Question

我只是想了解一些事情。 testClass（z1）对象有什么意义？

我理解的方式是，它是所有其他物体的起点。我真的在问这意味着什么，为什么/如何测试一个testClass需要一个自我的实例？还有另一种方法可以达到相同的效果吗？

以下代码： -

public class testBank {  

creditAccount a1 = new creditAccount("Mary Chapple", 2400.41);
creditAccount a2 = new creditAccount("Jim Smith", 2.56);
creditAccount a3 = new creditAccount("Henry A Jones", 700.89);
currentAccount b1 = new currentAccount("Simon Hopkins", 86.01);
currentAccount b2 = new currentAccount("Jack C Whitheridge", 40000.29);
currentAccount b3 = new currentAccount("Bill Sutton", 100.23);
depositAccount c1 = new depositAccount("Theo Gibson", 145.99);
depositAccount c2 = new depositAccount("Jasper Williams", 3000.29);          
depositAccount c3 = new depositAccount("Julie Banks", 1000001.99);      
savingsAccount d1 = new savingsAccount("Burnard White", 2400.42);
savingsAccount d2 = new savingsAccount("Richard Bennett", 203.16);
savingsAccount d3 = new savingsAccount("Bob Robinson", 10000.11);





public testBank()
        //Create an array of objects.//
{
    bankAccount[]theAccounts = {a1,a2,a3,b1,b2,b3,c1,c2,c3,d1,d2,d3};

    showAccounts (theAccounts);
}
private void showAccounts(bankAccount[] aa)
{ 
    for (int i = 0;i <aa.length;i++)  
    {


        System.out.println("Account Holder: " +aa[i].getAccountName());
         System.out.println("Balance = £" +aa[i].getBalance());
     System.out.println("Balance pluss APR = £" +aa[i].calculateInterest());


    }
}

public static void main(String[]args)
{

    testBank z1 = new testBank();
}

感谢您的帮助。

Answer 1

testClass的要点是通过在标准输出上打印类bankAccount的参数和方法结果来测试您的帐户：

您的类creditAccount，currentAccount，depositAccount和savingsAccount扩展了类bankAccount（这些类继承了类bankAccount）。

如果您不想使用testBank类，您还可以在bankAccount类中创建一个打印这些信息的方法打印

public void print ()
{ 
    System.out.println("Account Holder: " + this.getAccountName());
    System.out.println("Balance = £" + this.getBalance());
    System.out.println("Balance pluss APR = £" + this.calculateInterest());
}

然后您将使用以下方式测试您的帐户：

public static void main(String[]args)
{
    creditAccount a1 = new creditAccount("Mary Chapple", 2400.41);
    currentAccount b1 = new currentAccount("Simon Hopkins", 86.01);
    depositAccount c1 = new depositAccount("Theo Gibson", 145.99);    
    savingsAccount d1 = new savingsAccount("Burnard White", 2400.42);
    a1.print();
    b1.print();
    c1.print();
    d1.print();
}

Answer 2

测试类实际上并不需要自己的实例，它通常需要的是您正在测试的任何类的实例。通常，您将从不同的文件和测试文件中测试一个类，并测试正在测试的调用类的实例。

Answer 3

testBank（）方法是一个构造函数。创建新的testBank实例时会调用此函数。

您应该使用此方法初始化不同的变量（a1，a2等...）。

public class testBank
{  
    private creditAccount a1;
    private creditAccount a2;
    private creditAccount a3;
    private currentAccount b1;
    private currentAccount b2;
    private currentAccount b3;
    private depositAccount c1;
    private depositAccount c2;          
    private depositAccount c3;      
    private savingsAccount d1;
    private savingsAccount d2;
    private savingsAccount d3;

    public testBank()
        //Create an array of objects.//
    {
        this.a1 = new creditAccount("Mary Chapple", 2400.41);
        this.a2 = new creditAccount("Jim Smith", 2.56);
        this.a3 = new creditAccount("Henry A Jones", 700.89);
        this.b1 = new currentAccount("Simon Hopkins", 86.01);
        this.b2 = new currentAccount("Jack C Whitheridge", 40000.29);
        this.b3 = new currentAccount("Bill Sutton", 100.23);
        this.c1 = new depositAccount("Theo Gibson", 145.99);
        this.c2 = new depositAccount("Jasper Williams", 3000.29);          
        this.c3 = new depositAccount("Julie Banks", 1000001.99);      
        this.d1 = new savingsAccount("Burnard White", 2400.42);
        this.d2 = new savingsAccount("Richard Bennett", 203.16);
        this.d3 = new savingsAccount("Bob Robinson", 10000.11);
        bankAccount[]theAccounts = {a1,a2,a3,b1,b2,b3,c1,c2,c3,d1,d2,d3};

        showAccounts (theAccounts);
    }

    private void showAccounts(bankAccount[] aa)
    { 
        for (int i = 0;i <aa.length;i++)  
        {
         System.out.println("Account Holder: " +aa[i].getAccountName());
         System.out.println("Balance = £" +aa[i].getBalance());
         System.out.println("Balance pluss APR = £" +aa[i].calculateInterest());
        }
    }

    public static void main(String[]args)
    {

        testBank z1 = new testBank();
    }
}

那么，那里发生了什么？

当您致电testBank z1 = new testBank();时，您正在创建testBank类的新实例。因此，调用默认构造函数（testBank（）函数）。在默认构造函数中，初始化所有私有变量，然后构造一个数组，最后调用showAccounts方法（此方法打印数组内容）。

为什么要创建一个testClass对象

3 个答案: