继承构造方法不适用

Question

我是Java新手。最近我一直在研究构造函数，继承，数组和抽象类。我试图将所有这些概念结合到代码中以供练习。

我有一个名为Person3的抽象基类，一个名为Student1的子类和一个名为Staff1的子类。我也有一个驱动程序。

我在编译时收到有关Student1和Staff1构造函数的错误，并希望得到一些解释，因为我只是没有看到问题。

有人可以请详细解释为什么发生这些错误？谢谢！

错误：

no suitable constructor found for Student1(String,Date,int,double,double) 
       Student1 st = new Student1("Jack", new Date("May", 8, 1990), 00000001, 7.50, 7.00); 
          ^
    constructor Student1.Student1(Student1) is not applicable 
     (actual and formal argument lists differ in length) 
    constructor Student1.Student1(String[],Date[],int[],double[],double[]) is not applicable 
     (actual argument String cannot be converted to String[] by method invocation conversion) 
    constructor Student1.Student1() is not applicable 
     (actual and formal argument lists differ in length) 

no suitable constructor found for Staff1(String,Date,int,double,double,double) 
       myPerson[1] = new Staff1("Will", new Date("July", 10, 1998), 00000002, 7.00, 8.00, 3900.00); 
          ^
    constructor Staff1.Staff1(Staff1) is not applicable 
     (actual and formal argument lists differ in length) 
    constructor Staff1.Staff1(String[],Date[],int[],double[],double[],double[]) is not applicable 
     (actual argument String cannot be converted to String[] by method invocation conversion) 
    constructor Staff1.Staff1() is not applicable 
     (actual and formal argument lists differ in length) 

为Student1类适用代码：

public class Staff1 extends Person3 
{ 
    private double [] salary; 

    public Staff1() 
    { 
     super(); 
     for(int i = 0; i < salary.length; i++){ 
      salary[i]=0.00; 
     } 
    } 

    public Staff1(String [] theName, Date [] theDate, int [] theSocial, double [] theWageRate, double [] theHours, double [] theSalary){ 
     super(theName, theDate, theSocial); 
     if (theSalary != null) 
      salary = theSalary; 
     else 
     { 
      System.out.println("Fatal Error: Negative salary."); 
      System.exit(0); 
     } 
    } 

    public Staff1(Staff1 originalObject){ 
     super((Person3)originalObject); 
     salary = originalObject.salary; 
    } 

驱动程序尝试下面并接收错误：：

public class Student1 extends Person3 
{ 
    private double [] wageRate; 
    private double [] hours; 

    public Student1(){ 
     super(); 
     for(int i = 0; i < wageRate.length; i++) { 
      wageRate[i] = 0.00; 
     } 
     for(int i = 0; i < hours.length; i++){ 
      hours[i] = 0.00; 
     } 
    } 

    public Student1(String [] theName, Date [] theDate, int [] theSocial, double [] theWageRate, double [] theHours){ 
     super(theName, theDate, theSocial); 
     if ((theWageRate != null) && (theHours != null)){ 
      wageRate = theWageRate; 
      hours = theHours; 
     } 
     else{ 
      System.out.println("Fatal Error: creating an illegal hourly employee."); 
      System.exit(0); 
     } 
    } 

    public Student1(Student1 originalObject) 
    { 
     super(originalObject); 
     wageRate = originalObject.wageRate; 
     hours = originalObject.hours; 
    } 

为STAFF1类适用代码

Student1 st= new Student1("Jack", new Date("May", 8, 1990), 00000001, 7.50, 7.00); 
myPerson[1] = new Staff1("Will", new Date("July", 10, 1998), 00000002, 7.00, 8.00, 3900.00); 

Answer 1

您是否知道Type[]的意思是“Array of Type”？

所以根据这两个构造函数声明：

public Student1(String [] theName, Date [] theDate, int [] theSocial, double [] theWageRate, double [] theHours) 

public Staff1(String [] theName, Date [] theDate, int [] theSocial, double [] theWageRate, double [] theHours, double [] theSalary) 

所有参数必须是数组。
但是，从您的错误消息，很明显，您传递普通值的构造函数。

从构造函数声明中删除所有[]，你应该没问题。

或者，如果参数实际上应该都是数组，你就必须调用构造函数是这样的：

Student1 st = new Student1(new String[]{"Jack"}, new Date[]{new Date("May", 8, 1990)}, new int[]{1}, new double[]{7.50}, new double[]{7.00}); 

myPerson[1] = new Staff1(new String[]{"Will"}, new Date[]{new Date("July", 10, 1998)}, new int[]{2}, new double[]{7.00}, new double[]{8.00}, new double[]{3900.00}); 

Answer 2

您的学生的构造函数：

public Student1(String [] theName, Date [] theDate, int [] theSocial, double [] theWageRate, double [] theHours) 

需要数组作为参数。但是当初始化您的学生对象时：

new Student1("Jack", new Date("May", 8, 1990), 00000001, 7.50, 7.00); 

您不使用数组，只是简单的值。您需要修改您的构造函数以获取单个值，或者您需要使用对象数组创建一个学生。

Answer 3

你的构造正在采取数组作为参数。您需要将其更改为：

public Student1(String theName, Date theDate, int theSocial, double theWageRate, double theHours) 

要了解更多有关数组，检查出https://docs.oracle.com/javase/tutorial/java/nutsandbolts/arrays.html