Khoá học lập trình Java Core nâng cao [Video] Tìm hiểu XML & Hướng dẫn phân tích tài liệu XML quản lý lớp học bằng Java

Phần nội dung:

1. Thiết kế tài liệu XML

=> mindset => tạo class object

2. Thực hành đc

=> Phân tích tài liệu XML => biến thành class object

=> Java => phân tích tài liệu XML => class object

Phân tích:

Công nghệ sử dụng:

XML => phân tích dữ liệu (đọc dữ liệu từ XML) => Parser (Library - Java, PHP, NodeJS, ...)

Parser 

=> DOM Parser

=> Ưu điểm: Phân tích được tất cả các loại tài liệu XML => ko cần biết trc cấu trúc của XML

=> Nhược:

- Trậm, tốn tài nguyên

=> JAX Parser

=> Ưu điểm: nhẹ chương trình, nhanh

=> Nhược: Mỗi một tài liệu XML => xây dựng 1 JAX tương ứng cho tài liệu đó. Biết trc cấu trúc của XML cần phân tích

=> Sử dụng cái này.

Thuật ngữ sử dụng:

XPath

class_list/class/classname => dữ liệu trả về là gì (DOM Parser)

=> phần tử đầu

Xây dựng dự án Java:

- Đầu vào là file student.xml

- Phân tích cấu trúc xml => mapping class object tương ứng

- Xây dựng Jax parser => chuyển student.xml => object trong java

- Xay dung Parser cho student.xml

- Đầu ra của chúng ta => object trong java

Source Code

/*
 * 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 lession1;

import java.io.FileInputStream;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

/**
 *
 * @author Diep.Tran
 */
public class Main {
    public static void main(String[] args) throws Exception {
        //doc noi dung tu file xml.
        FileInputStream fis = new FileInputStream("aptech_class.xml");
        
        SAXParserFactory factory = SAXParserFactory.newInstance();
	SAXParser saxParser = factory.newSAXParser();
        
        AptechClassHandler aptechClassHandler = new AptechClassHandler();
        
        saxParser.parse(fis, aptechClassHandler);
        
        aptechClassHandler.display();
    }
}

/*
 * 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 lession1;

import java.util.ArrayList;
import java.util.List;

/**
 *
 * @author Diep.Tran
 */
public class AptechClass {
    String classname, address;
    Teacher teacher;
    List<Student> studentList = new ArrayList<>();

    public AptechClass() {
    }

    public String getClassname() {
        return classname;
    }

    public void setClassname(String classname) {
        this.classname = classname;
    }

    public String getAddress() {
        return address;
    }

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

    public Teacher getTeacher() {
        return teacher;
    }

    public void setTeacher(Teacher teacher) {
        this.teacher = teacher;
    }

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

    public void setStudentList(List<Student> studentList) {
        this.studentList = studentList;
    }
    
    public void display() {
        System.out.format("\nClass Name: %s, Address: %s", classname, address);
        System.out.println("Teacher's Detail information: ");
        System.out.println(teacher);
        System.out.println("Student List: ");
        for (Student student : studentList) {
            System.out.println(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 lession1;

/**
 *
 * @author Diep.Tran
 */
public class Teacher {
    String fullname, address;
    int age;

    public Teacher() {
    }

    public Teacher(String fullname, String address, int age) {
        this.fullname = fullname;
        this.address = address;
        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 int getAge() {
        return age;
    }

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

    @Override
    public String toString() {
        return "Teacher{" + "fullname=" + fullname + ", address=" + address + ", age=" + age + '}';
    }
}

/*
 * 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 lession1;

/**
 *
 * @author Diep.Tran
 */
public class Student {
    String fullname, address;
    int age;

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

    public Student() {
    }

    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 int getAge() {
        return age;
    }

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

    @Override
    public String toString() {
        return "Student{" + "fullname=" + fullname + ", address=" + address + ", age=" + age + '}';
    }
}

/*
 * 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 lession1;

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 Diep.Tran
 */
public class AptechClassHandler extends DefaultHandler{
    List<AptechClass> classList = new ArrayList<>();
    AptechClass currentClass = null;
    Student currentStudent = null;
    
    boolean isClassName = false;
    boolean isAddress = false;
    boolean isTeacher = false;
    boolean isFullname = false;
    boolean isAge = false;
    boolean isStudent = false;
    
    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        if(qName.equalsIgnoreCase("class")) {
            currentClass = new AptechClass();
        } else if(qName.equalsIgnoreCase("classname")) {
            isClassName = true;
        } else if(qName.equalsIgnoreCase("address")) {
            isAddress = true;
        } else if(qName.equalsIgnoreCase("teacher")) {
            isTeacher = true;
            Teacher teacher = new Teacher();
            currentClass.setTeacher(teacher);
        } else if(qName.equalsIgnoreCase("fullname")) {
            isFullname = true;
        } else if(qName.equalsIgnoreCase("age")) {
            isAge = true;
        } else if(qName.equalsIgnoreCase("student")) {
            isStudent = true;
            currentStudent = new Student();
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if(qName.equalsIgnoreCase("class")) {
            classList.add(currentClass);
            currentClass = null;
        } else if(qName.equalsIgnoreCase("classname")) {
            isClassName = false;
        } else if(qName.equalsIgnoreCase("address")) {
            isAddress = false;
        } else if(qName.equalsIgnoreCase("teacher")) {
            isTeacher = false;
        } else if(qName.equalsIgnoreCase("fullname")) {
            isFullname = false;
        } else if(qName.equalsIgnoreCase("age")) {
            isAge = false;
        } else if(qName.equalsIgnoreCase("student")) {
            isStudent = false;
            currentClass.getStudentList().add(currentStudent);
            currentStudent = null;
        }
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        String value = new String(ch, start, length);
        
        if(isClassName) {
            currentClass.setClassname(value);
        } else if(isAddress) {
            if(isTeacher) {
                currentClass.getTeacher().setAddress(value);
            } else if(isStudent) {
                currentStudent.setAddress(value);
            } else {
                currentClass.setAddress(value);
            }
        } else if(isFullname) {
            if(isTeacher) {
                currentClass.getTeacher().setFullname(value);
            } else if(isStudent) {
                currentStudent.setFullname(value);
            }
        } else if(isAge) {
            if(isTeacher) {
                currentClass.getTeacher().setAge(Integer.parseInt(value));
            } else if(isStudent) {
                currentStudent.setAge(Integer.parseInt(value));
            }
        }
    }
    
    public void display() {
        for (AptechClass aptechClass : classList) {
            aptechClass.display();
        }
    }
}

<?xml version="1.0" encoding="UTF-8"?>

<class_list title="sdsd" abc="sasd">
	<class>
		<classname>T1907A</classname>
		<address>8 Ton That Thuyet, Cau Giay, HN</address>
		<teacher>
			<fullname>Tran Van A</fullname>
			<age>32</age>
			<address>Nam Dinh</address>
		</teacher>
		<student_list>
			<student>
				<fullname>Nguyen Van A</fullname>
				<age>18</age>
				<address>Ha Noi</address>
			</student>
			<student>
				<fullname>Nguyen Van B</fullname>
				<age>18</age>
				<address>Ha Noi</address>
			</student>
			<student>
				<fullname>Nguyen Van C</fullname>
				<age>18</age>
				<address>Ha Noi</address>
			</student>
		</student_list>
	</class>
	<class>
		<classname>T1907E</classname>
		<address>8 Ton That Thuyet, Cau Giay, HN</address>
		<teacher>
			<fullname>Tran Van B</fullname>
			<age>32</age>
			<address>Nam Dinh</address>
		</teacher>
		<student_list>
			<student>
				<fullname>Nguyen Van A</fullname>
				<age>18</age>
				<address>Ha Noi</address>
			</student>
			<student>
				<fullname>Nguyen Van B</fullname>
				<age>18</age>
				<address>Ha Noi</address>
			</student>
			<student>
				<fullname>Nguyen Van C</fullname>
				<age>18</age>
				<address>Ha Noi</address>
			</student>
		</student_list>
	</class>
</class_list>