Question

这是我的问题：

我正在尝试使用Scanner和System.in从键盘获取输入并将其分配给int变量。

这就是我所拥有的（完整程序包含在下面）：

// this program will use scanner objects and system inputs
public class Scanner
{
    public static void main(String[] args)
    {
        int number;  
             // declares integer "number"

        Scanner keyboard = new Scanner(System.in); 
  //-------------------------------------------------------------------
  // declares referance variable (Scanner class) "keyboard", creates       
  // Scanner object that 
  // reads input from System.in, then assigns address of Scanner object 
  // to the reference variable "keyboard"
  //-------------------------------------------------------------------     
        System.out.println("Enter an integer value: ");
             // displays text 
        number = keyboard.nextInt();
            // assigns keyboard input to "number" as integer value

        System.out.println("You entered the integer " + number);
           // displays "number" to see if the program worked
    }
}

当我尝试使用javac在Windows命令提示符下编译程序时，出现此错误消息：

error: constructor Scanner in class Scanner
cannot be applied to given types;

Scanner keyboard = new Scanner(System.in);

required: no arguments
found: InputStream
reason: actual and formal argument lists differ in length

error: cannot find symbol
            number = keyboard.nextInt();
                             ^
symbol:   method nextInt()
location: variable keyboard of type Scanner
2 errors

我做错了什么？

Answer 1

有命名冲突。您必须从Java语言角度使Scanner类成为唯一的，有两个选项可以做到：

重命名课程
- 到其他名称，以便不再有命名冲突

让Scanner班级明确

使用完全限定名称

public static void main(String[] args)
{
    int number;
    java.util.Scanner keyboard = new java.util.Scanner(System.in);

    System.out.println("Enter an integer value: ");

    number = keyboard.nextInt();
    System.out.println("You entered the integer " + number);
}

Answer 2

您应该重命名类Scanner - 错误在于，您使用Java标准库中名为Scanner的类。

Answer 3

import java.util.Scanner;  

public class Main {
    public static void main(String[] args){
        int number;
        Scanner keyboard = new Scanner(System.in);

        System.out.println("Enter an integer value: ");

        number = keyboard.nextInt();
        System.out.println("You entered the integer " + number);

    }
}

将Scanner对象连接到System.in对象并使用扫描程序方法

3 个答案: