do not allow {} as request body

Question

I have the following post method handler:

@PostMapping("/endpoint")
public int myEndpoint(@RequestBody MyBody body) {
    return body.foo;
}

Which accepts the following request body:

class MyBody {
    private int foo;

    public MyBody() {}

    public MyBody(foo) {
        this.foo = foo;
    }

    public getFoo() {
        return this.foo;
    }
}

Now, I expect that when I make request to /endpoint with body {} It'll return status 400,

but I get 200 and body.foo is 0.

How can I make sure {} body is rejected?

Answer 1

You could validate the body with annotations :

@PostMapping("/endpoint")
public int myEndpoint(@RequestBody @Valid MyBody body) {
    return body.foo;
}

you also need to add validations dependencie

<dependency> 
        <groupId>org.springframework.boot</groupId> 
        <artifactId>spring-boot-starter-validation</artifactId> 
</dependency>

then MyBody is a DTO, don't use primitive types as int since they have a default value. Add the validations you need :

class MyBody {
    @NotNull
    private Integer foo;

    ...
}