Как отсортировать определенные элементы в ArrayList в Java?

Question

Как отсортировать определенные элементы в ArrayList в Java?

1

Я знаю, что этот вопрос задан. Но я считаю, что мой вопрос - это особый случай. Я до сих пор не смог понять это.

Итак, мне нужно сортировать объекты сотрудников по их возрасту, если они находятся в отделах информационных систем или учетной записи.

Тем не менее, я не могу заставить код просто сортировать Employee в отделах Information Systems или Accoutning, как бы я указал, просто сортировать их по возрасту и просто распечатывать остальные?.

Вот весь соответствующий код:

Класс сотрудника:

public class Employee {

private String name;
private int age;
private String department;

public String getDept(){
    return department;
}//end dept

public void setDept(String dept){
    this.department = dept;
}//end

public String getName(){
    return name;
}//end name

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

public int getAge(){
    return age;
}//end age

public void setAge(int a){
    this.age = a;
}//end



  public String toString(){

      return name + " " + age + " " + department;
  }//end to string


public Employee (String n,int age,String dept){

    this.name = n;
    this.age = age;
    this.department = dept;

}//end employee
}//end class

Класс отдела:

import java.util.*;






public class Department implements Comparator<Employee>  {

@Override
public int compare(Employee o1, Employee o2){

    return  o1.getAge() - o2.getAge();

}//end method

 }//end departmen

Основной класс методов:

import java.util.*;



public class Company  {


public static void main(String [] args){


    PrimeAgeChecker p = new PrimeAgeChecker();
    ArrayList<Employee> test = new ArrayList<Employee>();


    test.add(new Employee("Counting Guru",55,"Accounting"));
    test.add(new Employee("Counting Pro",45,"Accounting"));
    test.add(new Employee("Counting Savvy",40,"Accounting"));
    test.add(new Employee("Counting Novice",25,"Accounting"));
    test.add(new Employee("Sales Guru",50,"Marketing"));
    test.add(new Employee("Sales Pro",48,"Marketing"));
    test.add(new Employee("Sales Savvy",38,"Marketing"));
    test.add(new Employee("Hiring Guru",58,"Human Resrouces"));
    test.add(new Employee("Hiring Pro",47,"Human Resrouces"));
    test.add(new Employee("Hacking Pro",47,"Information Systems"));
    test.add(new Employee("Hacking Guru",51,"Information Systems"));
    test.add(new Employee("Hacking Savvy",38,"Information Systems"));
    test.add(new Employee("Hacking Novice",23,"Information Systems"));


    for(Employee i: test){
    if(i.getDept().equals("Information Systems") ||      i.getDept().equals("Accounting")){
        Collections.sort(test, new Department());
        System.out.println(i + " " + p.isPrime(i));
    }//end 
      else{
          System.out.println(i + " " + p.isPrime(i));
      }





}//end main
}//end company

MrTimotheos 18 март 2014, в 22:24

Источник

Теги:

java

list

sorting

2 ответа

Ещё вопросы

Pinkesh Sharma · Answer 1 · 2014-03-19T08-34-00.000Z

Add this to Your Model 

@Override
    public int compareTo(Object arg0) {
        // TODO Auto-generated method stub
        Employee employee = (Employee) arg0;
        if(employee.getAge() == 10 && this.getAge() == 10 ){

            return this.getDepartment().compareTo(employee.getDepartment());
        } 
        return 0;
    }

но это будет работать только в том случае, если все записи, которые вы хотите отсортировать, вместе. И, пожалуйста, измените поля, по которым вы хотите, чтобы они были отсортированы.

Patrick · Answer 2 · 2014-03-19T04-50-00.000Z

попробуйте этот пример, я покинул PrimeAgeCheck:

package de.professional_webworkx.blog.companymanager;

    import de.professional_webworkx.blog.companymanager.comparators.AgeComparator;
    import de.professional_webworkx.blog.companymanager.filter.DepartmentFilter;
    import de.professional_webworkx.blog.companymanager.filter.utils.FilterUtils;
    import de.professional_webworkx.blog.companymanager.model.Employee;
    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.List;

    public class CompanyManager {

        public static void main(String[] args) {
            List<Employee> employees = new ArrayList<>();

            employees.add(new Employee("Counting Guru", 55, "Accounting"));
            employees.add(new Employee("Counting Pro", 45, "Accounting"));
            employees.add(new Employee("Counting Savvy", 40, "Accounting"));
            employees.add(new Employee("Counting Novice", 25, "Accounting"));
            employees.add(new Employee("Sales Guru", 50, "Marketing"));
            employees.add(new Employee("Sales Pro", 48, "Marketing"));
            employees.add(new Employee("Sales Savvy", 38, "Marketing"));
            employees.add(new Employee("Hiring Guru", 58, "Human Resrouces"));
            employees.add(new Employee("Hiring Pro", 47, "Human Resrouces"));
            employees.add(new Employee("Hacking Pro", 47, "Information Systems"));
            employees.add(new Employee("Hacking Guru", 51, "Information Systems"));
            employees.add(new Employee("Hacking Savvy", 38, "Information Systems"));
            employees.add(new Employee("Hacking Novice", 23, "Information Systems"));

            for(Employee employee : employees) {
                System.out.println(employee);
            }

            List<String> filterDepartsments = new ArrayList<>();
            filterDepartsments.add("Accounting");
            filterDepartsments.add("Information Systems");

            List<Employee> applyFilter = FilterUtils.applyFilter(employees, new DepartmentFilter("Accounting", "Information Systems"));

            System.out.println("filtered list");
            for(Employee employee : applyFilter) {
                System.out.println(employee);
            }

            Collections.sort(applyFilter, new AgeComparator());
            System.out.println("sorted list");
            for(Employee employee : applyFilter) {
                System.out.println(employee);
            }
        }

    }

Наемный рабочий

package de.professional_webworkx.blog.companymanager.model;


public class Employee {

    private String name;
    private int age;
    private String department;

    public Employee(final String name, final int age, final String department) {
        this.name       = name;
        this.age        = age;
        this.department = department;
    }

    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 String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }


    @Override
    public String toString() {
        return name + ", " + age + ", " + department;
    }

}

Интерфейс IFilter

package de.professional_webworkx.blog.companymanager.filter;

public interface IFilter<T> {

    public boolean accept(T value);
}

простой Департаментфильтр

package de.professional_webworkx.blog.companymanager.filter;

import java.util.ArrayList;
import java.util.List;

public class DepartmentFilter<String> implements IFilter<String>{

    private final String acceptedDepartment;
    private final String acceptedDepartment2;

    public DepartmentFilter(final String department, final String department2) {
        this.acceptedDepartment = department;
        this.acceptedDepartment2= department2;
    }
    @Override
    public boolean accept(String value) {
        return acceptedDepartment.equals(value) || acceptedDepartment2.equals(value);
    }

}

AgeComparator

package de.professional_webworkx.blog.companymanager.comparators;

import de.professional_webworkx.blog.companymanager.model.Employee;
import java.util.Comparator;

public class AgeComparator implements Comparator<Employee>{

    @Override
    public int compare(Employee o1, Employee o2) {

        return Integer.valueOf(o1.getAge()).compareTo(Integer.valueOf(o2.getAge()));
    }

}

Класс FilterUtils

package de.professional_webworkx.blog.companymanager.filter.utils;

import de.professional_webworkx.blog.companymanager.filter.IFilter;
import de.professional_webworkx.blog.companymanager.model.Employee;
import java.util.ArrayList;
import java.util.List;

public class FilterUtils {

    private static final List<Employee> filteredList = new ArrayList<>();

    public static List<Employee> applyFilter(final List<Employee> list, final IFilter filter) {

        for(Employee e : list) {
            if(filter.accept(e.getDepartment())) {
                filteredList.add(e);
            }
        }

        return filteredList;
    }
}

Образец вывода

Counting Guru, 55, Accounting
Counting Pro, 45, Accounting
Counting Savvy, 40, Accounting
Counting Novice, 25, Accounting
Sales Guru, 50, Marketing
Sales Pro, 48, Marketing
Sales Savvy, 38, Marketing
Hiring Guru, 58, Human Resrouces
Hiring Pro, 47, Human Resrouces
Hacking Pro, 47, Information Systems
Hacking Guru, 51, Information Systems
Hacking Savvy, 38, Information Systems
Hacking Novice, 23, Information Systems
filtered list
Counting Guru, 55, Accounting
Counting Pro, 45, Accounting
Counting Savvy, 40, Accounting
Counting Novice, 25, Accounting
Hacking Pro, 47, Information Systems
Hacking Guru, 51, Information Systems
Hacking Savvy, 38, Information Systems
Hacking Novice, 23, Information Systems
sorted list
Hacking Novice, 23, Information Systems
Counting Novice, 25, Accounting
Hacking Savvy, 38, Information Systems
Counting Savvy, 40, Accounting
Counting Pro, 45, Accounting
Hacking Pro, 47, Information Systems
Hacking Guru, 51, Information Systems
Counting Guru, 55, Accounting

Возможно, это поможет вам. Патрик