构造函数 Teacher(Teacher) 未定义

Question

我在一个名为 'Department' 的 class 中使用复制构造函数和继承来调用来自 class 'Teacher' 的信息，这是一个子 class 'Person'。创建 set/get 方法后，出现上述错误。任何人都知道为什么会发生这种情况？

代码来自 'Department' class:

public class Department {
private String deptName;
private int numMajors;
private Teacher[] listTeachers; //inherits from Person class
private Student[] listStudents; //inherits from Person class

    // First constructor for Department
    public Department(String dn, int nm, Teacher[] listTeachers, Student[] listStudents) {
    this.deptName = dn;
    this.numMajors = nm;

    this.listTeachers = new Teacher[listTeachers.length];
    for (int i = 0; i < this.listTeachers.length; i++)
    {
        this.listTeachers[i] = new Teacher (listTeachers[i]);
    }

    //set method for Teachers Array
    public void setListTeachers (Teacher[] other) {
    this.listTeachers = new Teacher[other.length];
    for (int i = 0; i < listTeachers.length; i++) {
        this.listTeachers[i] = new Teacher (other[i]);
    }
}

    //get method for Teachers Array
    public Teacher[] getListTeachers() {
    Teacher[] copyTeachers = new Teacher[listTeachers.length];
    for (int i = 0; i < copyTeachers.length; i++) {
        copyTeachers[i] = new Teacher(this.listTeachers[i]);
    }
    return copyTeachers;
}

以下是给我错误的行：

1) this.listTeachers[i] = new Teacher (listTeachers[i]);

2) this.listTeachers[i] = new Teacher (other[i]);

3) copyTeachers[i] = new Teacher(this.listTeachers[i]);

代码来自 'Teacher' class:

public class Teacher extends Person {
private String id;
private int salary;
private int num_yr_prof;

//Constructor for use in Teacher main method.
public Teacher(String n, int a, String s, boolean al, String i, int sal, int numyr) {
    super(n, a, s, al);
    this.id = i;
    this.salary = sal;
    this.num_yr_prof = numyr;
}

//Copy constructor for use in Department class.
public Teacher (String n, int a, String s, boolean al, Teacher other) {
    super(n, a, s, al);
    if (other == null) {
        System.out.println("Fatal Error!");
        System.exit(0);
    }

    this.id = other.id;
    this.salary = other.salary;
    this.num_yr_prof = other.num_yr_prof;
}

Answer 1

你需要给你的 Teacher class 一个接受 Teacher 的构造函数：

public Teacher(Teacher teacher) {
// do something
}

Answer 2

您的复制构造函数可能如下所示：

    public Teacher(Teacher teacher) {
        this( teacher.n, teacher.a, teacher.s, teacher.al, 
              teacher.id, teacher.salary, teacher.num_yr_prof );
    }

由于您没有显示 Person class 的代码，我在这里使用了变量名称 n、a、s 和 al。它们应该被 Person class 中命名的任何变量替换。当然，这假设这些变量是 public 或受保护的。如果它们是私有的，则需要为这些变量使用 getter（即使它们是 public 或受保护的也是首选）。

构造函数 Teacher(Teacher) 未定义

The constructor Teacher(Teacher) is undefined

java

inheritance

composition

代码来自 'Department' class:

代码来自 'Teacher' class: