嘗試使用Dr.Java打開文件時編譯錯誤

Question

因此，我目前正在大學里學習Java課程，到目前為止，我已經成功地解決了問題並解決了問題。 到現在。 嘗試打開和讀取文件時出現某種編譯錯誤。 我按照班級教科書的基本說明進行設置，但這樣做以錯誤告終。 然后，我從書中獲取源代碼，並將其放入Dr.Java中，但仍然編譯錯誤，而那是書中的內容。 因此，我不確定問題出在哪里，並且想知道是否有人可以引導我朝正確的方向前進。 僅供參考，它總是兩個相同的錯誤。 謝謝。

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();
   }
}

這是不斷發生的錯誤代碼。

找到2個錯誤：

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

看來您有一些不是java.io.File自定義File類，以下錯誤表明了這一事實：

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

和

File cannot be converted to java.io.File