如何捕获回车键，使用扫描仪作为控制台输入?

问题描述：

我想在控制台中捕获输入字符.我正在输入 2 个字符串.

I want to capture enter character in console. I am inputting 2 strings.

案例 1. removestudent(按 Enter)从数组列表中删除所有学生.

Case 1. removestudent(pressing enter) removes all the students from array list.

案例 2. removestudent student1 从数组列表中删除 student1.

Case 2. removestudent student1 removes students1 from array list.

Scanner in=new Scanner();

type_op=in.next();

param=in.next();

if (type_op.equals("removestudent"))
{

    //Calling remove student function and passing param over here.

}

现在案例 2 工作正常.但是，对于案例 1，当用户按下 Enter 键时，我希望参数值为 null.然后我将 param 作为空值传递给我的 remove 函数并删除数组列表中的所有学生.

Now the case 2 works fine. However, for Case 1, I want param value to be null when user presses enter. I will then pass param as a null value to my remove function and delete all the students in the array list.

list1.clear();

请帮助我知道如何获得这个回车键.

Please help me in knowing how to get this enter key.

答

你可以读取 line，如果 line 是空的，你可以假设它是 enter key.. 就像下面的代码..

You can read line and if line is blank, You can assume it is enter key.. like below code..

Scanner scanner = new Scanner(System.in);
String readString = scanner.nextLine();
System.out.println(readString);
if (readString.equals(""))
    System.out.println("Enter Key pressed.");
if (scanner.hasNextLine())
    readString = scanner.nextLine();
else
    readString = null;

如何捕获回车键，使用扫描仪作为控制台输入?

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