如何使用 Spring 引导传入请求将多部分文件映射到 DTO

Question

I have this DTO Request Class

Public Class MyRequestDTO(){

private String name;

private MultipartFile docPic;

}

i want to retrieve in in controller

@PostMapping("/test")
public String test(@RequestBody MyRequestDTO dto){

system.out.print(dto.getdocPic.getOriginalFileName());

return "success;
}

but always get javaNullexception when i try to display this newly requested file, is it correct to mapping multipart file inside DTO?

Answer 1

With the latest spring boot we have a running example without the @RequestBody annotation, so try this:

@PostMapping("/test")
public String test(MyRequestDTO dto){

If that doesn't work, the next spot you should double check is your request. Specifically the Content-type . The above signature works for us with a request that has a content type of: multipart/form-data

Answer 2

You're getting javaNullexception because you're receiving MyRequestDTO dto as null or some property of dto object is pointing to null.

So please be sure before calling the getter method on a null object.

Firstly get that dto.getdocPic is not pointing to null.

@PostMapping("/test")
public String test(@RequestBody MyRequestDTO dto){

    if(dto.getdocPic() != null){
        
         system.out.print(dto.getdocPic().getOriginalFileName());
    }

    return "success;

}