feat(devkit-core): added Base64Util

Base64Util can encode any string to Base64 string or decode any Base64
string.

dev-utils/src/main/java/cn/org/codecrafters/devutils/Base64Util.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2023 CodeCraftersCN.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cn.org.codecrafters.devutils;
+
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+
+/**
+ * Utility class for Base64 encoding and decoding of strings.
+ * <p>
+ * The {@code Base64Util} class provides static methods to encode and decode strings using Base64 encoding.
+ * It utilizes the {@link Base64} class from the Java standard library for performing the encoding and decoding operations.
+ * This utility class offers convenient methods to encode and decode strings with different character sets.
+ * <p>
+ * This class is designed as a final class with a private constructor to prevent instantiation.
+ * All methods in this class are static, allowing easy access to the Base64 encoding and decoding functionality.
+ * <p>
+ * Example usage:
+ * <pre>{@code
+ * String original = "Hello, World!";
+ *
+ * // Encode the string using UTF-8 charset
+ * String encoded = Base64Util.encode(original);
+ * System.out.println("Encoded string: " + encoded);
+ *
+ * // Decode the encoded string using UTF-8 charset
+ * String decoded = Base64Util.decode(encoded);
+ * System.out.println("Decoded string: " + decoded);
+ * }</pre>
+ * <p>
+ * <b>Note:</b> This utility class uses the default charset (UTF-8) if no specific charset is provided.
+ * It is recommended to specify the charset explicitly to ensure consistent encoding and decoding.
+ * <p>
+ * <b>Thread Safety:</b> The methods in this class are thread-safe.
+ * Multiple threads can safely use the methods for encoding and decoding strings simultaneously.
+ *
+ * @since 10 Jul 2023
+ * @author Zihlu Wang
+ * @version 1.0.0
+ */
+public final class Base64Util {
+
+    /**
+     * Private constructor to prevent instantiation of the class.
+     */
+    private Base64Util() {
+    }
+
+    /**
+     * Encodes the given string using the specified charset.
+     *
+     * @param value   the string to be encoded
+     * @param charset the charset to be used for encoding
+     * @return the Base64 encoded string
+     */
+    public static String encode(String value, Charset charset) {
+        var encoder = Base64.getEncoder();
+        var encoded = encoder.encode(value.getBytes(charset));
+
+        return new String(encoded);
+    }
+
+    /**
+     * Encodes the given string using the default UTF-8 charset.
+     *
+     * @param value the string to be encoded
+     * @return the Base64 encoded string
+     */
+    public static String encode(String value) {
+        return encode(value, StandardCharsets.UTF_8);
+    }
+
+    /**
+     * Decodes the given Base64 encoded string using the specified charset.
+     *
+     * @param value   the Base64 encoded string to be decoded
+     * @param charset the charset to be used for decoding
+     * @return the decoded string
+     */
+    public static String decode(String value, Charset charset) {
+        var decoder = Base64.getDecoder();
+        var decoded = decoder.decode(value.getBytes(charset));
+
+        return new String(decoded);
+    }
+
+    /**
+     * Decodes the given Base64 encoded string using the default UTF-8 charset.
+     *
+     * @param value the Base64 encoded string to be decoded
+     * @return the decoded string
+     */
+    public static String decode(String value) {
+        return decode(value, StandardCharsets.UTF_8);
+    }
+
+}