Java自行车和自行车测试

Question

我在编写代码时遇到问题。在这段代码中，我必须创建一个对象类并使用另一个类对象运行它。 该程序称为自行车和自行车测试。 我得到了自行车程序(它已经写好了)，我需要编写自行车测试来使用自行车。 现在的问题是，我创建了 2 个对象，分别称为 NiceBicycle 和 CoolBicycle。我需要将 NiceBicycle 名称更改为“Kenny McCormick”，但我做不到。我不断收到错误消息 对于我编写的这行命令，“错误:变量 NiceBicycle 可能尚未初始化”。

//使用 setOwnerName 将所有者名称更改为 Kenny McCormick NiceBicycle.setOwnerName("肯尼·麦考密克");

我该怎么办？

无论如何，这是我根据教练命令编写的自行车代码和自行车测试。 谢谢您的回复

自行车.java

public class Bicycle
{

// Instance field
private String ownerName;
private int licenseNumber;

// Constructor
public Bicycle( String name, int license )
{
     ownerName = name;
     licenseNumber = license;
}

// Returns the name of this bicycle's owner
public String getOwnerName()
{
     return ownerName;
}

// Assigns the name of this bicycle's owner
public void setOwnerName( String name )
{
     ownerName = name;
}

// Returns the license number of this bicycle
public int getLicenseNumber()
{
     return licenseNumber;
}

// Assigns the license number of this bicycle
public void setLicenseNumber( int license ) 
{
     licenseNumber = license;
}

}

这是我编写的 biketest.java。

  public class BicycleTest 
   {

    public static void main( String[] args )
    {

    // Create 1 Bicycle reference variable. For example: myBike
    Bicycle NiceBicycle;

    // Create 1 String reference variable for the owner's name
    String name;

    // Create 1 integer variable for license number
    int licenceNumber;

    // Assign your full name and a license number to the String and
    // integer variables
    name = "Boo Yeah";
    int licenseNumber = 9972;

    // Create a Bicycle object with the Bicycle class constructor
    // Use the variables you created as arguments to the constructor
    Bicycle CoolBicycle = new Bicycle( "Boo Yeah", 9972 );

    // Output the owner's name and license number in printf statements
    // using the object reference and the get methods.
    // For example: bike.getOwnerName()
    System.out.printf ("The CoolBicycle owner's name is %s\nThe license number is %d\n", CoolBicycle.getOwnerName(), CoolBicycle.getLicenseNumber());

    // Change the owner's name to Kenny McCormick using setOwnerName
    NiceBicycle.setOwnerName("Kenny McCormick");

    // Output the owner's name and license number in printf statements
      // using the Bicycle object reference variable and the get methods.
      System.out.printf ("The NiceBicycle owner's name is %s\n", NiceBicycle.getOwnerName());
 }

}

Answer 1

您需要实例化 Bicycle 并将其分配给测试中的 NiceBicycle，方法是更改​​:

Bicycle NiceBicycle;

至:

Bicycle NiceBicycle = new Bicycle("", 0);

然后你可以对其进行 setOwnerName() :

NiceBicycle.setOwnerName("Kenny McCormick");

另请注意，Java 约定建议变量名称以小写字母开头，因此如果您想遵循 Java 约定，NiceBicycle 应该是 niceBicycle。