BAEL-3214 | Java FileWriter class code - 2

Nikunj Gandhi · Nikunj Gandhi · commit 31be377141a5 · 2019-09-15T13:17:48.000-04:00
diff --git a/core-java-modules/core-java-io-2/src/main/java/com/baeldung/filewriter/FileWriterExample.java b/core-java-modules/core-java-io-2/src/main/java/com/baeldung/filewriter/FileWriterExample.java
@@ -0,0 +1,37 @@
+package com.baeldung.filewriter;
+
+import java.io.BufferedWriter;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.List;
+
+public class FileWriterExample {
+
+    public void writeString(String fileName, String strToWrite) throws IOException {
+        try (FileWriter fileWriter = new FileWriter(fileName)) {
+            fileWriter.write(strToWrite);
+        }
+    }
+
+    public void appendString(String fileName, String stringToAppend) throws IOException {
+        try (FileWriter fileWriter = new FileWriter(fileName, true)) {
+            fileWriter.append(stringToAppend);
+        }
+    }
+
+    public void writeCharArray(String fileName, char[] charArrToWrite) throws IOException {
+        try (FileWriter fileWriter = new FileWriter(fileName)) {
+            fileWriter.write(charArrToWrite);
+        }
+    }
+
+    public void writeWithBufferedWriter(String fileName, List<String> stringsToWrite) throws IOException {
+        try (FileWriter fileWriter = new FileWriter(fileName); BufferedWriter bufferedWriter = new BufferedWriter(fileWriter)) {
+            for (String stringToWrite : stringsToWrite) {
+                bufferedWriter.write(stringToWrite);
+            }
+        }
+
+    }
+
+}
diff --git a/core-java-modules/core-java-io-2/src/test/java/com/baeldung/filewriter/FileWriterExampleTest.java b/core-java-modules/core-java-io-2/src/test/java/com/baeldung/filewriter/FileWriterExampleTest.java
diff --git a/core-java-modules/core-java-io-2/src/test/java/com/baeldung/filewriter/FileWriterExampleUnitTest.java b/core-java-modules/core-java-io-2/src/test/java/com/baeldung/filewriter/FileWriterExampleUnitTest.java
@@ -0,0 +1,57 @@
+package com.baeldung.filewriter;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.IntStream;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class FileWriterExampleUnitTest {
+
+    private static final String FILE_NAME = "src/test/resources/FileWriterTest.txt";
+    private static final String STRING_TO_WRITE = "Hello Folks!";
+    private static final String STRING_TO_APPEND = "Hello Folks Again!";
+    private static final char[] CHAR_ARRAY_TO_WRITE = STRING_TO_WRITE.toCharArray();
+
+    private FileWriterExample fileWriterExample = new FileWriterExample();
+
+    @After
+    public void tearDown() throws IOException {
+        Files.delete(Path.of(FILE_NAME));
+    }
+
+    @Test
+    public void testWriteString() throws IOException {
+        fileWriterExample.writeString(FILE_NAME, STRING_TO_WRITE);
+        Assert.assertEquals(STRING_TO_WRITE, new String(Files.readAllBytes(Path.of(FILE_NAME))));
+    }
+
+    @Test
+    public void testAppendString() throws IOException {
+        fileWriterExample.writeString(FILE_NAME, STRING_TO_WRITE);
+        fileWriterExample.appendString(FILE_NAME, STRING_TO_APPEND);
+        Assert.assertEquals(STRING_TO_WRITE + STRING_TO_APPEND, new String(Files.readAllBytes(Path.of(FILE_NAME))));
+    }
+
+    @Test
+    public void testWriteCharArray() throws IOException {
+        fileWriterExample.writeCharArray(FILE_NAME, CHAR_ARRAY_TO_WRITE);
+        Assert.assertEquals(STRING_TO_WRITE, new String(Files.readAllBytes(Path.of(FILE_NAME))));
+    }
+    
+    @Test
+    public void testWriteWithBufferedWriter() throws IOException{
+        final List<String> stringsToWrite = new ArrayList<>();
+        for(int i=0 ; i < 10000;i++) {
+            stringsToWrite.add("Random string "+i);
+        }
+        fileWriterExample.writeWithBufferedWriter(FILE_NAME, stringsToWrite);
+        Assert.assertNotNull(new String(Files.readAllBytes(Path.of(FILE_NAME))));
+    }
+}
