Android: Dom parsing XML

Android: Dom parsing XML

Unlike the parsing of SAX and PULL, Dom parsing loads all XML files and assembles them into a Dom tree. Then, XML files are parsed through the relationship between nodes and nodes, occupying a large amount of memory, it is generally recommended to use SAX and PULL for parsing. Use the same example as above for analysis.

First, define an XML file: Student. xml. Note that the file is created instead of xml.

   
       
            
   
    
Zhang San
             
   
    
Male
   18      
        
            
   
    
Li Si
             
   
    
Female
   19      
        
            
   
    
Wang Wu
             
   
    
Male
   20      
    
   

Create a student class

package com.example.xml_sax_demo_1;public class Student {private int id;private String name;private int age;private String sex;public Student() {// TODO Auto-generated constructor stub}public int getId() {return id;}public Student(int id, String name, int age) {super();this.id = id;this.name = name;this.age = age;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}@Overridepublic String toString() {return "Student [id=" + id + ", name=" + name + ",sex=" + sex+ ", age=" + age + "]";}}

Finally, a Button is used in the activity to parse the data, which uses several classes.

Package com. example. xml_sax_demo_1; import java. io. inputStream; import java. util. arrayList; import java. util. list; import javax. xml. parsers. documentBuilder; import javax. xml. parsers. documentBuilderFactory; import org. w3c. dom. document; // note that the packages used are org. w3c. dom. * import org. w3c. dom. element; import org. w3c. dom. node; import org. w3c. dom. nodeList; import android. OS. bundle; import android. support. v7.app. actionBarActivity; import android. view. view; import android. view. view. onClickListener; import android. widget. button; public class MainActivity extends ActionBarActivity {@ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. activity_main); Button button = (Button) findViewById (R. id. button); button. setOnClickListener (new OnClickListener () {@ Overridepublic void onClick (View arg0) {// TODO Auto-generated method stubtry {readXML ();} catch (Exception e) {// TODO Auto-generated catch blocke. printStackTrace () ;}});} private void readXML () throws Exception {List
 
  
List = new ArrayList
  
   
(); InputStream stream = this. getClass (). getClassLoader (). getResourceAsStream ("Student. xml "); // obtain the input stream DocumentBuilderFactory factory = DocumentBuilderFactory. newInstance (); // DocumentBuilder builder = factory step by step. newDocumentBuilder (); Document document = builder. parse (stream); Element element = document. getDocumentElement (); // instantiate the element NodeList nodeList = element. getElementsByTagName ("student"); // obtain the node list for (int I = 0; I <nodeList. getLength (); I ++) {Element studentElement = (Element) nodeList. item (I); // corresponding to the list obtained above Student student = new Student (); // each node instantiates a student element student. setId (Integer. parseInt (studentElement. getAttribute ("id"); // get the attribute NodeList childNodeList = studentElement. getChildNodes (); // obtain the subnode list for (int j = 0; j <childNodeList. getLength (); j ++) {// if (childNodeList. item (j ). getNodeType () = Node. ELEMENT_NODE) // {if (childNodeList. item (j ). getNodeName (). equals ("name") {// If the subnode name is name student. setName (childNodeList. item (j ). getFirstChild () // store text data. getNodeValue ();} else if (childNodeList. item (j ). getNodeName (). equals ("sex") {student. setSex (childNodeList. item (j ). getFirstChild (). getNodeValue ();} else if (childNodeList. item (j ). getNodeName (). equals ("age") {student. setAge (Integer. parseInt (childNodeList. item (j ). getFirstChild (). getNodeValue ();} //} list. add (student); // add a student object to the list} for (Student stu: list) {System. out. println (stu. toString ());}}}
  
 

Result

Conclusion: The Code shows that Dom parsing loads all XML files, assembles them into a Dom tree, And parses XML files through the relationship between nodes and nodes, it is usually a continuous loop traversal, occupying a large amount of memory.