mimeType, extension 수정

src/main/java/cokr/xit/base/file/FileInfo.java

@@ -430,7 +430,7 @@ public class FileInfo extends AbstractEntity {
 	 * @return mime type
 	 */
 	public String getMimeType() {
-		return Assert.ifEmpty(mimeType, mimeType = "application/octet-stream");
+		return Assert.ifEmpty(mimeType, () -> mimeType = "application/octet-stream");
 	}
 
 	/**mime type을 설정한다.
@@ -444,7 +444,7 @@ public class FileInfo extends AbstractEntity {
 	 * @return 확장자
 	 */
 	public String getExtension() {
-		return Assert.ifEmpty(extension, extension = extension(name));
+		return Assert.ifEmpty(extension, () -> extension = extension(name));
 	}
 
 	/**확장자를 설정한다.