DOM 解析器读取 Xml ，检索属性值并存储它们

Question

使用 DOM 解析器，我将属性值存储在 Java 中的 HashMap 中，然后根据需要检索它。有没有其他不使用地图的方法？

Xml 示例：

<?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>

我做了什么：

   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);
     }
    }




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

Answer 1

您可以使用POJO 类来存储属性，而不仅仅是使用字符串。

这个程序正在使用BeanUtils 将属性填充到 bean 中。

这里是代码

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();
    }

}