BAEL-1308 - Copy a File with Java (#3000)

* Create Student.java

* Create ApplicationContextTestBeanInjection.java

* Update Student.java

* added tests

added tests

* BAEL-1308

part 1

* Create test_stream.txt

* Create test_files.txt

* Create test_channel.txt

* Create test_apache.txt

* Create test.txt

* Delete test.txt

* Create readme.txt

* Delete Student.java

* Delete StudentInjectionTest.java

* Delete ApplicationContextTestBeanInjection.java

core-java/src/main/java/com/baeldung/stream/FileCopy.java

@@ -0,0 +1,48 @@
+package com.baeldung.stream;
+
+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.channels.FileChannel;
+import java.nio.file.Files;
+
+import org.apache.commons.io.FileUtils;
+
+public class FileCopy {
+
+    public static void copyFileUsingStream(File source, File dest) throws IOException {
+        InputStream is = null;
+        OutputStream os = null;
+        is = new FileInputStream(source);
+        os = new FileOutputStream(dest);
+        byte[] buffer = new byte[1024];
+        int length;
+        while ((length = is.read(buffer)) > 0) {
+            os.write(buffer, 0, length);
+        }
+        is.close();
+        os.close();
+    }
+
+    public static void copyFileUsingChannel(File source, File dest) throws IOException {
+        FileChannel sourceChannel = null;
+        FileChannel destChannel = null;
+        sourceChannel = new FileInputStream(source).getChannel();
+        destChannel = new FileOutputStream(dest).getChannel();
+        destChannel.transferFrom(sourceChannel, 0, sourceChannel.size());
+        sourceChannel.close();
+        destChannel.close();
+    }
+
+    public static void copyFileUsingApacheCommonsIO(File source, File dest) throws IOException {
+        FileUtils.copyFile(source, dest);
+    }
+
+    public static void copyFileUsingJavaFiles(File source, File dest) throws IOException {
+        Files.copy(source.toPath(), dest.toPath());
+    }
+
+}

core-java/src/test/java/com/baeldung/stream/FileCopyTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.stream;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.junit.Test;
+
+public class FileCopyTest {
+
+    @Test
+    public void whenUsingStream_thenCopyFile() throws IOException {
+        File src = new File("src" + File.separator + "test" + File.separator + "resources" + File.separator + "copyTest" + File.separator + "src" + File.separator + "test_stream.txt");
+        File dest = new File("src" + File.separator + "test" + File.separator + "resources" + File.separator + "copyTest" + File.separator + "dest" + File.separator + "test_stream.txt");
+        FileCopy.copyFileUsingStream(src, dest);
+        assertTrue(dest.exists());
+        dest.delete();
+    }
+
+    @Test
+    public void whenUsingFiles_thenCopyFile() throws IOException {
+        File src = new File("src" + File.separator + "test" + File.separator + "resources" + File.separator + "copyTest" + File.separator + "src" + File.separator + "test_files.txt");
+        File dest = new File("src" + File.separator + "test" + File.separator + "resources" + File.separator + "copyTest" + File.separator + "dest" + File.separator + "test_files.txt");
+        FileCopy.copyFileUsingJavaFiles(src, dest);
+        assertTrue(dest.exists());
+        dest.delete();
+    }
+
+    @Test
+    public void whenUsingChannel_thenCopyFile() throws IOException {
+        File src = new File("src" + File.separator + "test" + File.separator + "resources" + File.separator + "copyTest" + File.separator + "src" + File.separator + "test_channel.txt");
+        File dest = new File("src" + File.separator + "test" + File.separator + "resources" + File.separator + "copyTest" + File.separator + "dest" + File.separator + "test_channel.txt");
+        FileCopy.copyFileUsingChannel(src, dest);
+        assertTrue(dest.exists());
+        dest.delete();
+    }
+
+    @Test
+    public void whenUsingApache_thenCopyFile() throws IOException {
+        File src = new File("src" + File.separator + "test" + File.separator + "resources" + File.separator + "copyTest" + File.separator + "src" + File.separator + "test_apache.txt");
+        File dest = new File("src" + File.separator + "test" + File.separator + "resources" + File.separator + "copyTest" + File.separator + "dest" + File.separator + "test_apache.txt");
+        FileCopy.copyFileUsingApacheCommonsIO(src, dest);
+        assertTrue(dest.exists());
+        dest.delete();
+    }
+}

core-java/src/test/resources/copyTest/dest/readme.txt

@@ -0,0 +1,2 @@
+files will be copied here and then deleted
+remove `file.delete()` to see the files here 

core-java/src/test/resources/copyTest/src/test_apache.txt

@@ -0,0 +1 @@
+apache

core-java/src/test/resources/copyTest/src/test_channel.txt

@@ -0,0 +1 @@
+channel

core-java/src/test/resources/copyTest/src/test_files.txt

@@ -0,0 +1 @@
+files

core-java/src/test/resources/copyTest/src/test_stream.txt

@@ -0,0 +1 @@
+stream