实现继承重写toString方法

Question

我创建了一个（人，学生，员工，教师和职员）类。 人必须将学生和雇员分类。 雇员有两个子类：教职员工。 我已经完成了所有编码，并且它们工作正常，但我的驱动程序类 TestPerson程序却给出了编译错误。

注意：一个测试程序，该程序创建Person，Student，Employee，Faculty，Staff，并调用其toString方法。

驱动程序类TestPerson.java的错误如下：-

error: constructor Student in class Student cannot be applied to given types;
error: no suitable constructor found for Employee(String,String,String,String)
error: constructor Faculty in class Faculty cannot be applied to given types;
error: no suitable constructor found for Staff(String,String,String,String)"

**我只是提供驱动程序类的代码。 如果您需要其他类别的其他编码，请在评论中注明，我会立即发布。

请在下面查看我的代码：

public class TestPerson {

    public static void main(String[] args) {
        Person person = new Person("John Doe", "123 Somewhere", "415-555-1212", "johndoe@somewhere.com");
        Person student = new Student("Mary Jane", "555 School Street", "650-555-1212", "mj@abc.com", "junior");
        Person employee = new Employee("Tom Jones", "777 B Street", "40-88-889-999", "tj@xyz.com");
        Person faculty = new Faculty("Jill Johnson", "999 Park Ave", "92-52-22-3-333", "jj@abcxyz.com");
        Person staff = new Staff("Jack Box", "21 Jump Street", "707-21-2112", "jib@jack.com");

        System.out.println(person.toString() + "\n");
        System.out.println(student.toString() + "\n");
        System.out.println(employee.toString() + "\n");
        System.out.println(faculty.toString() + "\n");
        System.out.println(staff.toString() + "\n");
        }
}

//人员班

public class Person {

    private String name;
    private String address;
    private String phone_number;
    private String email_address;

    public Person() {
    }

    public Person(String newName, String newAddress, String newPhone_number, String newEmail){
        name = newName;
        address = newAddress;
        phone_number = newPhone_number;
        email_address = newEmail;
    }

    public void setName(String newName){
        name = newName;
    }

    public String getName(){
        return name;
    }

    public void setAddress(String newAddress){
        address = newAddress;
    }

    public String getAddress(){
        return address;
    }

    public void setPhone(String newPhone_number){
        phone_number = newPhone_number;
    }

    public String getPhone(){
        return phone_number;
    }

    public void setEmail(String newEmail){
        email_address = newEmail;
    }

    public String getEmail(){
        return email_address;
    }

    public String toString(){
        return "Name :"+getName();
    }

}

//学生班

public class Student extends Person {

    public final String class_status;

    public Student(String name, String address, int phone, String email, String classStatus) {
    super(name, address, phone, email);
    class_status = classStatus;
    }
    public String toString(){
        return "Student Status: " + super.getName();
    }

}

//员工分类

import java.util.Date;
public class Employee extends Person{

    private String office;
    private double salary;
    private Date hire;

    public Employee() {
    }

    public Employee(String name, String address, int phone, String email){
        super(name, address, phone, email);
    }

    public Employee(String office, double salary, Date hire){
        this.office = office;
        this.salary = salary;
        this.hire = hire;
    }

    public void setOffice(String office){
        this.office = office;
    }

    public String getOffice(){
        return this.office;
    }

    public void setSalary(double salary){
        this.salary = salary;
    }

    public double getSalary(){
        return this.salary;
    }

    public void setHire(Date hire){
        this.hire = hire;
    }

    public Date getHire(){
        return this.hire;
    }

    public String toString(){
        return "Office " + super.getName();
    }
}

//教师班

public class Faculty extends Employee {
    private String officeHours;
    private int rank;

    public Faculty(String name, String address, int phone, String email) {
    super(name, address, phone, email);
    }

    public String toString(){
        return "Office " + super.getOffice();
    }
}

//职员班

public class Staff extends Employee {
    private String title;

    public Staff(String name, String address, int phone, String email) {
    super(name, address, phone, email);
    }

    public Staff(String title){
        this.title = title;
    }

    public void setTitle(String title){
        this.title = title;
    }
    public String getTitle(){
        return this.title;
    }

    public String toString(){
        return "Title :" + super.getName();
    }
}

Answer 1

出现这些错误的原因是，构造函数不存在。

错误：班级Student中的构造函数Student无法应用于给定类型； 错误：找不到适用于Employee（String，String，String，String）的合适的构造函数

这意味着您只有具备以下条件，才能编译代码：

Student(String name, String addr, String phone, String email) {
    ....
}

假设您已在构造函数中设置了属性，则toString如下所示：

public String toString() {
    return this.name + "\n" + this.addr + "\n" + this.phone + "\n" + this.email;

}

更新

您的问题是Student仅具有以下构造函数：

public Student(String name, String address, int phone, String email, String classStatus)

学生需要一个仅包含四个字符串作为其参数的构造函数。 或者，您可以使所有内容都使用您指定的五个参数。

Answer 2

它可能与问题本身无关，但我认为可以像这样完善设计：

• 用角色名称定义抽象类角色
• 定义班级学生，员工，员工继承角色
• 定义类Person具有所有人员类型，姓名等的公共属性，并且内部具有Role类型的属性

然后在Person和所有Role实现中定义toString

这样，您将能够独立于角色来扩展或修改人员，从而使设计更加灵活

Answer 3

Person的构造函数需要String作为第三个参数，但是您试图将int phone传递给子类中的超级构造函数。 那是行不通的，因为它是错误的类型。

顺便说一句：您应该始终用字符串而不是整数来表示电话号码。

1. 添加或减去电话号码没有任何意义。
2. 整数不允许前导零，这在某些国家/地区用于区域代码。
3. 整数不能大于2147483648。当您尝试存储非常长的电话号码时，此看似任意的限制将导致非常意外的错误。

Answer 4

首先在所有类中将“电话号码”数据类型设置为整数。

主要功能将是：

public class TestPerson {
    public static void main(String[] args) {
        Person person = new Person("John Doe", "123 Somewhere", "415-555-1212",
                                   "johndoe@somewhere.com");
        Person student = new Student("Mary Jane", "555 School Street", 
                                     650-555-1212, "mj@abc.com", "junior");
        Person employee = new Employee("Tom Jones", "777 B Street", 
                                       40-88-889-999,  "tj@xyz.com");
        Person faculty = new Faculty("Jill Johnson", "999 Park Ave",
                                     92-52-22-3-333, "jj@abcxyz.com");
        Person staff = new Staff("Jack Box", "21 Jump Street", 707-21-2112, 
                                 "jib@jack.com");

        System.out.println(person.toString() + "\n");
        System.out.println(student.toString() + "\n");
        System.out.println(employee.toString() + "\n");
        System.out.println(faculty.toString() + "\n");
        System.out.println(staff.toString() + "\n");
    }
}