How to get properties of an object stored in ArrayList using Java

Question

I want to print all student objects' properties(name, subject, registrationNo) stored in a ArrayList object.

student details are getting from a database and insert them into student objects. Then these student objects are insert into the ArrayList.

Finally I want to print these student object properties one by one as follows. Followings are my codes.

DBconn.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DBconn {

    static Connection conn;

    public static Connection getConnection() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            try {
                conn = DriverManager.getConnection("jdbc:mysql://localhost/student_database", "root", "");
            } catch (SQLException ex) {

            }
        } catch (ClassNotFoundException ex) {

        }
        return conn;
    }

}

Student.java

public class Student {

    private String name;
    private String RegistrationNo;
    private String course;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getRegistrationNo() {
        return RegistrationNo;
    }

    public void setRegistrationNo(String RegistrationNo) {
        this.RegistrationNo = RegistrationNo;
    }

    public String getCourse() {
        return course;
    }

    public void setCourse(String course) {
        this.course = course;
    }

}

StudentList.java

import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;

public class StudentList {

    public static ArrayList getStudentList() {
        ArrayList list = new ArrayList();

        String sql = "SELECT * FROM student";

        try {
            Statement stm = DBconn.getConnection().createStatement();
            ResultSet rs = stm.executeQuery(sql);

            while (rs.next()) {
                Student student = new Student();

                student.setName(rs.getString(1));
                student.setCourse(rs.getString(2));
                student.setRegistrationNo(rs.getString(3));

                list.add(student);
            }

        } catch (SQLException ex) {

        }
        return list;
    }

}

ViewStudent.java

public class ViewStudent {

    public static void main(String[] args) {

        int size = StudentList.getStudentList().size();
        for (int i = 0; i < size; i++) {
            System.out.println(StudentList.getStudentList().get(i));
      //I want to get all student's name,subject and registrationNo 

        }

    }

}

Thanks.

Just use your getters. Something like StudentList.getStudentList().get(i).getName() — dguay
– dguay, Commented Nov 26, 2015 at 18:12

Hovercraft Full Of Eels · Accepted Answer · 2015-11-26 18:12:34Z

5

Simply give Student a public String toString() method override, one that returns a String holding all key properties, and then this will work fine:

System.out.println(StudentList.getStudentList().get(i));

answered Nov 26, 2015 at 18:12

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Hovercraft Full Of Eels

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Comments

Preshan Pradeepa · Accepted Answer · 2015-11-26 19:42:07Z

3

Instead of System.out.println(StudentList.getStudentList().get(i));, you should access the student's properties and print it out.

Student s = (Student) StudentList.getStudentList().get(i);
System.out.println(s.getName());
System.out.println(s.getCourse());
System.out.println(s.getRegistrationNo());

edited Nov 26, 2015 at 19:42

Preshan Pradeepa

68314 silver badges31 bronze badges

answered Nov 26, 2015 at 18:16

Atri

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