add method

CHANGELOG.md

@@ -21,6 +21,7 @@
 * 【core   】     新增MetroHash(pr#532@Gitee)
 * 【core   】     SpringUtil增加publishEvent重载(pr#2139@Github)
 * 【core   】     DateUtil增加rangeContains、rangeNotContains(pr#537@Gitee)
+* 【core   】     Resource增加isModified默认方法
 
 ### 🐞Bug修复
 * 【core   】     修复ChineseDate农历获取正月出现数组越界BUG（issue#2112@Github）

hutool-core/src/main/java/cn/hutool/core/io/resource/FileResource.java

@@ -20,6 +20,7 @@ public class FileResource implements Resource, Serializable {
 	private static final long serialVersionUID = 1L;
 
 	private final File file;
+	private final long lastModified;
 	private final String name;
 
 	// ----------------------------------------------------------------------- Constructor start
@@ -60,6 +61,7 @@ public class FileResource implements Resource, Serializable {
 	public FileResource(File file, String fileName) {
 		Assert.notNull(file, "File must be not null !");
 		this.file = file;
+		this.lastModified = file.lastModified();
 		this.name = ObjectUtil.defaultIfNull(fileName, file::getName);
 	}
 
@@ -89,6 +91,11 @@ public class FileResource implements Resource, Serializable {
 		return this.file;
 	}
 
+	@Override
+	public boolean isModified() {
+		return this.lastModified != file.lastModified();
+	}
+
 	/**
 	 * 返回路径
 	 * @return 返回URL路径

hutool-core/src/main/java/cn/hutool/core/io/resource/MultiResource.java

@@ -63,6 +63,11 @@ public class MultiResource implements Resource, Iterable<Resource>, Iterator<Res
 		return resources.get(cursor).getStream();
 	}
 
+	@Override
+	public boolean isModified() {
+		return resources.get(cursor).isModified();
+	}
+
 	@Override
 	public BufferedReader getReader(Charset charset) {
 		return resources.get(cursor).getReader(charset);

hutool-core/src/main/java/cn/hutool/core/io/resource/Resource.java

@@ -53,6 +53,17 @@ public interface Resource {
 	 */
 	InputStream getStream();
 
+	/**
+	 * 检查资源是否变更<br>
+	 * 一般用于文件类资源，检查文件是否被修改过。
+	 *
+	 * @return 是否变更
+	 * @since 5.7.21
+	 */
+	default boolean isModified(){
+		return false;
+	}
+
 	/**
 	 * 将资源内容写出到流，不关闭输出流，但是关闭资源流
 	 *

hutool-core/src/main/java/cn/hutool/core/io/resource/UrlResource.java

@@ -18,6 +18,7 @@ public class UrlResource implements Resource, Serializable{
 	private static final long serialVersionUID = 1L;
 
 	protected URL url;
+	private long lastModified = 0;
 	protected String name;
 
 	//-------------------------------------------------------------------------------------- Constructor start
@@ -36,6 +37,9 @@ public class UrlResource implements Resource, Serializable{
 	 */
 	public UrlResource(URL url, String name) {
 		this.url = url;
+		if(null != url && URLUtil.isFileURL(url)){
+			this.lastModified = FileUtil.file(url).lastModified();
+		}
 		this.name = ObjectUtil.defaultIfNull(name, () -> (null != url ? FileUtil.getName(url.getPath()) : null));
 	}
 
@@ -68,6 +72,12 @@ public class UrlResource implements Resource, Serializable{
 		return URLUtil.getStream(url);
 	}
 
+	@Override
+	public boolean isModified() {
+		// lastModified == 0表示此资源非文件资源
+		return (0 != this.lastModified) && this.lastModified != getFile().lastModified();
+	}
+
 	/**
 	 * 获得File
 	 * @return {@link File}

hutool-core/src/main/java/cn/hutool/core/util/URLUtil.java

@@ -461,6 +461,7 @@ public class URLUtil extends URLEncodeUtil {
 	 * @since 3.0.9
 	 */
 	public static boolean isFileURL(URL url) {
+		Assert.notNull(url, "URL must be not null");
 		String protocol = url.getProtocol();
 		return (URL_PROTOCOL_FILE.equals(protocol) || //
 				URL_PROTOCOL_VFSFILE.equals(protocol) || //
@@ -474,6 +475,7 @@ public class URLUtil extends URLEncodeUtil {
 	 * @return 是否为jar包URL
 	 */
 	public static boolean isJarURL(URL url) {
+		Assert.notNull(url, "URL must be not null");
 		final String protocol = url.getProtocol();
 		return (URL_PROTOCOL_JAR.equals(protocol) || //
 				URL_PROTOCOL_ZIP.equals(protocol) || //
@@ -489,6 +491,7 @@ public class URLUtil extends URLEncodeUtil {
 	 * @since 4.1
 	 */
 	public static boolean isJarFileURL(URL url) {
+		Assert.notNull(url, "URL must be not null");
 		return (URL_PROTOCOL_FILE.equals(url.getProtocol()) && //
 				url.getPath().toLowerCase().endsWith(FileUtil.JAR_FILE_EXT));
 	}
@@ -501,7 +504,7 @@ public class URLUtil extends URLEncodeUtil {
 	 * @since 3.2.1
 	 */
 	public static InputStream getStream(URL url) {
-		Assert.notNull(url);
+		Assert.notNull(url, "URL must be not null");
 		try {
 			return url.openStream();
 		} catch (IOException e) {