做一個遞歸遍歷XML的例子,為更為復雜的解析工作做基礎。
目標:遍歷所有的元素節點,並且取出來其中的值,結果打印到控制台。
源代碼如下:
本程序依賴DOM4j包。
import org.dom4j.Document; import org.dom4j.DocumentHelper; import org.dom4j.DocumentException; import org.dom4j.Element; import java.util.*; /** * Created by IntelliJ IDEA.<br> * <b>User</b>: leizhimin<br> * <b>Date</b>: 2008-4-14 14:02:12<br> * <b>Note</b>: Java遞歸遍歷XML所有元素 */ public class XmlTest { // private static Map<String, String> xmlmap = new HashMap<String, String>(); //存儲xml元素信息的容器 private static List<Leaf> elemList = new ArrayList<Leaf>(); //要測試的xml對象 private static String srcXml = "<?xml version=\"1.0\" encoding=\"GBK\"?>\n" + "<doc>\n" + " <person>\n" + " <name>某人</name>\n" + " <adds> \n" + " <add ID=\"10002\">\n" + " <BS>10002</BS>\n" + " <note>西安市太白路</note>\n" + " </add>\n" + " <add ID=\"\">\n" + " <BS>10002</BS>\n" + " <note>空ID節點啊</note>\n" + " </add>\n" + " <add>\n" + " <BS>10002</BS>\n" + " <note>空ID節點啊</note>\n" + " </add>\n" + "\t\t\t<add ID=\"10001\">\n" + "\t\t\t\t<BS xmlns=\"10001\"/>\n" + " <note>西安市太白路2</note>\n" + " </add>\n" + "\t\t</adds>\n" + " </person>\n" + " <other>\n" + " <name ID=\"HEHE\">ASDF</name>\n" + " </other>\n" + "</doc>"; public static void main(String args[]) throws DocumentException { XmlTest test = new XmlTest(); Element root = test.getRootElement(); test.getElementList(root); String x = test.getListString(elemList); System.out.println("-----------原xml內容------------"); System.out.println(srcXml); System.out.println("-----------解析結果------------"); System.out.println(x); } /** * 獲取根元素 * * @return * @throws DocumentException */ public Element getRootElement() throws DocumentException { Document srcdoc = DocumentHelper.parseText(srcXml); Element elem = srcdoc.getRootElement(); return elem; } /** * 遞歸遍歷方法 * * @param element */ public void getElementList(Element element) { List elements = element.elements(); if (elements.size() == 0) { //沒有子元素 String xpath = element.getPath(); String value = element.getTextTrim(); elemList.add(new Leaf(xpath, value)); } else { //有子元素 for (Iterator it = elements.iterator(); it.hasNext();) { Element elem = (Element) it.next(); //遞歸遍歷 getElementList(elem); } } } public String getListString(List<Leaf> elemList) { StringBuffer sb = new StringBuffer(); for (Iterator<Leaf> it = elemList.iterator(); it.hasNext();) { Leaf leaf = it.next(); sb.append(leaf.getXpath()).append(" = ").append(leaf.getValue()).append("\n"); } return sb.toString(); } } /** * xml節點數據結構 */ class Leaf { private String xpath; // private String value; public Leaf(String xpath, String value) { this.xpath = xpath; this.value = value; } public String getXpath() { return xpath; } public void setXpath(String xpath) { this.xpath = xpath; } public String getValue() { return value; } public void setValue(String value) { this.value = value; } }
運行結果:
-----------原xml內容------------
<?xml version="1.0" encoding="GBK"?>
<doc>
<person>
<name>某人</name>
<adds>
<add ID="10002">
<BS>10002</BS>
<note>西安市太白路</note>
</add>
<add ID="">
<BS>10002</BS>
<note>空ID節點啊</note>
</add>
<add>
<BS>10002</BS>
<note>空ID節點啊</note>
</add>
<add ID="10001">
<BS xmlns="10001"/>
<note>西安市太白路2</note>
</add>
</adds>
</person>
<other>
<name ID="HEHE">ASDF</name>
</other>
</doc>
-----------解析結果------------
/doc/person/name = 某人
/doc/person/adds/add/BS = 10002
/doc/person/adds/add/note = 西安市太白路
/doc/person/adds/add/BS = 10002
/doc/person/adds/add/note = 空ID節點啊
/doc/person/adds/add/BS = 10002
/doc/person/adds/add/note = 空ID節點啊
/doc/person/adds/add/*[name()='BS'] =
/doc/person/adds/add/note = 西安市太白路2
/doc/other/name = ASDF
Process finished with exit code 0
可以發現,有很多xpath相同的值域。