Add file copy examples

src/main/java/io/javaalmanac/snippets/io/CopyFiles.java

@@ -0,0 +1,60 @@
+package io.javaalmanac.snippets.io;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
+import java.util.HexFormat;
+
+/**
+ * The {@link java.nio.file.Files} class offers a couple of convenience methods
+ * to copy data between files, {@link java.io.InputStream}s and
+ * {@link java.io.OutputStream}s. Also streams can be directly transferred with
+ * {@link java.io.InputStream#transferTo(java.io.OutputStream)}. Many Java
+ * idioms with temporary buffers shuffling data chunks in `while` loops are
+ * obsolete nowadays.
+ * 
+ * @title Copy Files and IO Streams
+ * @category api.io
+ * @since 9
+ */
+public class CopyFiles {
+
+	static final HexFormat HEX = HexFormat.of();
+
+	static final byte[] TEST_CONTENT = HEX.parseHex("cafebabe");
+
+	public static void main(String... args) throws IOException {
+
+		var srcfile = Files.createTempFile("CopyFiles", ".txt");
+		var dstfile = Files.createTempFile("CopyFiles", ".txt");
+		Files.write(srcfile, TEST_CONTENT);
+
+		// Directly copy files
+		Files.copy(srcfile, dstfile, StandardCopyOption.REPLACE_EXISTING);
+
+		System.out.println(HEX.formatHex(Files.readAllBytes(dstfile)));
+
+		// Copy data from InputStream to a file:
+		var in = new ByteArrayInputStream(TEST_CONTENT);
+		Files.copy(in, dstfile, StandardCopyOption.REPLACE_EXISTING);
+
+		System.out.println(HEX.formatHex(Files.readAllBytes(dstfile)));
+
+		// Copy the file content to an OutputStream:
+		var out = new ByteArrayOutputStream();
+		Files.copy(srcfile, out);
+
+		System.out.println(HEX.formatHex(out.toByteArray()));
+
+		// Copy content from an InputStream to an OutputStream:
+		in = new ByteArrayInputStream(TEST_CONTENT);
+		out = new ByteArrayOutputStream();
+		in.transferTo(out);
+
+		System.out.println(HEX.formatHex(out.toByteArray()));
+
+	}
+
+}

todos.md

@@ -2,8 +2,6 @@
 
 ## io
 
-* Copy Files
-* Copy IO Streams
 * traverse file system structure
 
 ## lang
@@ -27,6 +25,7 @@
 * Aggregating Objects
 * Grouping Objects
 * Avoiding null (Empty collections, Optional)
+* Regex/Matcher
 
 ## security