Java I/O Java IO You will be reading from and writing to files. You should promp

Question

Java I/O

Java IO

You will be reading from and writing to files. You should prompt the user for a manifest file name, which should contain the name of additional files, one per line. Then, you should read the contents of each of these files and write them to a single new file. The name of the new file should be the name of the manifest with the additional extension .out. If there is a problem reading or writing to a file, you should print an appropriate error message. If you try to read a file from your project, it will look for it in the application root. This is inside the same folder as src. Place new files there (Right-Click on project in workspace, then File > New File to create an empty, extension-less file).

Input files

manifest.txt

file1.txt Hello
file2.txt World
file3.txt How are you?

Output

Enter manifest filename: manifest.txt

manifest.txt.out
Hello
World
How are you?

package lab10;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

Code Template:

public class L10 {

   public static void main(String[] args) {
       System.out.println("input manifest file name");
      
       Scanner in = new Scanner(System.in);
       String name = in.nextLine();
      
       // TODO
       // create a reader and writer object
       // use the reader to read the names of input files from the manifest file and
       // for each file name, use the same reader to read the content of the file, and write to the output file.
       // don't forget to flush the writer in the end
      
       in.close();
   }
}

Explanation / Answer

L10.java

import java.io.File;

import java.io.FileNotFoundException;

import java.io.PrintWriter;

import java.util.Scanner;

public class L10 {

public static void main(String[] args) throws FileNotFoundException {

System.out.println("input manifest file name");

Scanner in = new Scanner(System.in);

String name = in.nextLine();

// TODO

// create a reader and writer object

// use the reader to read the names of input files from the manifest file and

// for each file name, use the same reader to read the content of the file, and write to the output file.

// don't forget to flush the writer in the end

File file = new File(name);

if(file.exists()) {

Scanner scan = new Scanner(file);

File outputFile = new File(name+".out");

PrintWriter pw = new PrintWriter(outputFile);

while(scan.hasNextLine()) {

String fileName = scan.nextLine();

File inFile = new File(fileName);

Scanner read = new Scanner(inFile);

while(read.hasNextLine()) {

pw.write(read.nextLine()+" ");

}

read.close();

}

pw.flush();

pw.close();

scan.close();

System.out.println("File has been generated");

} else {

System.out.println("File does not exist");

}

in.close();

}

}

Output:

input manifest file name
D://manifest.txt
File has been generated

manifest.txt.out
Hello
World
How are you?

Related Questions

Navigate

• Browse (All)
• Browse J
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.