Possible issue with Java 7

[John Starr]

I am working on this tutorial and having a few issues. Here is the problem "Create a file using any word-processing program or text editor. Write an application that displays the file's name, containing folder, size, and time of last modification. Save file as FileStatistics.java"

Here is what I have:

import java.nio.file.*;
import java.nio.file.attribute.*;
import java.nio.file.attribute.Attributes;
import java.io.IOException;
public class FileStatistics
{
   public static void main(String[] args)
   {
      Path file =
         Paths.get("C:\\Java\\Chapter.13\\TestData.txt");
      try
      {
         int count = file.getNameCount();
         System.out.println("Path is " + file.toString());
         System.out.println("File name is " + file.getName());
         System.out.println("Folder name is " + file.getName(count - 2));
         BasicFileAttributes attr =
            Attributes.readBasicFileAttributes(file);
         System.out.println("File's size is " + attr.size());
         FileTime time = attr.creationTime();
         System.out.println("File's creation time is " + time);       
      }
      catch(IOException e)
      {
          System.out.println("IO Exception");
      }
   }
}

And this is the errors that I receive when I try to compile it: (I am using jGRASP)

----jGRASP exec: javac -g FileStatistics.java

FileStatistics.java:3: error: cannot find symbol
import java.nio.file.attribute.Attributes;
^
symbol: class Attributes
location: package java.nio.file.attribute
FileStatistics.java:15: error: method getName in interface Path cannot be applied to given types;
System.out.println("File name is " + file.getName());
^
required: int
found: no arguments
reason: actual and formal argument lists differ in length
FileStatistics.java:18: error: cannot find symbol
Attributes.readBasicFileAttributes(file);
^
symbol: variable Attributes
location: class FileStatistics
3 errors

----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.

I think I may be getting errors because of some compatibility issues with Java 7. Is there anything you can see that might be causing it?

Thanks,

-John

Sana: Added code tags

[Paul Clapham]

Sorry, as far as I can see the errors are all yours.

The compiler is correct to say there is no "java.nio.file.attribute.Attributes" type. It's correct to say that the getName() method of Path requires an int parameter. At least based on my reading of the API documentation for Java 7, that's the case. Is there some reason you disagreed with those error messages?

[John Starr]

Hey Paul, the thing I was wondering about was this error:

BasicFileAttributes attr =
Attributes.readBasicFileAttributes(file);

I read the other topic post by Sverre Moe that talked about the Java 7 Confusion and here is what was said.


According to many different tutorials there are some differences to the official JDK7.

Interface FileRef is not in JDK7
References to path.copyTo, but method does not exist. Must instead use Files.copy
References to a class called Attributes, but does not exist. BasicFileAttributes basic = Attributes.readBasicFileAttributes. Must instead use Files.getFileAttributeView.


Would I have to replace

BasicFileAttributes attr =
Attributes.readBasicFileAttributes(file);

with Files.getFileAttributeView? Sorry, I am a noob at this. I think I fixed the other 2 errors I had.

[Paul Clapham]

I'm sorry, I haven't used those features in Java 7, all I did was to look in the API docs. I assume you must be working from an old example which was written back when Java 7 was still being designed? In that case I would suggest looking for a new tutorial. Like this one which I just googled up with keywords "java file tutorial". Looks like it's been updated to cover Java 7.

[John Starr]

I have another question for you, also let me know if I am posting these things in the wrong thread for this forum. I have this code here:

import java.util.*;
import java.io.*;
import java.text.*;
import java.util.Date;
public class FileIn

{
	public static void main(String[] args)throws FileNotFoundException
	{
		int count=0,i;
		String filename,dates;
		long datetime;
		SimpleDateFormat sdf=new SimpleDateFormat("dd-MM-yyyy hh:mm:ss");
		double[]number =new double[30];
		System.out.print("enter file name ");
		filename=in.nextLine();
		File f=new File(filename);
		System.out.println("File Name: "+filename);
		System.out.println("Folder: "+f.getAbsolutePath());     
		System.out.println("Size: "+f.length()+" bytes");
		datetime=f.lastModified();
		Date d=new Date(datetime);
		dates=sdf.format(d);
		System.out.println("Last modified: " +dates);
 }
}

I want to change the file name to FileStatistics but when I change the public class to FileStatistics I get this error code:

FileStatistics.java:16: error: cannot find symbol
filename=in.nextLine();
^
symbol: variable in
location: class FileStatistics
1 error

What do I have to do to change the File name where I won't get error codes when I compile?

[Rob Spoor]

There is no class java.nio.file.attribute.Attributes. If you check the Javadoc of BasicFileAttributes you see that the way to get these is using java.nio.file.Files:

BasicFileAttributes attrs = Files.readAttributes(file, BasicFileAttributes.class);

[Rob Spoor]

John Starr wrote:What do I have to do to change the File name where I won't get error codes when I compile?

What should in be? I'm guession you forgot this line:

Scanner in = new Scanner(System.in);