FileToString.java

package com.levelup.java.io;

import static org.junit.Assert.assertEquals;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

import org.apache.commons.io.FileUtils;
import org.junit.Before;
import org.junit.Test;

import com.google.common.base.Charsets;
import com.google.common.io.Files;

/**
 * This java example will demonstrate reading a file into a String.
 * 
 * @author Justin Musgrove
 * @see <a href=
 *      'http://www.leveluplunch.com/java/examples/read-file-into-string/'>Read
 *      file into string</a>
 * 
 */
public class FileToString {

	private static final String FILE_PATH = "com/levelup/java/io/file-to-string.txt";
	private URI fileLocation;

	@Before
	public void setUp() throws URISyntaxException {
		fileLocation = this.getClass().getClassLoader().getResource(FILE_PATH)
				.toURI();
	}

	@Test
	public void convert_file_to_string_java_bufferedreader() throws IOException {

		File file = new File(fileLocation);

		BufferedReader br = new BufferedReader(new FileReader(file));
		StringBuffer fileContents = new StringBuffer();
		String line = br.readLine();
		while (line != null) {
			fileContents.append(line);
			line = br.readLine();
		}

		br.close();

		assertEquals("File to string example", fileContents.toString());
	}

	@Test
	public void convert_file_to_string_java_scanner()
			throws FileNotFoundException {

		File file = new File(fileLocation);

		Scanner scanner = new Scanner(file);

		String fileContents = scanner.nextLine(); // only reads line

		scanner.close();

		assertEquals("File to string example", fileContents);
	}

	@Test
	public void convert_file_to_string_java_nio() throws IOException {

		Path path = Paths.get(fileLocation);

		List<String> file = java.nio.file.Files.readAllLines(path,
				Charsets.UTF_8);

		String fileContents = file.get(0);

		assertEquals("File to string example", fileContents);
	}

	@Test
	public void convert_file_to_string_java_nio_readbytes() throws IOException {

		Path path = Paths.get(fileLocation);

		String stringFromFile = new String(
				java.nio.file.Files.readAllBytes(path));

		assertEquals("File to string example", stringFromFile);
	}

	@Test
	public void convert_file_to_string_java8() throws IOException {

		Path path = Paths.get(fileLocation);

		String stringFromFile = java.nio.file.Files.lines(path).collect(
				Collectors.joining());

		assertEquals("File to string example", stringFromFile);
	}

	@Test
	public void convert_file_to_string_guava() throws IOException {

		File file = new File(fileLocation);

		String fileContents = Files.toString(file, Charsets.UTF_8);

		assertEquals("File to string example", fileContents);
	}

	@Test
	public void convert_file_to_string_apache_commons() throws IOException {

		File file = new File(fileLocation);

		String fileContents = FileUtils.readFileToString(file);

		assertEquals("File to string example", fileContents);
	}

}