Comparable compareTo

[这个昵称有点帅]

package list;

import java.util.*;

public class EmployeeSortTest {
	public static void main(String[] args) {
		Employee[] staff = new Employee[3];
		staff[0] = new Employee("Tom", 3500);
		staff[1] = new Employee("Jack", 2500);
		staff[2] = new Employee("Rose", 5600);
		
		Arrays.sort(staff);
		
		for (Employee e:staff) {
			System.out.println("Name = " + e.getName() + " Salary = " + e.getSalary());
		}
		
		Manager[] managers = new Manager[4];
		managers[0] = new Manager("Lucy", 3500, 1000);
		managers[1] = new Manager("Keith", 4000, 2000);
		managers[2] = new Manager("Jennifer", 5600, 500);
		managers[3] = new Manager("Tony", 5000, 1500);
		// 这里想实现按照bonus排序
		Arrays.sort(managers);
		
		for (Manager m:managers) {
			System.out.println("Name = " + m.getName() + " Salary = " + m.getSalary() + " Bonus = " + m.getBonus());
		}
	}
}

class Manager extends Employee {
	private double bonus;
	
	public Manager(String n, double s, double b) {
		super(n, s);
		bonus = b;
	}

	public double getBonus() {
		return bonus;
	}
	// 直接在这里写，不起作用，知道是错的，不知道该咋写
	public int compareTo(Manager ma) {
		if (bonus < ma.bonus) return -1;
		if (bonus > ma.bonus) return 1;
		return 0;
	}
}

class Employee implements Comparable<Employee> {
	private String name;
	private double salary;
	
	public Employee(String n, double s) {
		name = n;
		salary = s;
	}

	public String getName() {
		return name;
	}
	
	public double getSalary() {
		return salary;
	}
	
	public void raiseSalary(double byPercent) {
		double raise = salary * byPercent / 100;
		salary += raise;
	}
	@Override
	public int compareTo(Employee em) {
		if (salary < em.salary) return -1;
		if (salary > em.salary) return 1;
		return 0;
	}
	
}

想实现manager的bonus排序，怎么弄？

[花木兰1闪21A]

是不是父类中的ComparaTo没有被继承，你manager再实现那接口试试

[zxd297139205]

你子类中的compareTo方法不是重写父类的方法（参数类型不同），子类中可以这么写

	    @Override
	    public int compareTo(Employee ma) {
	    	Manager m=(Manager)ma;
	        if (bonus < m.bonus) return -1;
	        if (bonus > m.bonus) return 1;
	        return 0;
	    }

[达达KZT]

[花木兰1闪21A]

嗯，是地，楼上是正解，加@Override

[这个昵称有点帅]

引用 1 楼 tlfu_12344 的回复:

是不是父类中的ComparaTo没有被继承，你manager再实现那接口试试

如果加上 implements Comparable<Employee>，也不行，因为Employee中没有bonus, 如果用implements Comparable<Manager>，会报错： The interface Comparable cannot be implemented more than once with different arguments: Comparable<Employee> and Comparable<Manager> 不能有两个不同的参数

[这个昵称有点帅]

引用 2 楼 zxd297139205 的回复:

你子类中的compareTo方法不是重写父类的方法（参数类型不同），子类中可以这么写 Java code ? 12345678 @Override public int compareTo(Employee ma) { Manager m=(Manager)ma; if (bonus < m.bonus) return ……

谢谢 Manager m=(Manager)ma;