Dom与Pull方式解析XML文件

1. Dom方式解析

public class DomStudentService
{
 public static List<Student> readStudentXML(InputStream input)
 {
  try
  {
   List<Student> list = new ArrayList<Student>();
   Student stu = null;
   DocumentBuilderFactory domBuilderFactory = DocumentBuilderFactory.newInstance();
   DocumentBuilder domBuilder = domBuilderFactory.newDocumentBuilder();
   Document dom = domBuilder.parse(input);
   Element root = dom.getDocumentElement();
   NodeList stuList = root.getElementsByTagName("Student");
   for(int i = 0; i < stuList.getLength(); i++)
   {
    stu = new Student();
    Element stuNode = (Element)stuList.item(i);  /* Element继承自Node，并不是每个Node都是Element，/n/t也是Node */
    
    /*set id*/
    stu.setId(stuNode.getAttribute("id"));  /*获取属性值*/
    
    NodeList stuChilds = stuNode.getChildNodes();
    for(int j = 0; j < stuChilds.getLength(); j++)
    {
     if(stuChilds.item(j).getNodeType() != Node.ELEMENT_NODE)        /* 判断Node类型是否为Element */

     {
      continue ;
     }
     
     Node childElement = stuChilds.item(j);
     /*set name*/
     if("name".equals(childElement.getNodeName()))
     {
      stu.setName(childElement.getFirstChild().getNodeValue());       /*获取标签内的文本*/
     }
     /*set age*/
     else if("age".equals(childElement.getNodeName()))
     {
      stu.setAge(Integer.parseInt(childElement.getFirstChild().getNodeValue()));
     }
    }
    list.add(stu);
   }
   return list;
  }
  catch(Exception e)
  {
   e.printStackTrace();
  }
  return null;
 }
}

 

2.Pull方式解析

pull方式基本与SAX方式一致，事件是由自己触发，性能比较高，与SAX差不多。

public static List<Student> readStudentXml(InputStream input)
 {
  List<Student> list = null;
  Student stu = null;
  try
  {
   XmlPullParserFactory pullParserFactory = XmlPullParserFactory.newInstance();
   XmlPullParser pullParser = pullParserFactory.newPullParser();
   pullParser.setInput(input, "UTF-8");

  int type = pullParser.getEventType(); /*第一次获取事件*/
   while(type != XmlPullParser.END_DOCUMENT) /*遇到文档结束事件，循环终止*/
   {
    switch(type)
    {
    case XmlPullParser.START_DOCUMENT:  /*文档开始事件*/
     list = new ArrayList<Student>();
     break;
    case XmlPullParser.START_TAG:  /*标签开始事件*/
     if("Student".equals(pullParser.getName()))
     {
      stu = new Student();
      stu.setId(pullParser.getAttributeValue(null, "id"));
     }
     else if("name".equals(pullParser.getName()))
     {
      if(stu == null)
      {
       break;
      }
      stu.setName(pullParser.nextText());
     }
     else if("age".equals(pullParser.getName()))
     {
      if(stu == null)
      {
       break;
      }
      stu.setAge(Integer.parseInt(pullParser.nextText()));
     }
     break;
    case XmlPullParser.END_TAG: /*标签结束事件*/
     if("Student".equals(pullParser.getName()))
     {
      list.add(stu);
     }
     break;
    default:
     break;
    }
    type = pullParser.next();  /*迭代获取事件*/
   }
   return list;
  }
  catch(Exception e)
  {
   e.printStackTrace();
  }
  return null;
 }

   

 

 

3. Pull方式写XML

public static void WriteStudentXml(List<Student> list, OutputStream output)
 {
  try
  {
   XmlSerializer xmlSeri = Xml.newSerializer();/*创建XmlSerilizer*/
   xmlSeri.setOutput(output, "UTF-8");
   xmlSeri.startDocument("UTF-8", null); /*开始文档*/
   xmlSeri.startTag(null, "Students");      /*开始标签*/
   for(Student stu : list)
   {
    xmlSeri.startTag(null, "Student");
    xmlSeri.attribute(null, "id", stu.getId());        /*写属性*/
    xmlSeri.startTag(null, "name");
    xmlSeri.text(stu.getName());
    xmlSeri.endTag(null, "name");
    xmlSeri.startTag(null, "age");
    xmlSeri.text(((Integer)stu.getAge()).toString());
    xmlSeri.endTag(null, "age");
    xmlSeri.endTag(null, "Student");
   }
   xmlSeri.endTag(null, "Students");   /*结束标签*/
   xmlSeri.endDocument();               /*结束文档*/
   output.close();
  }
  catch(Exception e)
  {
   e.printStackTrace();
  }
 }