add null check

hutool-core/src/main/java/org/dromara/hutool/core/codec/binary/Base64.java

@@ -43,6 +43,9 @@ public class Base64 {
 	 * @return 编码后的bytes
 	 */
 	public static byte[] encode(final byte[] arr, final boolean lineSep) {
+		if (arr == null) {
+			return null;
+		}
 		return lineSep ?
 			java.util.Base64.getMimeEncoder().encode(arr) :
 			java.util.Base64.getEncoder().encode(arr);
@@ -99,6 +102,9 @@ public class Base64 {
 	 * @return 被加密后的字符串
 	 */
 	public static String encode(final byte[] source) {
+		if (source == null) {
+			return null;
+		}
 		return java.util.Base64.getEncoder().encodeToString(source);
 	}
 
@@ -110,6 +116,9 @@ public class Base64 {
 	 * @since 5.5.2
 	 */
 	public static String encodeWithoutPadding(final byte[] source) {
+		if (source == null) {
+			return null;
+		}
 		return java.util.Base64.getEncoder().withoutPadding().encodeToString(source);
 	}
 
@@ -121,6 +130,9 @@ public class Base64 {
 	 * @since 3.0.6
 	 */
 	public static String encodeUrlSafe(final byte[] source) {
+		if (source == null) {
+			return null;
+		}
 		return java.util.Base64.getUrlEncoder().withoutPadding().encodeToString(source);
 	}
 
@@ -132,6 +144,9 @@ public class Base64 {
 	 * @since 4.0.9
 	 */
 	public static String encode(final InputStream in) {
+		if (in == null) {
+			return null;
+		}
 		return encode(IoUtil.readBytes(in));
 	}
 
@@ -143,6 +158,9 @@ public class Base64 {
 	 * @since 4.0.9
 	 */
 	public static String encodeUrlSafe(final InputStream in) {
+		if (in == null) {
+			return null;
+		}
 		return encodeUrlSafe(IoUtil.readBytes(in));
 	}
 

hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileUtil.java

@@ -1617,6 +1617,9 @@ public class FileUtil extends PathUtil {
 	 * @throws IORuntimeException IO异常
 	 */
 	public static byte[] readBytes(final File file) throws IORuntimeException {
+		if (null == file) {
+			return null;
+		}
 		return readBytes(file.toPath());
 	}
 
@@ -1689,9 +1692,7 @@ public class FileUtil extends PathUtil {
 	 * @since 5.7.10
 	 */
 	public static String readString(final URL url, final Charset charset) throws IORuntimeException {
-		if (url == null) {
+		Assert.notNull(url, "Empty url provided!");
-			throw new NullPointerException("Empty url provided!");
-		}
 
 		InputStream in = null;
 		try {

hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileWrapper.java

@@ -13,7 +13,9 @@
 package org.dromara.hutool.core.io.file;
 
 import org.dromara.hutool.core.func.Wrapper;
+import org.dromara.hutool.core.lang.Assert;
 import org.dromara.hutool.core.util.CharsetUtil;
+import org.dromara.hutool.core.util.ObjUtil;
 
 import java.io.File;
 import java.io.Serializable;
@@ -24,7 +26,6 @@ import java.nio.charset.StandardCharsets;
  * 文件包装器，扩展文件对象
  *
  * @author Looly
- *
  */
 public class FileWrapper implements Wrapper<File>, Serializable {
 	private static final long serialVersionUID = 1L;
@@ -32,24 +33,30 @@ public class FileWrapper implements Wrapper<File>, Serializable{
 	protected File file;
 	protected Charset charset;
 
-	/** 默认编码：UTF-8 */
+	/**
+	 * 默认编码：UTF-8
+	 */
 	public static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
 
 	// ------------------------------------------------------- Constructor start
+
 	/**
 	 * 构造
-	 * @param file 文件
+	 *
-	 * @param charset 编码，使用 {@link CharsetUtil}
+	 * @param file    文件（非{@code null}）
+	 * @param charset 编码，使用 {@link CharsetUtil}，传入{@code null}则使用默认编码{@link #DEFAULT_CHARSET}
 	 */
 	public FileWrapper(final File file, final Charset charset) {
-		this.file = file;
+		this.file = Assert.notNull(file);
-		this.charset = charset;
+		this.charset = ObjUtil.defaultIfNull(charset, DEFAULT_CHARSET);
 	}
 	// ------------------------------------------------------- Constructor end
 
 	// ------------------------------------------------------- Setters and Getters start start
+
 	/**
 	 * 获得文件
+	 *
 	 * @return 文件
 	 */
 	@Override
@@ -59,6 +66,7 @@ public class FileWrapper implements Wrapper<File>, Serializable{
 
 	/**
 	 * 设置文件
+	 *
 	 * @param file 文件
 	 * @return 自身
 	 */
@@ -69,6 +77,7 @@ public class FileWrapper implements Wrapper<File>, Serializable{
 
 	/**
 	 * 获得字符集编码
+	 *
 	 * @return 编码
 	 */
 	public Charset getCharset() {
@@ -77,6 +86,7 @@ public class FileWrapper implements Wrapper<File>, Serializable{
 
 	/**
 	 * 设置字符集编码
+	 *
 	 * @param charset 编码
 	 * @return 自身
 	 */
@@ -88,6 +98,7 @@ public class FileWrapper implements Wrapper<File>, Serializable{
 
 	/**
 	 * 可读的文件大小
+	 *
 	 * @return 大小
 	 */
 	public String readableFileSize() {