list集合的排序Comparator和Collections.sort，collections.sort排序

list集合的排序Comparator和Collections.sort，collections.sort排序

一個例子

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>(){ //匿名內部類                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+")";            }        }