how to sort objects arraylist code example
Example 1: how to sort the arraylist of objects in java
package beginnersbook.com;
import java.util.*;
public class Details {
public static void main(String args[]){
ArrayList<Student> arraylist = new ArrayList<Student>();
arraylist.add(new Student(101, "Zues", 26));
arraylist.add(new Student(505, "Abey", 24));
arraylist.add(new Student(809, "Vignesh", 32));
System.out.println("Student Name Sorting:");
Collections.sort(arraylist, Student.StuNameComparator);
for(Student str: arraylist){
System.out.println(str);
}
System.out.println("RollNum Sorting:");
Collections.sort(arraylist, Student.StuRollno);
for(Student str: arraylist){
System.out.println(str);
}
}
}
Example 2: how to sort the arraylist of objects in java
package beginnersbook.com;
import java.util.Comparator;
public class Student {
private String studentname;
private int rollno;
private int studentage;
public Student(int rollno, String studentname, int studentage) {
this.rollno = rollno;
this.studentname = studentname;
this.studentage = studentage;
}
...
...
public static Comparator<Student> StuNameComparator = new Comparator<Student>() {
public int compare(Student s1, Student s2) {
String StudentName1 = s1.getStudentname().toUpperCase();
String StudentName2 = s2.getStudentname().toUpperCase();
return StudentName1.compareTo(StudentName2);
}};
public static Comparator<Student> StuRollno = new Comparator<Student>() {
public int compare(Student s1, Student s2) {
int rollno1 = s1.getRollno();
int rollno2 = s2.getRollno();
return rollno1-rollno2;
}};
@Override
public String toString() {
return "[ rollno=" + rollno + ", name=" + studentname + ", age=" + studentage + "]";
}
}