BAEL-1308

core-java/src/main/java/com/baeldung/copyfiles/FileCopier.java

@@ -0,0 +1,40 @@
+package com.baeldung.copyfiles;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+
+import org.apache.commons.io.FileUtils;
+
+public class FileCopier {
+	public static File copyWithIO(File original, File copied) throws IOException {
+		try (InputStream in = new BufferedInputStream(new FileInputStream(original));
+				OutputStream out = new BufferedOutputStream(new FileOutputStream(copied))) {
+			byte[] buffer = new byte[1024];
+			int lengthRead;
+			while ((lengthRead = in.read(buffer)) > 0) {
+				out.write(buffer, 0, lengthRead);
+				out.flush();
+			}
+		}
+		return copied;
+	}
+
+	public static Path copyWithNio(Path original, Path copied) throws IOException {
+		Files.copy(original, copied, StandardCopyOption.REPLACE_EXISTING);
+		return copied;
+	}
+
+	public static File copyWithCommonsIO(File original, File copied) throws IOException {
+		FileUtils.copyFile(original, copied);
+		return copied;
+	}
+}

core-java/src/test/java/com/baeldung/copyfiles/FileCopierTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.copyfiles;
+
+import static org.junit.Assert.*;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import org.junit.Test;
+
+public class FileCopierTest {
+
+	@Test
+	public void givenIoAPI_whenCopied_thenCopyExistsWithSameContents() throws IOException {
+		File copied = new File("src/test/resources/copiedWithIo.txt");
+		File original = new File("src/test/resources/original.txt");
+		copied = FileCopier.copyWithIO(original, copied);
+		assertTrue(copied.exists());
+		assertTrue(Files.readAllLines(original.toPath()).equals(Files.readAllLines(copied.toPath())));
+	}
+
+	@Test
+	public void givenCommonsIoAPI_whenCopied_thenCopyExistsWithSameContents() throws IOException {
+		File copied = new File("src/test/resources/copiedWithApacheCommons.txt");
+		File original = new File("src/test/resources/original.txt");
+		copied = FileCopier.copyWithCommonsIO(original, copied);
+		assertTrue(copied.exists());
+		assertTrue(Files.readAllLines(original.toPath()).equals(Files.readAllLines(copied.toPath())));
+	}
+
+	@Test
+	public void givenNIO2_whenCopied_thenCopyExistsWithSameContents() throws IOException {
+		Path copied = Paths.get("src/test/resources/copiedWithNio.txt");
+		Path original = Paths.get("src/test/resources/original.txt");
+		copied = FileCopier.copyWithNio(original, copied);
+		assertTrue(Files.exists(copied));
+		assertTrue(Files.readAllLines(original).equals(Files.readAllLines(copied)));
+	}
+}