我想创建一个不能为空的扫描仪。因此,当按下enter键时,扫描仪中没有任何东西,我想发出警告信息。我有这段代码
if (user_input.hasNext())// only if scanner is empty and enter is pressed{
System.out.println("Scanner can not be empty");
}
Scanner sc=new Scanner(System.in);
String input = sc.nextLine();
if(input.isEmpty())
{
System.out.println("Scanner can not be empty");
}