Question

1. In the root of the project create a folder called res. In that folder create a file called DemoFile.txt
2. Create a class with a static main that tests the ability to resolve and print a Path:
   • Create an instance of a FileSystem class.
   • Create an instance of the Path interface for the DemoFile.txt file. Print the constructed Path with System.out.println() method.

2. Create a class that does the following:
   • Using a pre-Java 7 solution, create a class that tests streams in the static main.
   • The class should instantiate a new File class, a new FileReader class, and new BufferedReader class.
   • Read lines by using the readLine() method call.
   • The file path used should be: <home directory of the current project>/res/employees.txt
   • The file should handle errors when the file is not found as well as reading the contents of the file when it is found

Answer 1

package filesystem;

// Defines an interface Path
public interface Path
{
   // Constants stores the current path
   public static final String FILEPATH = "E:/Workspace/Student/";
   // Method to return file path
   public String getPath();
}// End of interface
-------------------------------------------------------------------------------------------------

package filesystem;

// Defines class FileSystem implements interface Path
public class FileSystem implements Path
{
   // Overrides method of Path interface to return file path
   public String getPath()
   {
       return FILEPATH;
   }// End of method
}// End of FileSystem
-------------------------------------------------------------------------------------------------

package filesystem;

import java.io.*;
// Defines driver class FileSystemTest
public class FileSystemTest
{
   // main method definition
   public static void main(String []ss)throws IOException
   {
       // Calls the method to get file path
       String path = new FileSystem().getPath();
       // Displays the path
       System.out.println("\n Current Path: " + path);
       // To store file name
       String fileName;
       // Declares an object of class BufferedReader for file
       BufferedReader fileBr = null;
       // Declares an object of class BufferedReader for console
       BufferedReader input = null;
       // Declares an object class File for file operation
       File file = null;
       // Declares an object of FileReader to read file
       FileReader fileReader = null;
      
       try
       {
           // Creates the object to accept data from console
           input = new BufferedReader(new InputStreamReader(System.in));
           // Accepts the file name
           System.out.print("\n Enter the file name: ");
           fileName = input.readLine();
          
           // Generates file path
           file = new File(path + fileName);
           // Opens the file for reading
           fileReader = new FileReader(file);
           // Attach buffered reader to file reader
           fileBr = new BufferedReader(fileReader);
           String line;
           // Loops till end of the file and reads a line
while ((line = fileBr.readLine()) != null)
   // Displays the line
   System.out.println(line);
       }// End of try block
      
       // Closing operation
       finally
       {
           fileBr.close();          
           input.close();
           fileReader.close();
}// End of finally
   }// End of main method
}// End of driver class

Sample Output:

Current Path: E:/Workspace/Student/

Enter the file name: employeeData.txt
Pyari Sahu P111 89.99 80
Sasmita Sahu S121 78.12 60
Ram Panda R122 32.12 12
Anil Sharma A211 45.7 30
Rohit Panda R133 16.36 19
Tanvi Sahu 2T21 79.91 65
Manvi Sahu M331 92.99 70
Binod Sharma B129 61.33 22