org.springframework.beans.TypeMismatchException：无法将类型“ java.lang.String”的值转换为所需的类型“ java.lang.Long”；

Question

org.springframework.beans.TypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Long';

public ModelAndView deleteUploadedSettingsFile(HttpServletRequest request,HttpServletResponse response,@RequestParam("fileId") Long fileId) throws Exception 

    public ModelAndView deleteUploadedSettingsFile(HttpServletRequest request,HttpServletResponse response,@RequestParam("fileId") Long fileId) throws Exception 

Requestlocalhosthttp://localhost:8080/dsd/deleteuploadedsettingsfile%20Threw an Exception
org.springframework.beans.TypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Long'; nested exception is java.lang.NumberFormatException: For input string: "undefined"