升级JDK到21

src/main/java/com/ai/da/controller/LibraryController.java

@@ -24,8 +24,8 @@ import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
 import org.springframework.web.multipart.MultipartFile;
 
-import javax.annotation.Resource;
-import javax.validation.Valid;
+import jakarta.annotation.Resource;
+import jakarta.validation.Valid;
 import java.io.File;
 import java.text.ParseException;
 import java.util.*;