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Merge pull request #8717 from Maiklins/JAVA-112-merge-duplicate-read-file-articles

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JAVA-112 merge duplicate read file articles
This commit is contained in:
Loredana Crusoveanu 2020-02-16 21:32:41 +02:00 committed by GitHub
commit f1e1ca8dcf
10 changed files with 151 additions and 193 deletions
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2
core-java-modules/core-java-io/README.md
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@ -3,7 +3,7 @@
This module contains articles about core Java input and output (IO)
### Relevant Articles:
- [How to Read a File in Java](https://www.baeldung.com/reading-file-in-java)
- [Java – Read from File](https://www.baeldung.com/java-read-file)
- [Read a File into an ArrayList](https://www.baeldung.com/java-file-to-arraylist)
- [Java – Directory Size](https://www.baeldung.com/java-folder-size)
- [File Size in Java](https://www.baeldung.com/java-file-size)

134
core-java-modules/core-java-io/src/test/java/com/baeldung/readfile/FileOperationsManualTest.java
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@ -1,134 +0,0 @@
package com.baeldung.readfile;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.hamcrest.CoreMatchers;
import org.hamcrest.Matchers;
import org.junit.Test;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThat;
public class FileOperationsManualTest {
@Test
public void givenFileName_whenUsingClassloader_thenFileData() throws IOException {
String expectedData = "Hello World from fileTest.txt!!!";
ClassLoader classLoader = getClass().getClassLoader();
File file = new File(classLoader.getResource("fileTest.txt").getFile());
InputStream inputStream = new FileInputStream(file);
String data = readFromInputStream(inputStream);
assertEquals(expectedData, data.trim());
}
@Test
public void givenFileNameAsAbsolutePath_whenUsingClasspath_thenFileData() throws IOException {
String expectedData = "Hello World from fileTest.txt!!!";
Class clazz = FileOperationsManualTest.class;
InputStream inputStream = clazz.getResourceAsStream("/fileTest.txt");
String data = readFromInputStream(inputStream);
assertEquals(expectedData, data.trim());
}
@Test
public void givenFileName_whenUsingJarFile_thenFileData() throws IOException {
String expectedData = "MIT License";
Class clazz = Matchers.class;
InputStream inputStream = clazz.getResourceAsStream("/LICENSE.txt");
String data = readFromInputStream(inputStream);
assertThat(data.trim(), CoreMatchers.containsString(expectedData));
}
@Test
public void givenURLName_whenUsingURL_thenFileData() throws IOException {
String expectedData = "Example Domain";
URL urlObject = new URL("http://www.example.com/");
URLConnection urlConnection = urlObject.openConnection();
InputStream inputStream = urlConnection.getInputStream();
String data = readFromInputStream(inputStream);
assertThat(data.trim(), CoreMatchers.containsString(expectedData));
}
@Test
public void givenFileName_whenUsingFileUtils_thenFileData() throws IOException {
String expectedData = "Hello World from fileTest.txt!!!";
ClassLoader classLoader = getClass().getClassLoader();
File file = new File(classLoader.getResource("fileTest.txt").getFile());
String data = FileUtils.readFileToString(file, "UTF-8");
assertEquals(expectedData, data.trim());
}
@Test
public void givenFilePath_whenUsingFilesReadAllBytes_thenFileData() throws IOException, URISyntaxException {
String expectedData = "Hello World from fileTest.txt!!!";
Path path = Paths.get(getClass().getClassLoader().getResource("fileTest.txt").toURI());
byte[] fileBytes = Files.readAllBytes(path);
String data = new String(fileBytes);
assertEquals(expectedData, data.trim());
}
@Test
public void givenFilePath_whenUsingFilesLines_thenFileData() throws IOException, URISyntaxException {
String expectedData = "Hello World from fileTest.txt!!!";
Path path = Paths.get(getClass().getClassLoader().getResource("fileTest.txt").toURI());
Stream<String> lines = Files.lines(path);
String data = lines.collect(Collectors.joining("\n"));
lines.close();
assertEquals(expectedData, data.trim());
}
private String readFromInputStream(InputStream inputStream) throws IOException {
StringBuilder resultStringBuilder = new StringBuilder();
try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream))) {
String line;
while ((line = bufferedReader.readLine()) != null) {
resultStringBuilder.append(line).append("\n");
}
}
return resultStringBuilder.toString();
}
@Test
public void givenFileName_whenUsingIOUtils_thenFileData() throws IOException {
String expectedData = "This is a content of the file";
FileInputStream fis = new FileInputStream("src/test/resources/fileToRead.txt");
String data = IOUtils.toString(fis, "UTF-8");
assertEquals(expectedData, data.trim());
}
}

202
core-java-modules/core-java-io/src/test/java/com/baeldung/readfile/JavaReadFromFileUnitTest.java
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@ -1,11 +1,15 @@
package com.baeldung.readfile;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.hamcrest.CoreMatchers;
import org.hamcrest.Matchers;
import org.junit.Test;
import org.junit.Ignore;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.*;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.charset.Charset;
@ -13,55 +17,148 @@ import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Scanner;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
public class JavaReadFromFileUnitTest {
private static final Logger LOG = LoggerFactory.getLogger(JavaReadFromFileUnitTest.class);
@Test
public void whenReadWithBufferedReader_thenCorrect() throws IOException {
final String expected_value = "Hello world";
final String expected_value = "Hello, world!";
final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/test_read.in"));
final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/fileTest.txt"));
final String currentLine = reader.readLine();
reader.close();
assertEquals(expected_value, currentLine);
}
@Test
public void givenFileName_whenUsingClassloader_thenFileData() throws IOException {
String expectedData = "Hello, world!";
ClassLoader classLoader = getClass().getClassLoader();
File file = new File(classLoader.getResource("fileTest.txt").getFile());
InputStream inputStream = new FileInputStream(file);
String data = readFromInputStream(inputStream);
assertEquals(expectedData, data.trim());
}
@Test
public void givenFileNameAsAbsolutePath_whenUsingClasspath_thenFileData() throws IOException {
String expectedData = "Hello, world!";
Class clazz = JavaReadFromFileUnitTest.class;
InputStream inputStream = clazz.getResourceAsStream("/fileTest.txt");
String data = readFromInputStream(inputStream);
assertEquals(expectedData, data.trim());
}
@Test
public void givenFileName_whenUsingJarFile_thenFileData() throws IOException {
String expectedData = "BSD License";
Class clazz = Matchers.class;
InputStream inputStream = clazz.getResourceAsStream("/LICENSE.txt");
String data = readFromInputStream(inputStream);
assertThat(data.trim(), CoreMatchers.containsString(expectedData));
}
@Test
public void givenURLName_whenUsingURL_thenFileData() throws IOException {
String expectedData = "Example Domain";
URL urlObject = new URL("http://www.example.com/");
URLConnection urlConnection = urlObject.openConnection();
InputStream inputStream = urlConnection.getInputStream();
String data = readFromInputStream(inputStream);
assertThat(data.trim(), CoreMatchers.containsString(expectedData));
}
@Test
public void givenFileName_whenUsingFileUtils_thenFileData() throws IOException {
String expectedData = "Hello, world!";
ClassLoader classLoader = getClass().getClassLoader();
File file = new File(classLoader.getResource("fileTest.txt").getFile());
String data = FileUtils.readFileToString(file, "UTF-8");
assertEquals(expectedData, data.trim());
}
@Test
public void givenFilePath_whenUsingFilesReadAllBytes_thenFileData() throws IOException, URISyntaxException {
String expectedData = "Hello, world!";
Path path = Paths.get(getClass().getClassLoader().getResource("fileTest.txt").toURI());
byte[] fileBytes = Files.readAllBytes(path);
String data = new String(fileBytes);
assertEquals(expectedData, data.trim());
}
@Test
public void givenFilePath_whenUsingFilesLines_thenFileData() throws IOException, URISyntaxException {
String expectedData = "Hello, world!";
Path path = Paths.get(getClass().getClassLoader().getResource("fileTest.txt").toURI());
Stream<String> lines = Files.lines(path);
String data = lines.collect(Collectors.joining("\n"));
lines.close();
assertEquals(expectedData, data.trim());
}
@Test
public void givenFileName_whenUsingIOUtils_thenFileData() throws IOException {
String expectedData = "Hello, world!";
FileInputStream fis = new FileInputStream("src/test/resources/fileTest.txt");
String data = IOUtils.toString(fis, "UTF-8");
assertEquals(expectedData, data.trim());
}
@Test
public void whenReadWithScanner_thenCorrect() throws IOException {
final Scanner scanner = new Scanner(new File("src/test/resources/test_read1.in"));
final Scanner scanner = new Scanner(new File("src/test/resources/fileTest.txt"));
scanner.useDelimiter(" ");
assertTrue(scanner.hasNext());
assertEquals("Hello", scanner.next());
assertEquals("world", scanner.next());
assertEquals(1, scanner.nextInt());
assertEquals("Hello,", scanner.next());
assertEquals("world!", scanner.next());
scanner.close();
}
@Test
public void whenReadWithScannerTwoDelimiters_thenCorrect() throws IOException {
final Scanner scanner = new Scanner(new File("src/test/resources/test_read2.in"));
scanner.useDelimiter(",| ");
final Scanner scanner = new Scanner(new File("src/test/resources/fileTest.txt"));
scanner.useDelimiter("\\s|,");
assertTrue(scanner.hasNextInt());
assertEquals(2, scanner.nextInt());
assertEquals(3, scanner.nextInt());
assertEquals(4, scanner.nextInt());
assertTrue(scanner.hasNext());
assertEquals("Hello", scanner.next());
assertEquals("", scanner.next());
assertEquals("world!", scanner.next());
scanner.close();
}
@Test
public void whenReadWithStreamTokenizer_thenCorrectTokens() throws IOException {
final FileReader reader = new FileReader("src/test/resources/test_read3.in");
final FileReader reader = new FileReader("src/test/resources/fileTestTokenizer.txt");
final StreamTokenizer tokenizer = new StreamTokenizer(reader);
tokenizer.nextToken();
@ -78,49 +175,36 @@ public class JavaReadFromFileUnitTest {
@Test
public void whenReadWithDataInputStream_thenCorrect() throws IOException {
final String expected_value = "Hello";
String expectedValue = "Hello, world!";
String file ="src/test/resources/fileTest.txt";
String result;
final DataInputStream reader = new DataInputStream(new FileInputStream("src/test/resources/test_read4.in"));
result = reader.readUTF();
reader.close();
String result = null;
assertEquals(expected_value, result);
}
DataInputStream reader = new DataInputStream(new FileInputStream(file));
int nBytesToRead = reader.available();
if(nBytesToRead > 0) {
byte[] bytes = new byte[nBytesToRead];
reader.read(bytes);
result = new String(bytes);
}
public void whenReadTwoFilesWithSequenceInputStream_thenCorrect() throws IOException {
final int expected_value1 = 2000;
final int expected_value2 = 5000;
final FileInputStream stream1 = new FileInputStream("src/test/resources/test_read5.in");
final FileInputStream stream2 = new FileInputStream("src/test/resources/test_read6.in");
final SequenceInputStream sequence = new SequenceInputStream(stream1, stream2);
final DataInputStream reader = new DataInputStream(sequence);
assertEquals(expected_value1, reader.readInt());
assertEquals(expected_value2, reader.readInt());
reader.close();
stream2.close();
assertEquals(expectedValue, result);
}
@Test
@Ignore // TODO
public void whenReadUTFEncodedFile_thenCorrect() throws IOException {
final String expected_value = "青空";
final BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("src/test/resources/test_read7.in"), "UTF-8"));
final BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("src/test/resources/fileTestUtf8.txt"), "UTF-8"));
final String currentLine = reader.readLine();
reader.close();
LOG.debug(currentLine);
assertEquals(expected_value, currentLine);
}
@Test
public void whenReadFileContentsIntoString_thenCorrect() throws IOException {
final String expected_value = "Hello world \n Test line \n";
final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/test_read8.in"));
final String expected_value = "Hello, world!\n";
final BufferedReader reader = new BufferedReader(new FileReader("src/test/resources/fileTest.txt"));
final StringBuilder builder = new StringBuilder();
String currentLine = reader.readLine();
while (currentLine != null) {
@ -136,8 +220,8 @@ public class JavaReadFromFileUnitTest {
@Test
public void whenReadWithFileChannel_thenCorrect() throws IOException {
final String expected_value = "Hello world";
final RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r");
final String expected_value = "Hello, world!";
final RandomAccessFile reader = new RandomAccessFile("src/test/resources/fileTest.txt", "r");
final FileChannel channel = reader.getChannel();
int bufferSize = 1024;
@ -154,8 +238,8 @@ public class JavaReadFromFileUnitTest {
@Test
public void whenReadSmallFileJava7_thenCorrect() throws IOException {
final String expected_value = "Hello world";
final Path path = Paths.get("src/test/resources/test_read.in");
final String expected_value = "Hello, world!";
final Path path = Paths.get("src/test/resources/fileTest.txt");
final String read = Files.readAllLines(path, Charset.defaultCharset()).get(0);
assertEquals(expected_value, read);
@ -163,12 +247,24 @@ public class JavaReadFromFileUnitTest {
@Test
public void whenReadLargeFileJava7_thenCorrect() throws IOException {
final String expected_value = "Hello world";
final String expected_value = "Hello, world!";
final Path path = Paths.get("src/test/resources/test_read.in");
final Path path = Paths.get("src/test/resources/fileTest.txt");
final BufferedReader reader = Files.newBufferedReader(path, Charset.defaultCharset());
final String line = reader.readLine();
assertEquals(expected_value, line);
}
private String readFromInputStream(InputStream inputStream) throws IOException {
StringBuilder resultStringBuilder = new StringBuilder();
try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream))) {
String line;
while ((line = bufferedReader.readLine()) != null) {
resultStringBuilder.append(line).append("\n");
}
}
return resultStringBuilder.toString();
}
}

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core-java-modules/core-java-io/src/test/resources/fileTest.txt
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@ -1 +1 @@
Hello World from fileTest.txt!!!
Hello, world!

0
core-java-modules/core-java-io/src/test/resources/test_read3.in → core-java-modules/core-java-io/src/test/resources/fileTestTokenizer.txt
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0
core-java-modules/core-java-io/src/test/resources/test_read7.in → core-java-modules/core-java-io/src/test/resources/fileTestUtf8.txt
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1
core-java-modules/core-java-io/src/test/resources/test_read1.in
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@ -1 +0,0 @@
Hello world 1

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core-java-modules/core-java-io/src/test/resources/test_read2.in
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@ -1 +0,0 @@
2,3 4

BIN
core-java-modules/core-java-io/src/test/resources/test_read4.in
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core-java-modules/core-java-io/src/test/resources/test_read8.in
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@ -1,2 +0,0 @@
Hello world
Test line