Share Code - Hướng dẫn sử dụng Sax Parser phân tích tài liệu xml - danh sách sinh viên

Tài liệu xml >> Danh sách sinh viên

<?xml version="1.0" encoding="UTF-8"?>
<root>
	<studentList>
		<student>
			<fullname>Tran Van A</fullname>
			<age>22</age>
			<address>Ha Noi</address>
			<email>tranvandiep.it@gmail.com</email>
			<roll_no>R001</roll_no>
		</student>
		<student>
			<fullname>Tran Van B</fullname>
			<age>22</age>
			<address>Ha Noi</address>
			<email>tranvandiep.it@gmail.com</email>
			<roll_no>R001</roll_no>
		</student>
	</studentList>
</root>

Thực hiện tạo class Student với các thuộc tính như mô tả trong tài liệu XML

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package aptech;

/**
 *
 * @author DiepTV
 */
public class Student {
    String fullname, address, email, rollNo;
    int age;

    public Student() {
    }

    public Student(String fullname, String address, String email, String rollNo, int age) {
        this.fullname = fullname;
        this.address = address;
        this.email = email;
        this.rollNo = rollNo;
        this.age = age;
    }

    public String getFullname() {
        return fullname;
    }

    public void setFullname(String fullname) {
        this.fullname = fullname;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getRollNo() {
        return rollNo;
    }

    public void setRollNo(String rollNo) {
        this.rollNo = rollNo;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" + "fullname=" + fullname + ", address=" + address + ", email=" + email + ", rollNo=" + rollNo + ", age=" + age + '}';
    }
    
    public void display() {
        System.out.println(this);
    }
}

Viết một bộ phân tích SAX Parser => Thực hiện nhiệm vụ chuyển đổi dữ liệu từ tài liệu xml thành đối tượng Student

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package aptech;

import java.util.ArrayList;
import java.util.List;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 *
 * @author DiepTV
 */
public class StudentHandler extends DefaultHandler {

    List<Student> studentList;
    boolean isFullname = false, isAge = false, isEmail = false, isAddress = false, isRollNo = false;
    Student currentStudent;

    public StudentHandler() {
        studentList = new ArrayList<>();
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        if (qName.equalsIgnoreCase("Student")) {
            currentStudent = new Student();
        } else if (qName.equalsIgnoreCase("fullname")) {
            isFullname = true;
        } else if (qName.equalsIgnoreCase("Age")) {
            isAge = true;
        } else if (qName.equalsIgnoreCase("Email")) {
            isEmail = true;
        } else if (qName.equalsIgnoreCase("Address")) {
            isAddress = true;
        } else if (qName.equalsIgnoreCase("Roll_No")) {
            isRollNo = true;
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if (qName.equalsIgnoreCase("Student")) {
            studentList.add(currentStudent);
            currentStudent = null;
        } else if (qName.equalsIgnoreCase("fullname")) {
            isFullname = false;
        } else if (qName.equalsIgnoreCase("Age")) {
            isAge = false;
        } else if (qName.equalsIgnoreCase("Email")) {
            isEmail = false;
        } else if (qName.equalsIgnoreCase("Address")) {
            isAddress = false;
        } else if (qName.equalsIgnoreCase("Roll_No")) {
            isRollNo = false;
        }
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        if (currentStudent != null) {
            if (isFullname) {
                currentStudent.setFullname(new String(ch, start, length));
            } else if (isAge) {
                String ageStr = new String(ch, start, length);
                currentStudent.setAge(Integer.parseInt(ageStr));
            } else if (isEmail) {
                currentStudent.setEmail(new String(ch, start, length));
            } else if (isAddress) {
                currentStudent.setAddress(new String(ch, start, length));
            } else if (isRollNo) {
                currentStudent.setRollNo(new String(ch, start, length));
            }
        }
    }

    public List<Student> getStudentList() {
        return studentList;
    }

    public void setStudentList(List<Student> studentList) {
        this.studentList = studentList;
    }
}

Viết chương trình test. Nối các thành phần trong dự án.

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package aptech;

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.SAXException;

/**
 *
 * @author DiepTV
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        try {
            // TODO code application logic here
            File file = new File("student.xml");
            SAXParserFactory factory = SAXParserFactory.newInstance();
            SAXParser parser = factory.newSAXParser();
            
            StudentHandler studentHandler = new StudentHandler();
            
            parser.parse(file, studentHandler);
            
            //lay dc data
            List<Student> studentList = studentHandler.getStudentList();
            
            for (Student student : studentList) {
                student.display();
            }
        } catch (ParserConfigurationException ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        } catch (SAXException ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
    
}