java - 为什么 Eclipse 不会@Override？

Question

我正在阅读《Java for Dummies》一书，但遇到了问题。我不明白为什么 @Override 不起作用。我确信这与我的代码有关，因为我之前已经获得了一个多态数组来使用覆盖，但它对我来说太简单了，无法模仿。

import static java.lang.System.out;
import java.util.Scanner;
import java.io.File;
import java.io.IOException;
public class DoPayrollTypeP {



public static void main(String[] args) throws IOException {
    // TODO Auto-generated method stub

    Scanner diskScanner = new Scanner(new File("EmpInfoNew.txt"));
    Scanner kbdScanner = new Scanner (System.in);

    for(int empNum = 1; empNum<=3; empNum++){
        payOneFTEmployee (diskScanner);
    }
    for(int empNum = 4; empNum<=6; empNum++){
        payOnePTEmployee(diskScanner, kbdScanner);
    }
}
    public static void payOneFTEmployee(Scanner diskScanner){

        FullTimeEmployee ftemployee = new FullTimeEmployee();
        ftemployee.setName(diskScanner.nextLine());
        ftemployee.setJobTitle(diskScanner.nextLine());
        ftemployee.setWeeklySalary(diskScanner.nextDouble());
        ftemployee.setBenefitDeduction(diskScanner.nextDouble());
        diskScanner.nextLine();
        diskScanner.nextLine();

        ftemployee.cutCheck(ftemployee.findPaymentAmount());
        out.println();
    }

    public static void payOnePTEmployee(Scanner diskScanner, Scanner  kbdScanner) {
        PartTimeEmployee ptemployee = new PartTimeEmployee();
        ptemployee.setName(diskScanner.nextLine());
        ptemployee.setJobTitle(diskScanner.nextLine());
        ptemployee.setHourlyRate(diskScanner.nextDouble());
        diskScanner.nextLine();
        diskScanner.nextLine(); //Reads the dashed line that
        // separates two employees
        out.print("Enter ");
        out.print(ptemployee.getName());
        out.print("'s hours worked this week: ");
        int hours = kbdScanner.nextInt();
        ptemployee.cutCheck(ptemployee.findPaymentAmount(hours));
        out.println();
        }
}       

下一个类:

import static java.lang.System.out;

public class Employee {
    private String name;
    private String jobTitle;



    public void setName(String nameIn) {
        name = nameIn;
    }
    public String getName() {
        return name;
    }
    public void setJobTitle(String jobTitleIn) {
        jobTitle = jobTitleIn;
    }
    public String getJobTitle() {
        return jobTitle;
    }

    public void cutCheck(double amountPaid){
        out.printf("Pay to the order of %s", name);
        out.printf("(%s) ***$", jobTitle);
        out.printf("%,.2f\n", amountPaid);

    }


}

下一个类:

public class PartTimeEmployee extends Employee{

private double hourlyRate;

public void setHourlyRate(double hourlyRateIn) {
    hourlyRate = hourlyRateIn;
}
public double getHourlyRate() {
    return hourlyRate;
}

public double findPaymentAmount(int hours){
    return hourlyRate * hours;
    } //method that should be overriden
}

应该覆盖的类:

public class PartTimeWithOver extends PartTimeEmployee{

@Override
public double findPaymentAmount(int hours) {
if(hours <= 40) {
return getHourlyRate() * hours;
} else {
return getHourlyRate() * 40 +
getHourlyRate() * 2 * (hours - 40);
}
}

}

EmpInfoNew.(txt) 文件

乔什莫CEO5000.00

500.00

艾德·什莫队长5000.00

500.00

鲍勃·什莫名誉执行官1000.00

200.00

戴夫·什莫司机

7.25

埃德布拉拉做饭

8.50

伦什莫厨房主管

12.50

Answer 1

您已将对象实例化为

PartTimeEmployee ptemployee = new PartTimeEmployee();

这是一个base类PartTimeWithOther所以它不能调用overridden derived中的方法类。

更改为

PartTimeEmployee ptemployee = new PartTimeWithOver();

Here是一个很好的教程，带有图表，解释了多态性