无法从静态上下文引进非静态方法nextInt(),如何解决?

[alexander_woo]

新手上路,还请各位大侠多多指教~!~
import java.util.Scanner;
public class CircleDemo
{
public void main(String[] args)
{
System.out.printf("选择要画的圆的类型: 1.实心圆 ; 2.空心圆\n");
/* Scanner scanner = new Scanner(System.in); */
System.out.printf("你输入的数字是:",Scanner.nextInt());///显示这一行有错!无法从静态上下文中引进非静态方法nextInt();
if(Scanner.nextInt()==1)//同样的错误!
{
System.out.printf("请输入要画的实心圆的半径:");
Scanner scanner = new Scanner(System.in);
int num =scanner.nextInt();
renderCircle (new ConcreteCircle(num));
}

else
{
System.out.printf("请输入要画的空心圆的半径:");
Scanner scanner = new Scanner(System.in);
int num = scanner.nextInt();
renderCircle (new HollowCircle(num));
}
}
public void renderCircle(AbstractCircle circle)
{
circle.render();
}
}

[joejoe1991]

import java.util.Scanner;
public class test
{
public void main(String[] args)
{
System.out.printf("选择要画的圆的类型: 1.实心圆 ; 2.空心圆\n");
Scanner scanner = new Scanner(System.in);
System.out.printf("你输入的数字是:",scanner.nextInt());///显示这一行有错!无法从静态上下文中引进非静态方法nextInt();
if(scanner.nextInt()==1)//同样的错误!
{
System.out.printf("请输入要画的实心圆的半径:");

int num =scanner.nextInt();
renderCircle (new ConcreteCircle(num));
}

else
{
System.out.printf("请输入要画的空心圆的半径:");

int num = scanner.nextInt();
renderCircle (new HollowCircle(num));
}
}
public void renderCircle(AbstractCircle circle)
{
circle.render();
}
}

[ronald108]

就是Scanner类中的nextInt()不是静态方法.所以不能通过Scanner.nextInt()直接调用nextInt()
必须先把Scanner实例化,再通过实例调用nextInt;

Scanner scanner = new Scanner();
scanner.nextInt();

[weiqiyiji]

int scan = Scanner.nextInt();
然后用scan代替scanner.nextInt()就可以了

[Yanbin_Q]

要知道为什么不允许这种调用，可以从两种方面来讲：

1、非静态方法需要通过实例来调用，而你在调用静态方法时可能并不产生相应实例，所以不允许
2、非静态方法调用会传递一个隐形参数 this，调用静态方法则不需要，在静态方法中可能根本就不存在相应类型的 this