checkforread.java

《A first book of java》by Gary J.Bronson 北大出版社

import java.io.*;
public class CheckForRead
{
  public static void main(String[] args)
    throws java.io.IOException
  {
    String fileName = "prices.dat";

    File inFile = new File(fileName);
  
      // check that the file exists and can be read
    if (inFile.exists() == false)
    {
      System.out.println("The file " + fileName + " does not exist - please check and rerun.");
      System.exit(1);
    }
    else if(inFile.canRead() == false)
    {
      System.out.println("The file " + fileName + " exists but does not have read permission - please check.");
      System.exit(1);
    }

       // set up the input stream and read the file

    System.out.println("The file " + fileName + " exists and can be read.");

  }
}