XML解析详解

SAX是一种占用内存少且解析速度快的解析器，它采用的是事件启动，它不需要解析完整个文档，而是按照内容顺序 看文档某个部分是否符合xml语法，如果符合就触发相应的事件，所谓的事件就是些回调方法（callback）,这些方法 定义在ContentHandler中，下面是其主要方法：

startDocument:当遇到文档的时候就触发这个事件 调用这个方法 可以在其中做些预处理工作

startElement: (String namespaceURI,String localName,String qName,Attributes atts)当遇开始标签的时候就会触发这个方法。

endElement（String uri,String localName,String name）：当遇到结束标签时触发这个事件，调用此法可以做些善后工作。

charachers(char [] ch,int start,int length):当遇到xml内容时触发这个方法，用new String(ch,start,length)可以接受内容。 

首先在 res目录下新建一个raw文件夹，然后再里面么新建一个student.xml

代码片段(5)

[代码] student.xml

01<?xmlversion="1.0"encoding="utf-8"?>   

02<stundets> 

03  <studentid="2009081315"> 

04    <name>饶伟</name> 

05    <speciality>计算机科学与技术</speciality> 

06    <qq>812200157</qq> 

07  </student> 

08   

09    <studentid="2009081316"> 

10    <name>小伟</name> 

11    <speciality>网络工程</speciality> 

12    <qq>812200156</qq> 

13  </student> 

14    <studentid="2009081318"> 

15    <name>伟哥</name> 

16    <speciality>软件工程</speciality> 

17    <qq>812200158</qq> 

18  </student> 

19   

20</stundets>

[代码] Student.java

01public classStudent { 

02 

03long Id; 

04String Name; 

05String Speciality; 

06long QQ; 

07   

08public Student(longid, String name, String speciality, longqQ) { 

09    super(); 

10    Id = id; 

11    Name = name; 

12    Speciality = speciality; 

13    QQ = qQ; 

14} 

15 

16public Student() { 

17    super(); 

18} 

19 

20   

21public longgetId() { 

22    returnId; 

23} 

24 

25public String getName() { 

26    returnName; 

27} 

28 

29public longgetQQ() { 

30    returnQQ; 

31} 

32 

33public String getSpeciality() { 

34    returnSpeciality; 

35} 

36 

37public voidsetId(long id) { 

38    Id = id; 

39} 

40 

41public voidsetName(String name) { 

42    Name = name; 

43} 

44 

45public voidsetQQ(long qQ) { 

46    QQ = qQ; 

47} 

48 

49public voidsetSpeciality(String speciality) { 

50    Speciality = speciality; 

51} 

52 

53}

[代码] StudentHandler.java

01package rw.Xml_SAX; 

02   

03import java.util.List; 

04   

05import org.xml.sax.Attributes; 

06import org.xml.sax.SAXException; 

07import org.xml.sax.helpers.DefaultHandler; 

08   

09import Android.util.Log; 

10   

11public classStudentHandler extends DefaultHandler { 

12   

13   

14    privateString preTAG;   

15    privateList<Student> ListStudent; 

16    privateStudent stu; 

17       

18    publicStudentHandler() { 

19        super(); 

20    } 

21   

22    publicStudentHandler(List<Student> listStudent) { 

23        super(); 

24        ListStudent = listStudent; 

25    } 

26   

27   

28    publicvoid startDocument() throwsSAXException { 

29        // TODO Auto-generated method stub  

30    Log.i("------>","文档开始"); 

31        super.startDocument(); 

32    } 

33   

34    publicvoid startElement(String uri, String localName, String qName, 

35            Attributes attributes)throws SAXException { 

36   

37   

38        Log.i("localName-------->", localName); 

39        preTAG=localName; 

40        if("student".equals(localName)) { 

41            stu=newStudent(); 

42            stu.setId(Long.parseLong(attributes.getValue(0))); 

43               

44        for(int i = 0; i < attributes.getLength(); i++) { 

45            //Log.i("attributes-------->", attributes.getValue(i));  

46            Log.i("attributes-------->",String.valueOf(stu.getId())); 

47        } 

48    } 

49        super.startElement(uri, localName, qName, attributes); 

50    } 

51   

52    publicvoid endDocument() throwsSAXException { 

53       

54        Log.i("------>","文档结束"); 

55        super.endDocument(); 

56    } 

57   

58    publicvoid endElement(String uri, String localName, String qName) 

59            throwsSAXException { 

60        preTAG=""; 

61        if("student".equals(localName)) { 

62        ListStudent.add(stu); 

63        Log.i("-------->","一个元素解析完成"); 

64        } 

65        super.endElement(uri, localName, qName); 

66    } 

67       

68       

69public voidcharacters(char[] ch,int start, intlength) 

70        throwsSAXException { 

71       

72        String dateString; 

73       if("name".equals(preTAG)) { 

74            dateString=newString(ch,start,length); 

75            stu.setName(dateString); 

76            Log.i("name=", stu.getName()); 

77        }elseif ("speciality".equals(preTAG)) { 

78            dateString=newString(ch,start,length); 

79            stu.setSpeciality(dateString); 

80            Log.i("speciality=", stu.getSpeciality()); 

81        }elseif ("qq".equals(preTAG)) { 

82            dateString=newString(ch,start,length); 

83            stu.setQQ(Long.parseLong((dateString))); 

84            Log.i("QQ=", String.valueOf(stu.getQQ())); 

85        } 

86   

87        super.characters(ch, start, length); 

88} 

89   

90               

91public List<Student> getListStudent() { 

92    returnListStudent; 

93} 

94   

95public voidsetListStudent(List<Student> listStudent) { 

96    ListStudent = listStudent; 

97} 

98   

99}

[代码] XMl_Sax1Activity.java

01import java.util.ArrayList; 

02import java.util.Iterator; 

03import java.util.List; 

04 

05import javax.xml.parsers.SAXParserFactory; 

06 

07import org.xml.sax.InputSource; 

08import org.xml.sax.XMLReader; 

09 

10 

11import Android.app.Activity; 

12import Android.os.Bundle; 

13import Android.util.Log; 

14import Android.view.View; 

15import Android.view.View.OnClickListener; 

16import Android.widget.Adapter; 

17import Android.widget.ArrayAdapter; 

18import Android.widget.Button; 

19import Android.widget.ListView; 

20import Android.widget.TextView; 

21 

22public classXMl_Sax1Activity extends Activity { 

23  privateButton button; 

24  privateTextView textView; 

25  privateListView listView; 

26  privateList<String> list=new ArrayList<String>(); 

27public voidonCreate(Bundle savedInstanceState) { 

28    super.onCreate(savedInstanceState); 

29    setContentView(R.layout.main); 

30    button=(Button)findViewById(R.id.button1); 

31    textView=(TextView)findViewById(R.id.textView1); 

32    listView=(ListView) findViewById(R.id.listView1); 

33    //InputSource xMLResourceString=new InputSource(XMl_Sax1Activity.this.getResources().openRawResource(R.raw.student));  

34    button.setOnClickListener(newButtonListener()); 

35} 

36 

37class ButtonListenerimplements OnClickListener{ 

38 

39    @Override 

40    publicvoid onClick(View v) { 

41          

42       List<Student> students=parserXMl(); 

43       for(Iterator iterator = students.iterator(); iterator.hasNext();) { 

44       Student student = (Student) iterator.next(); 

45        list.add(String.valueOf(student.getId())+" "+student.getName()+" "+student.getSpeciality()+" "+String.valueOf((student.getQQ()))); 

46    } 

47      

48       ArrayAdapter<String> adapter=newArrayAdapter<String>(getApplicationContext(), Android.R.layout.simple_list_item_1, list); 

49       listView.setAdapter(adapter); 

50    } 

51       

52} 

53   

54private List<Student> parserXMl() 

55{ 

56    SAXParserFactory factory=SAXParserFactory.newInstance(); 

57    List<Student>students=null; 

58    Student student=null; 

59    try{ 

60    XMLReader reader=factory.newSAXParser().getXMLReader(); 

61    students=newArrayList<Student>(); 

62    reader.setContentHandler(newStudentHandler(students)); 

63    reader.parse(newInputSource(XMl_Sax1Activity.this.getResources().openRawResource(R.raw.student))); 

64    for(Iterator iterator = students.iterator(); iterator.hasNext();) { 

65         student = (Student) students.iterator();    

66    } 

67    students.add(student); 

68    } catch (Exception e) { 

69    // TODO: handle exception  

70    } 

71    returnstudents; 

72} 

73}

[代码] 布局文件main.xml

01<?xmlversion="1.0"encoding="utf-8"?> 

02<LinearLayoutxmlns:Android="http://schemas.android.com/apk/res/android" 

03    Android:orientation="vertical" 

04    Android:layout_width="fill_parent" 

05    Android:layout_height="fill_parent" 

06    > 

07   

08<ButtonAndroid:text="SAX解析"android:id="@+id/button1"android:layout_height="wrap_content"android:layout_width="match_parent"></Button> 

09<TextViewAndroid:text=""android:id="@+id/textView1"android:layout_width="wrap_content"android:layout_height="wrap_content"></TextView> 

10<ListViewAndroid:layout_height="wrap_content"android:id="@+id/listView1"android:layout_width="match_parent"></ListView> 

11</LinearLayout>