是節點名

3.取得節點的文字

String text = memberElm.getText();

也可以用:

String text = root.elementText( " name " );

這個是取得根節點下的name字節點的文字.

4.取得某節點下名爲"member"的所有字節點並進行遍歷.

List nodes = rootElm.elements( " member " );

for (Iterator it = nodes.iterator(); it.hasNext();) {
    Element elm = (Element) it.next();
    // do something
}

5.對某節點下的所有子節點進行遍歷.

             for (Iterator it = root.elementIterator();it.hasNext();) {
                 Element element = (Element) it.next();
                 // do something
             }

6.在某節點下添加子節點.

Element ageElm = newMemberElm.addElement( " age " );

7.設置節點文字.

ageElm.setText( " 29 " );

8.刪除某節點.

parentElm.remove(childElm); // childElm是待刪除的節點,parentElm是其父節點

9.添加一個CDATA節點.

         Element contentElm = infoElm.addElement( " content " );
         contentElm.addCDATA(diary.getContent());

三.屬性相關.
1.取得某節點下的某屬性

             Element root = document.getRootElement();    
             Attribute attribute = root.attribute( " size " ); // 屬性名name

2.取得屬性的文字

             String text = attribute.getText();

也可以用:

String text2 = root.element( " name " ).attributeValue( " firstname " );

這個是取得根節點下name字節點的屬性firstname的值.

3.遍歷某節點的所有屬性

             Element root = document.getRootElement();    
             for (Iterator it = root.attributeIterator();it.hasNext();) {
                 Attribute attribute = (Attribute) it.next();
                 String text = attribute.getText();
                 System.out.println(text);
             }

4.設置某節點的屬性和文字.

newMemberElm.addAttribute( " name " , " sitinspring " );

5.設置屬性的文字

             Attribute attribute = root.attribute( " name " );
             attribute.setText( " sitinspring " );

6.刪除某屬性

             Attribute attribute = root.attribute( " size " ); // 屬性名name
             root.remove(attribute);

四.將文檔寫入XML文件.
1.文檔中全爲英文,不設置編碼,直接寫入的形式.

XMLWriter writer = new XMLWriter( new FileWriter( " output.xml " ));
writer.write(document);
writer.close();

2.文檔中含有中文,設置編碼格式寫入的形式.

             OutputFormat format = OutputFormat.createPrettyPrint();
             format.setEncoding( " GBK " );     // 指定XML編碼        
             XMLWriter writer = new XMLWriter( new FileWriter( " output.xml " ),format);
            
             writer.write(document);
             writer.close();

五.字符串與XML的轉換
1.將字符串轉化爲XML

String text = " <members> <member>sitinspring</member> </members> " ;
Document document = DocumentHelper.parseText(text);

2.將文檔或節點的XML轉化爲字符串.

             SAXReader reader = new SAXReader();
             Document   document = reader.read( new File( " input.xml " ));            
             Element root = document.getRootElement();                
             String docXmlText = document.asXML();
             String rootXmlText = root.asXML();
             Element memberElm = root.element( " member " );
             String memberXmlText = memberElm.asXML();