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Eugen
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Merge pull request eugenp#48 from Doha2012/master
add TestReader to test Read from file
2 parents f024fd8 + d1bc7d2 commit a951961

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‎core-java/src/test/java/org/baeldung/java/io/TestReader.java‎

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package org.baeldung.java.io;
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import static org.junit.Assert.assertEquals;
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import static org.junit.Assert.assertTrue;
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import java.io.BufferedOutputStream;
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import java.io.BufferedReader;
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import java.io.BufferedWriter;
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import java.io.DataInputStream;
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import java.io.DataOutputStream;
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import java.io.File;
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import java.io.FileInputStream;
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import java.io.FileOutputStream;
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import java.io.FileReader;
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import java.io.FileWriter;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.io.RandomAccessFile;
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import java.io.SequenceInputStream;
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import java.io.StreamTokenizer;
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import java.nio.ByteBuffer;
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import java.nio.channels.FileChannel;
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import java.nio.file.Files;
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import java.nio.file.Path;
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import java.nio.file.Paths;
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import java.util.Enumeration;
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import java.util.Scanner;
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import java.util.Vector;
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import org.junit.Test;
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/*
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MappedByteBuffer
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*/
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public class TestReader {
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@Test
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public void whenReadWithBufferedReader_thenCorrect() throws IOException {
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final String str = "Hello world";
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final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
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writer.write(str);
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writer.close();
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final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/test_read.txt"));
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final String currentLine = reader.readLine();
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reader.close();
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assertEquals(str, currentLine);
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}
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@Test
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public void whenReadWithScanner_thenCorrect() throws IOException {
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final String str = "Hello world 1 2,3,4";
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final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
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writer.write(str);
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writer.close();
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final Scanner scanner = new Scanner(new File("src/test/resources/test_read.txt"));
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scanner.useDelimiter(" ");
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assertTrue(scanner.hasNext());
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assertEquals("Hello", scanner.next());
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assertEquals("world", scanner.next());
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assertEquals(1, scanner.nextInt());
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scanner.useDelimiter(",| ");
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assertTrue(scanner.hasNextInt());
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assertEquals(2, scanner.nextInt());
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assertEquals(3, scanner.nextInt());
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assertEquals(4, scanner.nextInt());
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scanner.close();
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}
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@Test
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public void whenReadWithStreamTokenizer_thenCorrectTokens() throws IOException {
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final String str = "Hello 1";
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final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
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writer.write(str);
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writer.close();
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final FileReader reader = new FileReader("src/test/resources/test_read.txt");
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final StreamTokenizer tokenizer = new StreamTokenizer(reader);
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tokenizer.nextToken();
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assertEquals(StreamTokenizer.TT_WORD, tokenizer.ttype);
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assertEquals("Hello", tokenizer.sval);
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tokenizer.nextToken();
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assertEquals(StreamTokenizer.TT_NUMBER, tokenizer.ttype);
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assertEquals(1, tokenizer.nval, 0.0000001);
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tokenizer.nextToken();
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assertEquals(StreamTokenizer.TT_EOF, tokenizer.ttype);
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reader.close();
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}
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@Test
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public void whenReadWithDataInputStream_thenCorrect() throws IOException {
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final String value = "Hello";
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final DataOutputStream outStream = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("src/test/resources/test_read.txt")));
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outStream.writeUTF(value);
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outStream.close();
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String result;
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final DataInputStream reader = new DataInputStream(new FileInputStream("src/test/resources/test_read.txt"));
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result = reader.readUTF();
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reader.close();
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assertEquals(value, result);
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}
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public void whenReadTwoFilesWithSequenceInputStream_thenCorrect() throws IOException {
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final int value1 = 2000;
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final int value2 = 5000;
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FileOutputStream writer = new FileOutputStream("src/test/resources/test_read.txt");
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writer.write(value1);
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writer.close();
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writer = new FileOutputStream("src/test/resources/test_read1.txt");
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writer.write(value2);
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writer.close();
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final FileInputStream stream1 = new FileInputStream("src/test/resources/test_read.txt");
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final FileInputStream stream2 = new FileInputStream("src/test/resources/test_read1.txt");
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final SequenceInputStream sequence = new SequenceInputStream(stream1, stream2);
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final DataInputStream reader = new DataInputStream(sequence);
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assertEquals(value1, reader.readInt());
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assertEquals(value2, reader.readInt());
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reader.close();
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stream2.close();
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}
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@Test
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public void whenReadAllFilesInFolder_thenCorrect() throws IOException {
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final File dir = new File("src/test/resources");
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final File[] allFiles = dir.listFiles();
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final int noOfFiles = allFiles.length;
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final Vector<FileInputStream> allStreams = new Vector<FileInputStream>();
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for (int i = 0; i < noOfFiles; i++) {
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allStreams.add(new FileInputStream(allFiles[i]));
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}
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final Enumeration<FileInputStream> enu = allStreams.elements();
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final SequenceInputStream sequence = new SequenceInputStream(enu);
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final BufferedReader reader = new BufferedReader(new InputStreamReader(sequence));
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String line = reader.readLine();
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while (line != null) {
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line = reader.readLine();
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}
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reader.close();
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sequence.close();
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}
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@Test
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public void whenReadUTFEncodedFile_thenCorrect() throws IOException {
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final String str = "青空";
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final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
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writer.write(str);
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writer.close();
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final BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("src/test/resources/test_read.txt"), "UTF-8"));
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final String currentLine = reader.readLine();
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reader.close();
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assertEquals(str, currentLine);
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}
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@Test
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public void whenReadFileContentsIntoString_thenCorrect() throws IOException {
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final String str = "Hello world \n Test line \n";
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final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
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writer.write(str);
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writer.close();
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final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/test_read.txt"));
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final StringBuilder builder = new StringBuilder();
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String currentLine = reader.readLine();
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while (currentLine != null) {
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builder.append(currentLine);
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builder.append("\n");
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currentLine = reader.readLine();
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}
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reader.close();
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assertEquals(str, builder.toString());
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}
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@Test
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public void whenReadWithFileChannel_thenCorrect() throws IOException {
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final String str = "Hello world";
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final BufferedWriter writer = new BufferedWriter(new FileWriter("src/test/resources/test_read.txt"));
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writer.write(str);
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writer.close();
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final RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.txt", "r");
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final FileChannel channel = reader.getChannel();
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int bufferSize = 1024;
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if (bufferSize > channel.size())
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bufferSize = (int) channel.size();
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final ByteBuffer buff = ByteBuffer.allocate(bufferSize);
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channel.read(buff);
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buff.flip();
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assertEquals(str, new String(buff.array()));
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channel.close();
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reader.close();
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}
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@Test
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public void whenReadSmallFileJava7_thenCorrect() throws IOException {
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final String str = "Hello world";
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final Path path = Paths.get("src/test/resources/test_read.txt");
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final byte[] strToBytes = str.getBytes();
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Files.write(path, strToBytes);
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final String read = Files.readAllLines(path).get(0);
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assertEquals(str, read);
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}
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@Test
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public void whenReadLargeFileJava7_thenCorrect() throws IOException {
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final String str = "Hello world";
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final Path path = Paths.get("src/test/resources/test_read.txt");
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final byte[] strToBytes = str.getBytes();
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Files.write(path, strToBytes);
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final BufferedReader reader = Files.newBufferedReader(path);
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final String line = reader.readLine();
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assertEquals(str, line);
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}
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}

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