view.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;

class view extends JFrame{
	Container c;
	TextArea taData;
	JButton btnBack;

	view(){
		c = getContentPane();
		c.setLayout(new FlowLayout(FlowLayout.CENTER,20,20));
		
		taData = new TextArea(12,30);
		taData.setEditable(false);
		btnBack = new JButton("Back to Main");

		Font f = new Font("Times New Roman",Font.PLAIN,20);
		Font t = new Font("Times New Roman",Font.BOLD,20);
		taData.setFont(f);
		btnBack.setFont(t);
	
		c.add(taData);
		c.add(btnBack);

		class Eh1 implements ActionListener{
			public void actionPerformed(ActionEvent ae){
				dashboard a = new dashboard();
				dispose();
			}
		}
		btnBack.addActionListener(new Eh1());

				String user = System.getenv("DB_USER");
				String pwd = System.getenv("DB_PASSWORD");
				String url = "jdbc:mysql://localhost:3306/student_db";
				taData.setText("Name\tRollno\tCourse\t\tMarks\n");
				taData.append("-------------------------------------------------------------\n");
				try{
					DriverManager.registerDriver(new com.mysql.cj.jdbc.Driver());
					try(Connection con = DriverManager.getConnection(url,user,pwd);
					PreparedStatement pst = con.prepareStatement("select * from student");
					ResultSet rs = pst.executeQuery()){
					while (rs.next()) {
						int rno = rs.getInt("rno");
						String name = rs.getString("name");
						int marks = rs.getInt("marks");
						String course = rs.getString("course");
						taData.append(name + "\t\t" + rno + "\t\t" + course + "\t\t" + marks +"\n");
					}
					} catch(SQLException e){
						String msg = "issue " + e;
						JOptionPane.showMessageDialog(c,msg);
					}
				} catch(SQLException e){
					String msg = "issue " + e;
					JOptionPane.showMessageDialog(c,msg);
				}

		setSize(500,450);
		setLocationRelativeTo(null);
		setTitle("Database");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
	}
}