Printing out all the objects in array list
Solution 1
Override toString()
method in Student
class as below:
@Override
public String toString() {
return ("StudentName:"+this.getStudentName()+
" Student No: "+ this.getStudentNo() +
" Email: "+ this.getEmail() +
" Year : " + this.getYear());
}
Solution 2
Whenever you print any instance of your class, the default
toString
implementation of Object
class is called, which returns the representation that you are getting.
It contains two parts: - Type
and Hashcode
So, in student.Student@82701e that you get as output ->
student.Student
is theType
, and82701e
is theHashCode
So, you need to override a toString
method in your Student
class to get required String representation
: -
@Override
public String toString() {
return "Student No: " + this.getStudentNo() +
", Student Name: " + this.getStudentName();
}
So, when from your main
class, you print your ArrayList
, it will invoke the toString
method for each instance, that you overrided
rather than the one in Object
class: -
List<Student> students = new ArrayList();
// You can directly print your ArrayList
System.out.println(students);
// Or, iterate through it to print each instance
for(Student student: students) {
System.out.println(student); // Will invoke overrided `toString()` method
}
In both the above cases, the toString
method overrided in Student
class will be invoked and appropriate representation of each instance will be printed.
Solution 3
You have to define public String toString()
method in your Student
class. For example:
public String toString() {
return "Student: " + studentName + ", " + studentNo;
}
joe
Updated on July 09, 2022Comments
-
joe almost 2 years
I need to be able to print out the Student objects(all variables) in my array list. Is this possible? When i try to print it outputs this sort of thing e.g
student.Student@82701e
. I think it'shexadecimal
or somethingThis is my code:
package student; public class Student { private String studentName; private String studentNo; private String email; private int year; public Student() { this.studentName = null; this.studentNo = null; this.email = null; this.year = -1; } public Student(String nName, String nNum, String nEmail, int nYr) { this.studentName = nName; this.studentNo = nNum; this.email = nEmail; this.year = nYr; } public void setStudentName(String newStudentName) { this.studentName = newStudentName; } public void setStudentNo(String newStudentNo) { this.studentNo = newStudentNo; } public void setEmail(String newEmail) { this.email = newEmail; } public void setYear(int newYear) { this.year = newYear; } public String getStudentName() { return studentName; } public String getStudentNo() { return studentNo; } public String getEmail() { return email; } public int getYear() { return year; } } package student; import java.util.ArrayList; import java.util.List; import java.util.Scanner; public class studentTest { public static void main(String[] args) { Scanner input = new Scanner(System.in); List<Student> Students = new ArrayList(); Student student1 = new Student(); student1.setStudentName("Bob Marley"); student1.setStudentNo("N0002"); student1.setEmail("[email protected]"); student1.setYear(2); Students.add(student1); Student student2 = new Student(); student2.setStudentName("Bill Harvey"); student2.setStudentNo("N0003"); student2.setEmail("[email protected]"); student2.setYear(2); Students.add(student2); Student student3 = new Student(); student3.setStudentName("John Beans"); student3.setStudentNo("N0004"); student3.setEmail("[email protected]"); student3.setYear(2); Students.add(student3); System.out.println("Add new students: "); System.out.println("Enter number of students to add: "); int countStudents = input.nextInt(); for (int i = 0; i < countStudents; i++) { Student newStudents = new Student(); System.out.println("Enter details for student: " + (i + 1)); System.out.println("Enter name: "); newStudents.setStudentName(input.next()); System.out.println("Enter Number: "); newStudents.setStudentNo(input.next());System.out.println("Search by student number: "); System.out.println("Enter email: "); newStudents.setEmail(input.next()); System.out.println("Enter year: "); newStudents.setYear(input.nextInt()); Students.add(newStudents); } } }