List set sorting: Comparator, Collections. sort, and collections. sort

List set sorting: Comparator, Collections. sort, and collections. sort

Example

Package sortt; import java. util. arrayList; import java. util. collections; import java. util. comparator; import java. util. list; public class HomeWork {public static void main (String [] args) {List <Emp> EMS = new ArrayList <Emp> (); EMS. add (new Emp ("Terry", 25, 'M', 6000); EMS. add (new Emp ("Allen", 21, 'F', 4000); EMS. add (new Emp ("Smith", 23, 'M', 3000); System. out. println (EMS); // [(Terry, 25, m, 6000.0), (Allen, 21, f, 4000.0), (Smith, 23, m, 3000.0)] comparator <Emp> com = new Comparator <Emp> () {// anonymous internal class public int compare (Emp o1, Emp o2) {// TODO Auto-generated method stub return (int) (o1.getSalary ()-o2.getSalary () ;}}; Collections. sort (EMS, com); System. out. println (EMS); // [(Smith, 23, m, 3000.0), (Allen, 21, f, 4000.0), (Terry, 25, m, 6000.0)]}

 

 

Emp.java

class Emp{    private String name;    private int age;    private char gender;    private double salary;    public Emp(String name, int age, char gender, double salary) {        super();        this.name = name;        this.age = age;        this.gender = gender;        this.salary = salary;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public char getGender() {        return gender;    }    public void setGender(char gender) {        this.gender = gender;    }    public double getSalary() {        return salary;    }    public void setSalary(double salary) {        this.salary = salary;    }    public String toString(){        return "("+name+","+  age+"," +gender+"," + salary+")";            }        }