java - 尝试使用 Dr.Java 打开文件时出现编译错误

Question

所以我目前正在大学学习java入门类(class)，到目前为止我已经成功地找出并解决了问题。到目前为止。当我尝试打开和读取文件时遇到某种编译错误。我按照我的课本及其基本代码的设定说明来执行此操作，但最终以错误告终。然后我从我的书中取出源代码并将其放入 Dr.Java 中，但它仍然编译错误，这是来自书中的。所以我不太确定问题是什么，想知道是否有人可以引导我走向正确的方向。供引用。总是同样的两个错误。谢谢。

import java.util.Scanner; // Needed for the Scanner class
import java.io.*;         // Needed for the File class

/**
   This program reads data from a file.
*/

public class FileReadDemo
{
   public static void main(String[] args) throws IOException
   {
      // Create a Scanner object for keyboard input.
      Scanner keyboard = new Scanner(System.in);

      // Get the filename.
      System.out.print("Enter the filename: ");
      String filename = keyboard.nextLine();

      // Open the file.
      File file = new File(filename);
      Scanner inputFile = new Scanner(file);

      // Read lines from the file until no more are left.
      while (inputFile.hasNext())
      {
         // Read the next name.
         String friendName = inputFile.nextLine();

         // Display the last name read.
         System.out.println(friendName);
      }

      // Close the file.
      inputFile.close();
   }
}

这是不断发生的错误代码。

发现 2 个错误:

File: C:\Users\aspea\Documents\Intro to Computers and Java\FileReadDemo.java  [line: 20]
Error: constructor File in class File cannot be applied to given types;
  required: no arguments
  found: java.lang.String
  reason: actual and formal argument lists differ in length

File: C:\Users\aspea\Documents\Intro to Computers and Java\FileReadDemo.java  
[line: 21]
Error: no suitable constructor found for Scanner(File)
    constructor java.util.Scanner.Scanner(java.lang.Readable) is not applicable
      (argument mismatch; File cannot be converted to java.lang.Readable)
    constructor java.util.Scanner.Scanner(java.io.InputStream) is not applicable
      (argument mismatch; File cannot be converted to java.io.InputStream)
    constructor java.util.Scanner.Scanner(java.io.File) is not applicable
      (argument mismatch; File cannot be converted to java.io.File)
    constructor java.util.Scanner.Scanner(java.nio.file.Path) is not applicable
      (argument mismatch; File cannot be converted to java.nio.file.Path)
    constructor java.util.Scanner.Scanner(java.lang.String) is not applicable
      (argument mismatch; File cannot be converted to java.lang.String)
    constructor java.util.Scanner.Scanner(java.nio.channels.ReadableByteChannel) is not applicable
      (argument mismatch; File cannot be converted to java.nio.channels.ReadableByteChannel)

Answer 1

您似乎有一些自定义的File类，它不是java.io.File，以下错误表明了这一事实:

Error: constructor File in class File cannot be applied to given types;
  required: no arguments
  found: java.lang.String
  reason: actual and formal argument lists differ in length

还有

File cannot be converted to java.io.File