@RequestBody where object can be 2 different class-CodePudding

I have a controller with @RequestBody

@PostMapping("/")
    public String doSomething(@RequestBody ??? foo)

foo can be 2 different objects. Foobject or Barobject. I don't know what will the object sent. These objects are totally different without any kind of common fields where I could use @JsonTypeInfo and @JsonSubTypes

I can workaround this and use ObjectMapper to try to map it to on of the 2 classes:

@RequestBody Object json
...
ObjectMapper objectMapper = new ObjectMapper();
try {
Foobject obj = objectMapper.convertValue(json, Foobject.class);
}
catch (IllegalArgumentException ei){
        Barobject obj = objectMapper.convertValue(json, Barobject.class);
}

Is there a proper way to do this? Or better said, alternatives? I know this goes against REST API development, because this should be another method, each with its own object.

CodePudding user response：

You can choose to use, Object, class like this and then take advantage of the function

mapper.readValue(jsonStr, Fooobject.class);

method throws JsonMappingException

@PostMapping("/")
public String doSomething(@RequestBody Object foo) {...}

boolean isA(String json, Class expected) {
  try {
     ObjectMapper mapper = new ObjectMapper();
     mapper.readValue(json, expected);
     return true;
  } catch (JsonMappingException e) {
     e.printStackTrace();
     return false;
  } 
}

Well you said that "I don't know what will the object sent", so you can only do trial and error.

Else modify your request to involve a "Type" or something (I would do this by Making a parent class with only "type" member of ObjectType type, and child classes extending that parent class.

enum ObjectType {FOO, BAR}

Method 1: Use readValue() function of jackson
Method 2: Do a string search (just to make it faster) something unique non-nullable field about any of the object.
Method 3: Modify the request.

CodePudding user response：

Managed to do it with Jackson. Create parent class, and both objects extend from parent. On the parent added:

@JsonTypeInfo(use = JsonTypeInfo.Id.DEDUCTION)
@JsonSubTypes({
        @JsonSubTypes.Type(Foobject.class),
        @JsonSubTypes.Type(Barobject.class),,
})

This works pretty well, and I guess is a clean solution. Also, has the advantage to be done on a Spring layer, where other validations defined on fields of the classes will occur.

That wasn't the case with other solutions.