如何创建一个使用另一个类的变量的 java 对象？

Question

如何创建一个使用另一个类的变量或调用整个构造函数的 java 对象？比如accountNumber, firstName, lastName, phone都是传入address的变量，由street, city, state, zip组成，已经创建好了：Address address = new Address(street, city, state, zip);数据仅由兆字节组成，并且已经创建：Data data = new Data(megabytes);这就是我对客户对象的看法：Customer customer = new Customer(accountNumber, firstName, lastName, address, phone, data);这应该是一个“重载的构造函数”，但我不明白那是什么意思。这是我到目前为止的构造函数：public Customer(String accountNumber, String firstName, String lastName, Address address, int phone, Data megabytes){    this.accountNumber = accountNumber;    this.firstName = firstName;     this.lastName = lastName;    this.address = address;     this.phone = phone;     this.megabytes= megabytes; }我收到错误：The constructor Customer(String, String, String, Address, int, Data) is undefined

Answer 1

乍一看，一切似乎都很好。我希望你在编译之前保存了文件。

既然你提到你不明白什么是重载构造函数，我会尽力解释一下。

重载的构造函数具有相同的构造函数名称，但它在以下方面与其他构造函数不同 -

1. 它有不同数量的正式参数

2. 构造函数形参类型顺序不同

这是一个例子 -

public class Customer {

    private String firstName;

    private String lastName;

    private int phoneNumber;

    public Customer() {

        // default constructor

    }

    public Customer(String firstName) {

        this.firstName = firstName;

    }

    public Customer(String firstName, String lastName) {

        this.firstName = firstName;

        this.lastName = lastName;

    }

    public Customer(String firstName, String lastName, int phoneNumber) {

        this.firstName = firstName;

        this.lastName = lastName;

        this.phoneNumber = phoneNumber;

    }

    public Customer(int phoneNumber, String firstName, String lastName) {

        this.phoneNumber = phoneNumber;  

        this.firstName = firstName;

        this.lastName = lastName;

    }

// This is not an overloaded constructor as there is already a constructor of type

// Customer(String, String)

//    public Customer(String lastName, String firstName) {

//        this.lastName = lastName;

//        this.firstName = firstName;

//    }

}