Question

我正在尝试在java中编写一个创建类的对象的应用程序，并接受用户输入以填充对象的属性，并且如果用户输入无效值，则可以抛出异常。我将异常的条件放在名为Stuff.java的类中的setter方法中，并创建了异常类。我的问题是在包含main方法的类中，我如何对其进行编码以提示用户一个接一个地输入属性值，并且必须继续提示用户输入，直到用户填写了值为三个属性。这是我下面的代码，具有main方法的类并没有真正给我我想要的东西。我必须做些什么改变？

Stuff类：

public class Stuff {
private int howMany;
private String name;
private boolean answer;

public void setHowMany(int howMany) throws InappropriateIntegerValue {
    if (howMany <= 0 || howMany >= 10000) {
        throw new InappropriateIntegerValue("in appropriate value");
    } else {
        this.howMany = howMany;
    }
}

public void setName(String name) throws IllegalStringValue {
    CharSequence car = "!@#%&*";
    if (name.length() < 6 || name.contains(car) != true
            || Character.isAlphabetic(name.charAt(0)) == false) {
        throw new IllegalStringValue("illegal string value");
    } else {
        this.name = name;
    }

}

public void setAnswer(String answer) throws InvalidBooleanValue {
    if (answer == "yes") {
        this.answer = true;
    } else if (answer == "no") {
        this.answer = false;
    } else {
        throw new InvalidBooleanValue("invalid respose");
    }
}

@Override
public String toString() {
    return "Stuff [howMany=" + howMany + ", name=" + name + ", answer="
            + answer + "]";
}

}

非法字符串值的异常类：

public class IllegalStringValue extends RuntimeException {

public IllegalStringValue() {
    // TODO Auto-generated constructor stub
}

public IllegalStringValue(String message) {
    super(message);
    // TODO Auto-generated constructor stub
}

public IllegalStringValue(Throwable cause) {
    super(cause);
    // TODO Auto-generated constructor stub
}

public IllegalStringValue(String message, Throwable cause) {
    super(message, cause);
    // TODO Auto-generated constructor stub
}

public IllegalStringValue(String message, Throwable cause,
        boolean enableSuppression, boolean writableStackTrace) {
    super(message, cause, enableSuppression, writableStackTrace);
    // TODO Auto-generated constructor stub
}

}

非法整数值的异常类

public class InappropriateIntegerValue extends RuntimeException {

public InappropriateIntegerValue() {
    // TODO Auto-generated constructor stub
}

public InappropriateIntegerValue(String message) {
    super(message);
    // TODO Auto-generated constructor stub
}

public InappropriateIntegerValue(Throwable cause) {
    super(cause);
    // TODO Auto-generated constructor stub
}

public InappropriateIntegerValue(String message, Throwable cause) {
    super(message, cause);
    // TODO Auto-generated constructor stub
}

public InappropriateIntegerValue(String message, Throwable cause,
        boolean enableSuppression, boolean writableStackTrace) {
    super(message, cause, enableSuppression, writableStackTrace);
    // TODO Auto-generated constructor stub
}

}

非法布尔值的异常类：

public class InvalidBooleanValue extends RuntimeException {

public InvalidBooleanValue() {
    // TODO Auto-generated constructor stub
}

public InvalidBooleanValue(String message) {
    super(message);
    // TODO Auto-generated constructor stub
}

public InvalidBooleanValue(Throwable cause) {
    super(cause);
    // TODO Auto-generated constructor stub
}

public InvalidBooleanValue(String message, Throwable cause) {
    super(message, cause);
    // TODO Auto-generated constructor stub
}

public InvalidBooleanValue(String message, Throwable cause,
        boolean enableSuppression, boolean writableStackTrace) {
    super(message, cause, enableSuppression, writableStackTrace);
    // TODO Auto-generated constructor stub
}

}

使用main方法的类，这是我认为我遇到错误的地方：

import java.util.Scanner;

public class Application {

public static void main(String[] args) {
    Stuff stf = new Stuff();
    Scanner userIn = new Scanner(System.in);
    int howMany;
    String name;
    String answer;

    System.out.println("enter number");
    howMany = userIn.nextInt();

    System.out.println("enter name");
    name = userIn.nextLine();

    System.out.println("enter answer");
    answer = userIn.nextLine();

    stf.setHowMany(howMany);
    stf.setAnswer(answer);
    stf.setName(name);

}

}

Answer 1

您的nextInt()函数中的

问题只是读取整数值，当您按下输入时，它会跳过nextLine()。

在您的主要方法中尝试userIn.nextLine();。

Scanner userIn = new Scanner(System.in);
int howMany;
String name;
String answer;

System.out.println("enter number");
howMany = userIn.nextInt();

System.out.println("enter name");
userIn.nextLine();
name = userIn.nextLine();

System.out.println("enter answer");
answer = userIn.nextLine();

java异常和扫描程序输入

1 个答案: