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

JAVA-112 merge duplicate read file articles

core-java-modules/core-java-io/README.md

@@ -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)

core-java-modules/core-java-io/src/test/java/com/baeldung/readfile/FileOperationsManualTest.java

@@ -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());
-    }
-}

core-java-modules/core-java-io/src/test/java/com/baeldung/readfile/JavaReadFromFileUnitTest.java

@@ -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();
+    }
+
 }

core-java-modules/core-java-io/src/test/resources/fileTest.txt

@@ -1 +1 @@
-Hello World from fileTest.txt!!!
+Hello, world!

core-java-modules/core-java-io/src/test/resources/test_read1.in

@@ -1 +0,0 @@
-Hello world 1

core-java-modules/core-java-io/src/test/resources/test_read2.in

@@ -1 +0,0 @@
-2,3 4

core-java-modules/core-java-io/src/test/resources/test_read8.in

@@ -1,2 +0,0 @@
-Hello world 
- Test line