I am not sure why this is happening. My return statement for spring boot rest controller is something like below
return ResponseEntity.status(HttpStatus.OK).body("Successfully added");
Now on swagger UI i see response as below
can't parse JSON. Raw result:
Successfully added
why is this happening ?
This is happening because you are returning a string literal instead of a JSON object. I presume your return type would have been ResponseEntity<String> but this would not work and you would need to specify an object in the body. You can create a POJO that will hold the message for you, something like this:
public class YourResponseClass {
private String message;
//Constructors, getter and setter
}
Then while returning you need to change the return type to ResponseEntity<YourResponseClass> and then return your response:
return ResponseEntity.ok(new YourResponseClass("Successfully Added."));
Late to the game but will share my solution to this issue, as it surfaced for me in a Python Flask-based REST backend I was developing recently. You could have NaN values in your JSON, if your issue was similar to mine, albeit in Python.
I too was getting "can't parse JSON" on the swagger side. Turns out that Python's standard library json import will allow "modern" but not-officially-JSON types, such as "NaN". And doing some calculations with floats and voila...As a strict parser fails with a type such as NaN, it's worth checking that you don't have these in your request JSON response.
Though not a Java-specific answer, maybe my Python solution can help you solve the issue.
json.dumps(yourdata, cls=NumpyEncoder)
Where NumpyEncoder is some class that converts NaN values to JSON and/or your acceptable specifications. It might be the case that you too can include some encoder class in your code to remove NaN and/or other artifacts.
See my so answer for Python implementation details.
It is hard to say without seeing more code and the actual Swagger JSON, but it seems like the JSON has a syntax issue. Run it through a JSON validator to confirm. There are plenty of websites for this if you Google it.
