jdom+xpath 的问题

Question

我用 jdom + xPath 解析下面的 sample.xml 文件:
<?xml version="1.0" encoding="UTF-8"?>     
<HD>     
 <disk name="C">     
  <capacity>8G</capacity>     
  <directories>200</directories>     
  <files>1580</files>     
 </disk>     
 <disk name="D">       
  <capacity>10G</capacity>     
  <directories>500</directories>     
  <files>3000</files>       
 </disk>     
 <disk name="E">       
  <capacity>20G</capacity>     
  <directories>800</directories>     
  <files>10000</files>       
 </disk>  
</HD>
java代码：
public class Test {   
    private Document doc;   
  
    public Test(String file) throws Exception {   
        SAXBuilder sb = new SAXBuilder();   
        doc = sb.build(file);   
    }   
  
    private Element getRootElement() {   
        return doc.getRootElement();   
    }   
  
    public String getValue(Element element, String xPath) throws Exception {   
        return ((Text) XPath.selectSingleNode(element, xPath)).getTextNormalize();   
    }   
  
    public List<Element> getList(String xPath) throws Exception {   
        List<Element> result = new ArrayList<Element>();   
  
        List list = XPath.selectNodes(getRootElement(), xPath);   
        for(Object o : list) result.add((Element) o);   
  
        return result;   
    }   
  
    public static void main(String[] args) throws Exception {   
        String file = "sample.xml";   
        Test test = new Test(file);   
  
        List<Element> list = test.getList("/HD/disk");   
        for(Element e : list) {   
            System.out.println("name : " + e.getAttributeValue("name"));   
            System.out.println("capacity : " + test.getValue(e, "capacity/text()"));   
            System.out.println("disk C capacity : " + test.getValue(e, "//disk[@name='C']/capacity/text()"));   
            System.out.println("--------------");   
        }   
    }   
}
输出结果：name : C   
capacity : 8G   
disk C capacity : 8G   
--------------   
name : D   
capacity : 10G   
disk C capacity : 8G   
--------------   
name : E   
capacity : 20G   
disk C capacity : 8G   
--------------  
为什么下面这一行没有问题呢？System.out.println("disk C capacity : " + test.getValue(e, "//disk[@name='C']/capacity/text()")); 为什么在 name 为 D 和 E 时还能够访问到 disk C 的属性值呢？？？ 

Answer 1

给你一个例子吧！
前几天刚用过这个：<?xml version="1.0" encoding="UTF-8"?>
<dataSource>
<hostAddress>192.168.134.64</hostAddress>
<databaseName>dbname</databaseName>
<userName>sa</userName>
<password>123</password>
</dataSource>
解析代码：public static HashMap getDataSource(String dataSourcePath){
// String dataSourcePath="c:/param/dataSource_RecordDB.xml";
HashMap dataSource=new HashMap();
SAXReader saxReader = new SAXReader();
 try {
Document document = saxReader.read(new File(dataSourcePath));

Node _hostAddress=document.selectSingleNode("/dataSource/hostAddress");
Node _databaseName=document.selectSingleNode("/dataSource/databaseName");
Node _userName=document.selectSingleNode("/dataSource/userName");
Node _password=document.selectSingleNode("/dataSource/password");

dataSource.put("hostAddress",_hostAddress.getText());
dataSource.put("databaseName", _databaseName.getText());
dataSource.put("userName",_userName.getText());
dataSource.put("password",_password.getText());

} catch (DocumentException e) {
e.printStackTrace();
}
return dataSource;
}

Answer 2

import java.io.File;
import java.io.IOException;
import java.util.List;import org.jdom.Attribute;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
public class Test1 {
private String outString="";
public Test1(String xmlPath){
SAXBuilder sb=new SAXBuilder();
Document doc=null;
try {
doc=sb.build(Thread.currentThread().getContextClassLoader().getResourceAsStream(xmlPath));
} catch (JDOMException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Element rootElem=doc.getRootElement();
PrintContent(rootElem);
}
private void PrintContent(Element elem){
List list=elem.getChildren();
for (Object e : list) {
Element el=(Element)e;
PrintContent(el);
}
if(!elem.getAttributes().isEmpty()){
outString+=elem.getName()+":"+((Attribute)elem.getAttributes().get(0)).getValue()+"\n";
}
if(elem.getChildren().isEmpty()){
outString+=elem.getName()+":"+elem.getValue()+"\n";
}
}
public String getString(){
return outString;
}
public static void main(String[] args){
Test1 test=new Test1("NewFile1.xml");
System.out.println(test.getString());
}
}

Answer 3

import java.io.File;
import java.io.IOException;
import java.util.List;import org.jdom.Attribute;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;public class Test1 {
        private String outString = "";        public Test1(String xmlPath) {
                SAXBuilder sb = new SAXBuilder();
                Document doc = null;
                try {
                        doc = sb.build(Thread.currentThread().getContextClassLoader()
                                        .getResourceAsStream(xmlPath));
                } catch (JDOMException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }                catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }
                Element rootElem = doc.getRootElement();
                PrintContent(rootElem);
        }        private void PrintContent(Element elem) {
                List list = elem.getChildren();
                for (Object e : list) {
                        Element el = (Element) e;
                        PrintContent(el);
                }
                if (!elem.getAttributes().isEmpty()) {
                        outString += elem.getName() + ":"
                                        + ((Attribute) elem.getAttributes().get(0)).getValue()
                                        + "\n";
                }
                if (elem.getChildren().isEmpty()) {
                        outString += elem.getName() + ":" + elem.getValue() + "\n";
                }
        }        public String getString() {
                return outString;
        }        public static void main(String[] args) {
                Test1 test = new Test1("NewFile1.xml");
                System.out.println(test.getString());
        }
}