Spring MVC,在普通请求中强制JSON响应

@RequestMapping(value = "/example", method = RequestMethod.GET)
@ResponseBody
public Map<String, Object> example() {
    Map<String, Object> response = new HashMap<>();
    response.put("key", "value");
    return response;
}

@RestController
public class ExampleController {
    @RequestMapping(value = "/example", method = RequestMethod.GET)
    public Map<String, Object> example() {
        Map<String, Object> response = new HashMap<>();
        response.put("key", "value");
        return response;
    }
}

public class ExampleView {
    public interface DefaultView {
    }
}

@RestController
public class ExampleController {
    @RequestMapping(value = "/example", method = RequestMethod.GET)
    public Map<String, Object> example() {
        Map<String, Object> response = new HashMap<>();
        response.put("key", "value");
        return response;
    }
}

@RequestMapping(value = "/example", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
public Map<String, Object> example() {
    Map<String, Object> response = new HashMap<>();
    response.put("key", "value");
    return response;
}