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在assets目录下创建一个文件名为students.xml的XML文件.
<?xml version="1.0" encoding="UTF-8"?>
<students>
<student id="101">
<name>小明</name>
<age>18</age>
</student>
<student id="102">
<name>小李</name>
<age>19</age>
</student>
</students>
- 创建一个与XML中节点相对应的bean类Student.java
public class Student{
//学号
private int id;
//姓名
private String name;
//年龄
private String age;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
@Override
public String toString() {
return "学生： 年龄=" + age + ", 姓名=" + name + "；";
}
}
- 创建一个接口StudentParser，每种类型的解析器需要实现此接口。
public interface StudentParser {
/**
* 解析输入流 得到Student对象集合
* @param is
* @return
* @throws Exception
*/
public List<Student> parse(InputStream is) throws Exception;
/**
* 序列化Student对象集合 得到XML形式的字符串
* @param students
* @return
* @throws Exception
*/
public String serialize(List<Student> students) throws Exception;
}
- 使用PULL解析器创建一个接口StudentParser的实现类StudentParser Impl
public class StudentParserImpl implements StudentParser{
@Override
public List<Student> parse(InputStream is) throws Exception {
List<Student> mList = null;
Student student= null;
// 由android.util.Xml创建一个XmlPullParser实例
XmlPullParser parser = Xml.newPullParser();
// 设置输入流 并指明编码方式
parser.setInput(is,"UTF-8");
// 产生第一个事件
int eventType = parser.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT){
switch (eventType) {
// 判断当前事件是否为文档开始事件
case XmlPullParser.START_DOCUMENT:
mList = new ArrayList<Student>(); // 初始化Student集合
break;
// 判断当前事件是否为标签元素开始事件
case XmlPullParser.START_TAG:
if (parser.getName().equals("student")) { // 判断开始标签元素是否是student
student = new Student();
} else if (parser.getName().equals("id")) {
eventType = parser.next();
student.setId(Integer.parseInt(parser.getText()));
} else if (parser.getName().equals("name")) {
eventType = parser.next();//让解析器指向name属性的值
// 得到name标签的属性值，并设置student的name
student.setName(parser.getText());
} else if (parser.getName().equals("age")) {
eventType = parser.next();//让解析器指向age属性的值
// 得到age标签的属性值，并设置student的age
student.setAge(parser.getText());
}
break;
// 判断当前事件是否为标签元素结束事件
case XmlPullParser.END_TAG:
if (parser.getName().equals("student")) { // 判断结束标签元素是否是student
mList.add(student); // 将student添加到students集合
student = null;
}
break;
}
// 进入下一个元素并触发相应事件
eventType = parser.next();
}
return mList;
}
@Override
public String serialize(List<Student> students) throws Exception {
// TODO Auto-generated method stub
XmlSerializer serializer = Xml.newSerializer(); //由android.util.Xml创建一个XmlSerializer实例
StringWriter writer = new StringWriter();
serializer.setOutput(writer); //设置输出方向为writer
serializer.startDocument("UTF-8", true);
serializer.startTag("", "students");
for (Student student : students) {
serializer.startTag("", "student");
serializer.attribute("", "id", student .getId() + "");
serializer.startTag("", "name");
serializer.text(student.getName());
serializer.endTag("", "name");
serializer.startTag("", "price");
serializer.text(student.getPrice() + "");
serializer.endTag("", "price");
serializer.endTag("", "student");
}
serializer.endTag("", "students");
serializer.endDocument();
return writer.toString();
}
}
- 在MainActivity调用pull解析xml文件
public class MainActivity extends Activity {
private static final String TAG = "XML";
private StudentParser parser;
private List<Student> studnents;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button readBtn = (Button) findViewById(R.id.readBtn);
Button writeBtn = (Button) findViewById(R.id.writeBtn);
readBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
InputStream is = getAssets().open("students.xml");
parser = new StudentParser(); //创建StudentParser实例
students = parser.parse(is); //解析输入流
for (Student student : students) {
Log.i(TAG, student.toString());
}
} catch (Exception e) {
Log.e(TAG, e.getMessage());
}
}
});
writeBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
String xml = parser.serialize(students); //序列化
FileOutputStream fos = openFileOutput("students.xml", Context.MODE_PRIVATE);
fos.write(xml.getBytes("UTF-8"));
} catch (Exception e) {
Log.e(TAG, e.getMessage());
}
}
});
}
}
