为什么我的数组比较排序不起作用？ [复制]答案

【问题标题】：Why my comparating sort from a array doesn't work? [duplicate]为什么我的数组比较排序不起作用？ [复制]
【发布时间】：2021-11-10 00:24:34
【问题描述】：

主类：

package simulator;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;



import rh.Employee;
import rh.SalaryIncrease;
import rh.SalaryIncreaseMock;
import rh.increase.GradualSalaryIncrease;
import rh.increase.StandardSalaryIncrease;

public class Simulator {

    public static void main(String[] args) {
        new Simulator();
    }
    
    private List<Employee> ListOfEmployees;
    
    public Simulator() {
        System.out.println("STRATEGY PATTERN et POLYMORPHISME ******************************");
        this.seedData();
        this.printData("Employés avant les augmentations");
        this.applySalaryIncrease();
        this.printData("Employés après les augmentations");
    }


    private void seedData() {
        this.ListOfEmployees = new ArrayList<Employee>();
        
        this.ListOfEmployees.add(new Employee("Jean", 50000));
        this.ListOfEmployees.add(new Employee("Françis", 50000));
        this.ListOfEmployees.add(new Employee("Jeanne", 10000));
        this.ListOfEmployees.add(new Employee("Kevin", 85000));
        this.ListOfEmployees.add(new Employee("Bernard", 10000));
        this.ListOfEmployees.add(new Employee("James", 35000));
        Collections.sort(this.ListOfEmployees, new EmployeeSortByAnnualSalaryComparator());
        
        
        this.printData("Employés classée en ordre alphabétique");
        
        this.printData("Employés classée en ordre croisant de salaire");
    }
    

     
    private void applySalaryIncrease() {
        int counter = 0;
        for(Employee anEmployee:this.ListOfEmployees) {
            SalaryIncrease increase;
            
            if(counter % 2 == 0) {
                increase = new StandardSalaryIncrease(10);
            }
            else {
                increase = new GradualSalaryIncrease(10);
            }
            
            anEmployee.applySalaryIncrease(increase);
            counter++;
        }
    }
    
    private void printData(String title) {
        System.out.println();
        System.out.println(title);
        System.out.println("=======================================================");
        for(Employee anEmployee:this.ListOfEmployees) {
            System.out.println(anEmployee.toString());
            
        }
        
    }
}

我的比较器界面

package simulator;

public interface Comparator<T> {
    int compare(T firstElement,T secondElement);
}

比较器实现

package simulator;

import rh.Employee;

public class EmployeeSortByAnnualSalaryComparator implements Comparator<Employee>{

    public EmployeeSortByAnnualSalaryComparator(){
        
    }
    @Override
    public int compare(Employee anEmployeeSalary, Employee aSecondEmployeeSalary) {
        if(anEmployeeSalary.getSalary() < aSecondEmployeeSalary.getSalary()) {
            return -1;
        }
        if(anEmployeeSalary.getSalary() == aSecondEmployeeSalary.getSalary()) {
            return 0;
        }
        else {
            return 1;
        
        }
    }

}

界面应该和t一样。

当我尝试对名称或数字进行排序时，我在排序时看到此错误，表明我的类型错误： The method sort(List<T>, >Comparator<? super T>) in the type Collections is not applicable for the arguments>(List<Employee>, EmployeeSortByAnnual Salary Comparator).

我做错了吗？

【问题讨论】：

请以可复制粘贴的方式粘贴分隔的类进行测试。
Collections.sort(this.ListOfEmployees, Comparator.comparing(Employee::getSalary));
友情反馈：下次能否指出错误信息属于哪一步。在这种情况下，这是一个编译错误。这将有助于了解触发错误的问题类型。

标签： java eclipse sorting comparator junit5

【解决方案1】：

您的EmployeeSortByAnnualSalaryComparator 类正在实现您自己的simulator.Comparator 接口，但它应该实现java.util.Comparator 接口。

Collections.sort 方法需要一个实现java.util.Comparator 接口的比较器。

【讨论】：

非常感谢。