DOM解析器讀取Xml，檢索屬性值並存儲它們

Question

使用DOM解析器，我將屬性值存儲在Java中的HashMap中，然後根據需要進行檢索。有沒有其他的方式來做到這一點，而不使用地圖？

XML例子

<?xml version="1.0" encoding="UTF-8"?> 
<Main> 
    <SubMainLevels> 
     <SubMainLevel LineNo="1" arg2="122" RollNo="11" weight="14" folds="1" /> 
     <SubMainLevel LineNo="2" arg2="123" RollNo="12" weight="12" folds="2" /> 
    </SubMainLevels> 
</Main> 

我做了什麼

Map<String, String> x = new HashMap<String, String>(); 
    getXmlAttr(){ 
    Traverse till Main\SubMainLevels\SubMainLevel  

    for each SubMainLevel {  
     getAttribute() for all attributes LineNo,arg2,RollNo,weight,folds 
     concatenate strConcat = arg2+":"+RollNo+":"+weight+":"+folds 
     x.put(LineNo,strConcat); 
    } 
    } 




reteriveAttrMap(HashMap x){ 
    for each HashMap key{ 
     strVal =x.get(key) 
     split strVal at ":" 
     //do stuff 
    } 
} 

Answer 1

可以使用POJO類來存儲屬性，而不是僅僅使用字符串。

此程序使用BeanUtils將屬性填充到bean中。

下面是代碼

import java.io.FileInputStream; 
import java.lang.reflect.InvocationTargetException; 
import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 
import java.util.Map; 

import javax.xml.parsers.DocumentBuilder; 
import javax.xml.parsers.DocumentBuilderFactory; 

import org.apache.commons.beanutils.BeanUtils; 
import org.w3c.dom.Document; 
import org.w3c.dom.Element; 
import org.w3c.dom.NamedNodeMap; 
import org.w3c.dom.Node; 

public class DOMParsarDemo2 { 
    protected DocumentBuilder docBuilder; 
    protected Element root; 

    private static List<SubMainLevel> subMainLevels = new ArrayList<SubMainLevel>(); 

    public DOMParsarDemo2() throws Exception { 
     DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 
     docBuilder = dbf.newDocumentBuilder(); 
    } 

    public void parse(String file) throws Exception { 
     Document doc = docBuilder.parse(new FileInputStream(file)); 
     root = doc.getDocumentElement(); 
     System.out.println("root element is :" + root.getNodeName()); 
    } 

    public void printAllElements() throws Exception { 
     printElement(root); 
    } 

    public void printElement(Node node) { 
     if (node.getNodeType() != Node.TEXT_NODE) { 
      Node child = node.getFirstChild(); 
      while (child != null) { 
       if ("SubMainLevel".equals(child.getNodeName())) { 
        NamedNodeMap namedNodeMap = child.getAttributes(); 

        Map<String, String> attrMap = new HashMap<String, String>(); 
        for (int i = 0; i < namedNodeMap.getLength(); i++) { 
         Node n = namedNodeMap.item(i); 
         attrMap.put(n.getNodeName(), n.getNodeValue()); 
        } 

        SubMainLevel subMainLevel = new SubMainLevel(); 
        try { 
         BeanUtils.populate(subMainLevel, attrMap); 
        } catch (IllegalAccessException e) { 
         e.printStackTrace(); 
        } catch (InvocationTargetException e) { 
         e.printStackTrace(); 
        } 
        subMainLevels.add(subMainLevel); 
       } 
       printElement(child); 
       child = child.getNextSibling(); 
      } 
     } 
    } 

    public static void main(String args[]) throws Exception { 
     DOMParsarDemo2 demo = new DOMParsarDemo2(); 
     demo.parse("resources/abc1.xml"); 
     demo.printAllElements(); 

     for (SubMainLevel subMainLevel : subMainLevels) { 
      System.out.println(subMainLevel); 
     } 
    } 
} 

POJO：

import java.io.Serializable;  

public class SubMainLevel implements Serializable { 

    private static final long serialVersionUID = 1L; 

    public SubMainLevel() { 

    } 

    private String LineNo; 
    private String arg2; 
    private String RollNo; 
    private String weight; 
    private String folds; 

    public String getLineNo() { 
     return LineNo; 
    } 

    public void setLineNo(String lineNo) { 
     LineNo = lineNo; 
    } 

    public String getArg2() { 
     return arg2; 
    } 

    public void setArg2(String arg2) { 
     this.arg2 = arg2; 
    } 

    public String getRollNo() { 
     return RollNo; 
    } 

    public void setRollNo(String rollNo) { 
     RollNo = rollNo; 
    } 

    public String getWeight() { 
     return weight; 
    } 

    public void setWeight(String weight) { 
     this.weight = weight; 
    } 

    public String getFolds() { 
     return folds; 
    } 

    public void setFolds(String folds) { 
     this.folds = folds; 
    } 

    @Override 
    public String toString() { 
     return "LineNo=" + getLineNo() + " arg2=" + getArg2() + " RollNo=" + getRollNo() 
       + " weight=" + getWeight() + " folds=" + getFolds(); 
    } 

}