Spring @RequestParam with defaultValue of empty string on String parameter gives null but not empty String

I'm using a @RequestParam on a String parameter, gives defaultValue = "". When I call the api without this parameter, I suppose to get an empty value of String "" but got null in my case.

Example that creates the bug:

@GetMapping
public String search(@RequestParam(defaultValue = "") String email) {
    System.out.println("Email should be an empty string if not provided: " + email);
    return email;
}

When I call this api with no parameter, I got "null" in my console rather than "" (empty String value).

Comment From: sbrannen

What do you mean by “call this API”?

How are you invoking the API?

MockMvc, WebTestClient, …?

Comment From: Adamatoma

What do you mean by “call this API”?

How are you invoking the API?

MockMvc, WebTestClient, …?

Hi sbrannen, Thanks for replying! I put this part of code into a controller file in a java web spring-boot project as an restful API. Then use postman to send requeset to invoke this API.

Hope the following code example helpful

@RestController
@RequestMapping(value = "/testurl/url", produces = "application/json")
public class emailController {
    @GetMapping
    public String search(@RequestParam(defaultValue = "") String email) {
        System.out.println("Email should be an empty string if not provided: " + email);
        return email;
    }
}

Then call this api with postman with GET Http request with url like127.0.0.1:8080/testurl/url

Comment From: rstoyanchev

I was not able to reproduce the issue. Please provide a sample that reproduces the issue.

Comment From: spring-projects-issues

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Comment From: spring-projects-issues

Closing due to lack of requested feedback. If you would like us to look at this issue, please provide the requested information and we will re-open the issue.