java - 如何从驱动程序访问复制构造函数

Question

我有一个司机充当我的测试员。

这是驱动程序:

public class CustomerTest {

    private static int customerCounter = 0;

    public static boolean test1(){
        System.out.println("Test1: create a customer");
        Customer c = new Customer("Alice", "Smith");
        customerCounter++;
        return c.getName().equals("Alice Smith") && customerCounter == c.getCustomerID();
    }

    public static boolean test2() {
        System.out.println("Test2: create two customers");
        Customer c1 = new Customer("Alice", "Smith");
        Customer c2 = new Customer("Bob", "Simpson");
        customerCounter += 2;
        return c1.getName().equals("Alice Smith") && (customerCounter - 1) == c1.getCustomerID()
            && c2.getName().equals("Bob Simpson") && (customerCounter) == c2.getCustomerID();
    }

    public static boolean test4() {
        System.out.println("Test4: copy a customer");
        Customer c1 = new Customer("Alice", "Smith");
        Customer c2 = new Customer("Bob", "Simpson");
        c1.copy(c2);
        customerCounter += 2;
        return c1.getName().equals("Bob Simpson") && (customerCounter) == c1.getCustomerID()
            && c2.getName().equals("Bob Simpson") && (customerCounter) == c2.getCustomerID()
            && c1 != c2;
    }
    public static void main(String[] args) {
        String result = "";
        //System.out.print("Test 1: ");
        result = test1() ? "pass." : "failed.";
        System.out.println(result);

        //System.out.print("Test 2: ");
        result = test2() ? "pass." : "failed.";
        System.out.println(result);

        //System.out.print("Test 4: ");
        result = test4() ? "pass." : "failed.";
        System.out.println(result);

这是我到目前为止编写的代码:

public class Customer {

    public static final int MAX_ACCOUNTS = 5;

    private String firstName;
    private String lastName;
    private int customerID;
    private BankAccount[] accounts;
    private int numAccounts;
    private static int nextCustomerID = 1;

    //default constructor
    public Customer() {
        firstName = "";
        lastName = "";
        customerID = nextCustomerID;
        accounts = null;
        numAccounts = 0;
        nextCustomerID++;

    }

    //Constructor sets name and initialized values
    //@param first is the first name
    //@param last is the last name
    public Customer (String first, String last)
    {
        this.firstName = first;
        this.lastName = last;
        this.customerID = nextCustomerID;
        nextCustomerID++;



    }    

    public void copy (Customer copyFrom)
    {
        Customer aCustomer = new Customer();
        aCustomer.firstName = copyFrom.firstName;
        aCustomer.lastName = copyFrom.lastName;
        aCustomer.customerID = copyFrom.customerID;
        aCustomer.accounts = copyFrom.accounts;
        aCustomer.numAccounts = copyFrom.numAccounts;
    }
}

我的复制构造函数未通过驱动程序测试 4。我不确定为什么，因为我复制了方法中调用的所有内容。

Answer 1

如我所见，copy() 在您的情况下不是构造函数，它只是先前创建的对象的一种方法。如果你想创建对象然后从另一个对象填充它你需要写这样的东西:

public void copy (Customer copyFrom) {
        this.firstName = copyFrom.firstName;
        this.lastName = copyFrom.lastName;
        this.customerID = copyFrom.customerID;
        this.accounts = copyFrom.accounts;
        this.numAccounts = copyFrom.numAccounts;
    }