fix 更新配置失效问题

src/main/java/com/yutou/bilibili/Controllers/VideoFileController.java

@@ -21,6 +21,7 @@ import org.springframework.web.bind.annotation.ResponseBody;
 
 import java.io.ByteArrayOutputStream;
 import java.io.File;
+import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
 import java.net.URLDecoder;
@@ -52,7 +53,13 @@ public class VideoFileController {
         url = URLDecoder.decode(url, StandardCharsets.UTF_8);
         String encode = AppTools.getMD5(url);
         File img = new File("cache" + File.separator + "image" + File.separator + encode);
-        if (img.exists()) {
+        int length;
+        try {
+            length = new URL(url).openConnection().getContentLength();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        if (img.exists()&&length==img.length()) {
             return Tools.getFile(img);
         }
         if (!img.getParentFile().exists()) {