java中用于验证的While循环
我想在我的“Member”构造函数中创建一个while循环（要遵循的代码-非常简单），以确保成员id是10个字符，或者pin码是4个字符 e、 g.而id/pinNumber id的长度不是10/4 停止正在创建的构造函数 打印“请输入一个id/pinNumber，长度为10/4个字符” 这是我的密码java中用于验证的While循环,java,Java,我想在我的“Member”构造函数中创建一个while循环（要遵循的代码-非常简单），以确保成员id是10个字符，或者pin码是4个字符 e、 g.而id/pinNumber id的长度不是10/4 停止正在创建的构造函数 打印“请输入一个id/pinNumber，长度为10/4个字符” 这是我的密码 /** * Constructor for objects of class Member */ public Member(String giveName, String giveID,
/**
* Constructor for objects of class Member
*/
public Member(String giveName, String giveID, String givePinNumber, int giveMoney)
{
memberName = giveName;
id = giveID;
if(id.length() > 10)
System.out.println("Please input an id less than 10 characters");
pinNumber = givePinNumber;
if(pinNumber.length() > 10)
System.out.println("Please input a pinNumber less than 10 characters");
store = null;
item = null;
money = giveMoney;
}
我认为这种验证属于视图层： *询问价值观 *验证 *显示错误并询问正确的值 调用构造函数时，传递给它的数据必须是ok 因此，您不需要在构造函数中进行验证
实际上，构造函数的目标是初始化类的字段。没有验证，也不会抛出异常。我认为这种验证属于视图层： *询问价值观 *验证 *显示错误并询问正确的值 调用构造函数时，传递给它的数据必须是ok 因此，您不需要在构造函数中进行验证
实际上，构造函数的目标是初始化类的字段。没有验证，也不会抛出异常。因为这个问题似乎吸引了非常广泛/完全错误的答案，我将在这里尝试澄清一些事情： 可以在构造函数中循环以从控制台获取输入，但我强烈建议不要使用这种代码：
Member(String giveName, String giveID, String givePinNumber, int giveMoney) {
Scanner sc = new Scanner(System.in);
id = giveID;
while (id.length() != 10) {
System.out.println("Enter id with length of 10: ");
id = sc.nextLine();
}
pinNumber = givePinNumber;
while (pinNumber.length() != 4) {
System.out.println("Enter pin-number with length of 4: ");
pinNumber = sc.nextLine();
}
store = null;
item = null;
money = giveMoney;
sc.close();
}
通常这将由创建成员对象的人完成！如果成员对象是在我的主方法中创建的，则可以/将执行以下操作：
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String id;
System.out.println("Please enter id: (length must be 10)");
while ((id = sc.nextLine()).length() != 10)
System.out.println("Length of id must be 10, try again: ");
String pin;
System.out.println("Please enter id: (length must be 10)");
while ((pin = sc.nextLine()).length() != 4)
System.out.println("Length of pin must be 4, try again: ");
sc.close();
Member foo = new Member("Peter", id, pin, 1000000);
}
Member(String giveName, String giveID, String givePinNumber, int giveMoney) {
if (giveID.length() != 10)
throw new IndexOutOfBoundsException("ID-length must be 10!");
if (givePinNumber.length() != 4)
throw new IndexOutOfBoundsException("PIN-length must be 4!");
id = giveID;
pinNumber = givePinNumber;
store = null;
item = null;
money = giveMoney;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String id;
System.out.println("Please enter id: (length must be 10)");
while ((id = sc.nextLine()).length() != 10)
System.out.println("Length of id must be 10, try again: ");
String pin;
System.out.println("Please enter id: (length must be 10)");
while ((pin = sc.nextLine()).length() != 4)
System.out.println("Length of pin must be 4, try again: ");
sc.close();
Member foo = new Member("Peter", id, pin, 1000000);
}
Member(String giveName, String giveID, String givePinNumber, int giveMoney) {
if (giveID.length() != 10)
throw new IndexOutOfBoundsException("ID-length must be 10!");
if (givePinNumber.length() != 4)
throw new IndexOutOfBoundsException("PIN-length must be 4!");
id = giveID;
pinNumber = givePinNumber;
store = null;
item = null;
money = giveMoney;
}
此方法将使您的代码清晰易读，但更重要的是：可重用！考虑一个java应用程序，你没有控制台…您将无法再使用您的成员类 由于这个问题似乎吸引了非常广泛/非常错误的答案，我将尝试在这里澄清一些事情： 可以在构造函数中循环以从控制台获取输入，但我强烈建议不要使用这种代码：
Member(String giveName, String giveID, String givePinNumber, int giveMoney) {
Scanner sc = new Scanner(System.in);
id = giveID;
while (id.length() != 10) {
System.out.println("Enter id with length of 10: ");
id = sc.nextLine();
}
pinNumber = givePinNumber;
while (pinNumber.length() != 4) {
System.out.println("Enter pin-number with length of 4: ");
pinNumber = sc.nextLine();
}
store = null;
item = null;
money = giveMoney;
sc.close();
}
通常这将由创建成员对象的人完成！如果成员对象是在我的主方法中创建的，则可以/将执行以下操作：
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String id;
System.out.println("Please enter id: (length must be 10)");
while ((id = sc.nextLine()).length() != 10)
System.out.println("Length of id must be 10, try again: ");
String pin;
System.out.println("Please enter id: (length must be 10)");
while ((pin = sc.nextLine()).length() != 4)
System.out.println("Length of pin must be 4, try again: ");
sc.close();
Member foo = new Member("Peter", id, pin, 1000000);
}
Member(String giveName, String giveID, String givePinNumber, int giveMoney) {
if (giveID.length() != 10)
throw new IndexOutOfBoundsException("ID-length must be 10!");
if (givePinNumber.length() != 4)
throw new IndexOutOfBoundsException("PIN-length must be 4!");
id = giveID;
pinNumber = givePinNumber;
store = null;
item = null;
money = giveMoney;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String id;
System.out.println("Please enter id: (length must be 10)");
while ((id = sc.nextLine()).length() != 10)
System.out.println("Length of id must be 10, try again: ");
String pin;
System.out.println("Please enter id: (length must be 10)");
while ((pin = sc.nextLine()).length() != 4)
System.out.println("Length of pin must be 4, try again: ");
sc.close();
Member foo = new Member("Peter", id, pin, 1000000);
}
Member(String giveName, String giveID, String givePinNumber, int giveMoney) {
if (giveID.length() != 10)
throw new IndexOutOfBoundsException("ID-length must be 10!");
if (givePinNumber.length() != 4)
throw new IndexOutOfBoundsException("PIN-length must be 4!");
id = giveID;
pinNumber = givePinNumber;
store = null;
item = null;
money = giveMoney;
}
此方法将使您的代码清晰易读，但更重要的是：可重用！考虑一个java应用程序，你没有控制台…您将无法再使用您的成员类 在构造函数中这样做是很少见的，但这是你的决定。但是，你的问题是什么？酷，现在你的问题是什么？？如果您希望
sysoutnulllength（）sysoutnulllength（）之前应检查这些参数