Java でのデータアクセスオブジェクトの実装

//Product class
class Product {
	int id;
	String name;
	// add more values
}

public static void main(String[] args) {
		// Now let us insert new product
		// constructor PDAO class
		// objects
		ProDAO dao2 = new ProDAO(); // constructor
		Product pro = new Product(); // constructor
		// values to insert
		// dynamically modify values from here later
		pro.id = 3;
		pro.name = "Oppo LOL";
		// we have created a separate function for the db connection
		dao2.Dbconnect();
		// it is set to addProduct as of now, you can run CRUD directly from here
		dao2.addProduct(pro);
}

// Database Connection will use jdbc driver from the mysql connector jar
public void Dbconnect() {
		try {
			Class.forName("com.mysql.cj.jdbc.Driver");//Mysql Connector's JDBC driver is loaded
			// connection to mysql
			con = DriverManager.getConnection("jdbc:mysql://localhost/mydb", "root", ""); // URL, database name after
			// localhost, user name,
			// password
		} catch (Exception ex) {
			System.out.println(ex);
		}
}

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;

//This Data Access Object DAO is a dynamic way to handle database records.

//main class
class DAOexample {
	public static void main(String[] args) {
		// Now let us insert new product
		// constructor PDAO class
		// objects
		ProDAO dao2 = new ProDAO(); // constructor
		Product pro = new Product(); // constructor
		// values to insert
		// dynamically modify values from here later
		pro.id = 3;
		pro.name = "Oppo LOL";
		// we have created a separate function for the db connection
		dao2.Dbconnect();
		// it is set to addProduct as of now, you can run CRUD directly from here
		dao2.addProduct(pro);
	}
}

class ProDAO {
	Connection con = null;

	// Database Connection will use jdbc driver from the mysql connector jar
	public void Dbconnect() {
		try {
			Class.forName("com.mysql.cj.jdbc.Driver");
			// connection to mysql
			con = DriverManager.getConnection("jdbc:mysql://localhost/mydb", "root", ""); // URL, database name after
			// localhost, user name,
			// password
		} catch (Exception ex) {
			System.out.println(ex);
		}
	}

	// We will use the insert operation in this function, its conductor is already
	// declared in the main class (DAO)
	public void addProduct(Product p) { // this function will insert values
		// insert query
		// using prepared statements
		String query2 = "insert into products values (?,?)";
		try {
			PreparedStatement pst;
			pst = con.prepareStatement(query2);
			pst.setInt(1, p.id);
			pst.setString(2, p.name); //
			pst.executeUpdate(); // executeUpdate is used for the insertion of the data
			System.out.println("Inserted!");
		} catch (Exception ex) {
		}
	}
}

//Product class
class Product {
	int id;
	String name;
	// add more values
}