Ruby vs Java - Read and Write Text Files

This post demonstrates how to read and write text files in several scenarios. It makes some short references to equivalent Java concepts and codes.

Ruby, Java, and Others

Here is some information about the environment used for this Ruby post.

Windows 10
Windows command line
Notepad++
Ruby for Windows
- ruby 2.3.1p112 (2016-04-26 revision 54768) [x64-mingw32]
- http://ruby-doc.org/core-2.3.1/
Java 8 – JDK
Eclipse Mars

Reading and Writing Files

Reading and writing files in Ruby require the use of the Class IO which is part of Ruby’s Core API. Think of it like the Java IO package.

Read and Write in Bulk

In Ruby

# Read the whole content of file in_data.txt
text_data = IO.read("in_data.txt")

# Display the read text data
print text_data

# Write the text data to out_data.txt
IO.write("out_data.txt", text_data)

# Read the whole content of file in_data.txt

text_data = IO.read("in_data.txt")

# Display the read text data

print text_data

# Write the text data to out_data.txt

IO.write("out_data.txt", text_data)

In Java

The equivalent Java codes are as follows.

import java.io.IOException;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Paths;

public class MyClass {
	public static void main(String[] args) throws IOException {

		String contents = new String(Files.readAllBytes(Paths.get("C:\\SOMEWHERE\\in_data.txt")));
		System.out.println(contents);
		
		try( PrintWriter out = new PrintWriter( "C:\\SOMEWHERE\\out_data.txt" )  ){
		    out.println( contents );
		}
	}
}

import java.io.IOException;

import java.io.PrintWriter;

import java.nio.file.Files;

import java.nio.file.Paths;

public class MyClass {

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

String contents = new String(Files.readAllBytes(Paths.get("C:\\SOMEWHERE\\in_data.txt")));

System.out.println(contents);

try( PrintWriter out = new PrintWriter( "C:\\SOMEWHERE\\out_data.txt" ) ){

out.println( contents );

}

Read and Write line by line

In Ruby

file = File.open("out_data.txt", "w")
IO.foreach("in_data.txt") {
	|text_data| print text_data
	file.write(text_data)
}

file = File.open("out_data.txt", "w")

IO.foreach("in_data.txt") {

|text_data| print text_data

file.write(text_data)

}

In Java

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Paths;

public class MyClass {
	public static void main(String[] args) throws IOException {
		InputStream is = new FileInputStream("C:\\SOMEWHERE\\in_data.txt");
		BufferedReader buf = new BufferedReader(new InputStreamReader(is));


		File fout = new File("C:\\SOMEWHERE\\out_data.txt");
		FileOutputStream fos = new FileOutputStream(fohttps://turreta.com/blog/wp-admin/post.php?post=1661&action=edit#ut);
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos));
		
		String line = null;
		while ((line = buf.readLine()) != null) {
			bw.write(line);
			bw.newLine();
		}
		buf.close();
		bw.close();
	}
}