无法使用Scanner类,构造函数未定义,方法未定义

Question

当我想在我的项目中导入扫描器类时eclipse向我展示一些错误:

 Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
  The constructor Scanner(InputStream) is undefined
  The method nextLine() is undefined for the type Scanner

这是我的代码:

import java.util.Scanner;

public class Scanner {

    public static void main(String[] args) {

        Scanner myScanner = new Scanner(System.in);
        System.out.println(myScanner.nextLine());

    }

}

Answer 1

问题是你还要声明一个叫做的类Scanner.这意味着当你然后声明一个类型的变量Scanner并尝试调用构造函数时,编译器会认为你在谈论你的类.只需将自己的类更改为其他类(例如Test):

import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        Scanner myScanner = new Scanner(System.in);
        System.out.println(myScanner.nextLine());
    }
}

或者你可以在你的意思上完全限定名称java.util.Scanner- 但就可读性而言,这是一个坏主意.

// Please don't do this - but it would work.
public class Scanner {
    public static void main(String[] args) {
        java.util.Scanner myScanner = new java.util.Scanner(System.in);
        System.out.println(myScanner.nextLine());
    }
}