SpringBoot（五）ResponseBodyAdvice

因为SpringBoot默认的ResponseBody的处理程序就是HandlerMethodReturnValueHandler，所以我们自己写的HandlerMethodReturnValueHandler通常无法生效，

非要使用HandlerMethodReturnValueHandler，那么只能替换掉默认的，

如果只是想对Controller的所有返回值进行封装，使用ResponseBodyAdvice会更加简单一些，下面几行代码就足够了

import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

import java.util.HashMap;
import java.util.Map;

/**
 * Created by 12614 on 2018/5/11.
 */
@ControllerAdvice
public class TestResponseAdvice implements ResponseBodyAdvice<Object>{
    @Override
    public boolean supports(MethodParameter methodParameter,
                            Class<? extends HttpMessageConverter<?>> aClass) {
        return methodParameter.hasMethodAnnotation(ResponseBody.class);
    }

    @Override
    public Object beforeBodyWrite(Object o, MethodParameter methodParameter,
                                  MediaType mediaType,
                                  Class<? extends HttpMessageConverter<?>> aClass,
                                  ServerHttpRequest serverHttpRequest,
                                  ServerHttpResponse serverHttpResponse) {
        Map<String,Object> res = new HashMap<>();
        res.put("code","1");
        res.put("data",o);
        return res;
    }
}