SpringMVC ResponseBodyAdvice Arayüzü - Response Nesnesi Değiştiren Interceptor

Giriş

Şu satırı dahil ederiz

import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

Spring ile hazır gelen advice'lardan bir tanesi. Açıklaması şöyle

It helps us to modify the message i.e response object before it is written to the Response body.

supports metodu

İmzası şöyle

boolean supports(MethodParameter returnType,
                 Class<? extends HttpMessageConverter<?>> converterType)

Açıklaması şöyle

The MethodParameterargument helps us to check from which class and method the Request is coming and return the boolean value.  Based on it the BeforeBodyRead Method is Called.

beforeBodyWrite metodu

İmzası şöyle

T beforeBodyWrite(@Nullable T body,
                  MethodParameter returnType,
                  MediaType selectedContentType,
                  Class<? extends HttpMessageConverter<>> selectedConverterType,
                  ServerHttpRequest request,
                  ServerHttpResponse response)

Örnek

Şöyle yaparız

@RestControllerAdvice
public class DemoControllerAdvice implements 
  ResponseBodyAdvice<Map<String, String>> {

  @Override
  public boolean supports(
    MethodParameter returnType, 
    Class<? extends HttpMessageConverter<?>> converterType) {

    String className = returnType.getContainingClass().toString();
    String methodName = returnType.getMethod().toString();
    if (className.contains("DemoController_") && 
        methodName.contains("ResponseModification")) {
      return true;
    }
    return false;
  }

  @Override
  public Map<String, String> beforeBodyWrite(
    Map<String, String> body, 
    MethodParameter returnType,
    MediaType selectedContentType, 
    Class<? extends HttpMessageConverter<?>> selectedConverterType,
    ServerHttpRequest request, 
    ServerHttpResponse response) {

    body.put("body_data", "Age of the Person is 25 years");
    return body;
  }
}

Örnek

Şöyle yaparız. Burada @RestControllerAdvice yerine @ControllerAdvice kullanılıyor

@ControllerAdvice
public class ResponseBodyInterceptor implements ResponseBodyAdvice<Object> {

  @Override
  public boolean supports(MethodParameter returnType, 
    Class<? extends HttpMessageConverter<?>> converterType) {
    return true;
  }

  @Override
  public Object beforeBodyWrite(Object body, MethodParameter returnType,
    MediaType selectedContentType, 
    Class<? extends HttpMessageConverter<?>> selectedConverterType,
    ServerHttpRequest request, ServerHttpResponse response) {
    ...
    return body;
  }
}