如何在Spring MVC中基于http请求头启用json的动态漂亮打印？ [英] How to enable dynamic pretty print of json based on http request header in Spring MVC?

问题描述

我想基于http参数动态地打印来自Spring MVC Restcontrollers的json响应（如此处所示： http://www.vinaysahni.com/best-practices-for-a-pragmatic-restful-api#pretty-print-gzip ）。

I want to pretty print json responses from Spring MVC Restcontrollers dynamically based on a http parameter (like suggested here: http://www.vinaysahni.com/best-practices-for-a-pragmatic-restful-api#pretty-print-gzip).

我发现通过静态配置打印它的配置，但不是如何动态地打印它？

I have found configurations for pretty print it by static configuration, but not how to do that dynamically?

当使用Spring MVC for REST时，如何让Jackson完美地打印呈现的JSON？

知道怎么做吗？

推荐答案

介绍新媒体类型

---

您可以定义新的媒体类型，例如 application / pretty + json 并注册一个新的 HttpMessag转换为该媒体类型的eConverter 。实际上，如果客户端使用 Accept：application / pretty + json 标头发送请求，我们的新 HttpMessageConverter 将写入响应，否则，普通的旧 MappingJackson2HttpMessageConverter 会这样做。

Introducing A New Media Type

---

You can define a new Media Type, say, application/pretty+json and register a new HttpMessageConverter that converts to that Media Type. In fact, if client sends a request with Accept: application/pretty+json header, our new HttpMessageConverter will write the response, Otherwise, the plain old MappingJackson2HttpMessageConverter would do that.

所以，扩展 MappingJackson2HttpMessageConverter 如下所示：

public class PrettyPrintJsonConverter extends MappingJackson2HttpMessageConverter {
    public PrettyPrintJsonConverter() {
        setPrettyPrint(true);
    }

    @Override
    public List<MediaType> getSupportedMediaTypes() {
        return Collections.singletonList(new MediaType("application", "pretty+json"));
    }

    @Override
    public boolean canWrite(Class<?> clazz, MediaType mediaType) {
        boolean canWrite = super.canWrite(clazz, mediaType);
        boolean canWritePrettily = mediaType != null && 
                                   mediaType.getSubtype().equals("pretty+json");

        return canWrite && canWritePrettily;
    }
}

那个 setPrettyPrint（true）构造函数中的将为我们完成。然后我们应该注册这个 HttpMessageConverter ：

That setPrettyPrint(true) in constructor will do the trick for us. Then we should register this HttpMessageConverter:

@EnableWebMvc
@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(new PrettyPrintJsonConverter());
    }
}

正如我所说，如果客户发送请求 application / pretty + json 接受标头，我们的 PrettyPrintJsonConverter 将编写JSON表示 Prettily 。否则， MappingJackson2HttpMessageConverter 会将一个紧凑的JSON写入响应主体。

As i said, if client send a request with application/pretty+json Accept header, our PrettyPrintJsonConverter will write the JSON representation Prettily. Otherwise, MappingJackson2HttpMessageConverter would write a compact JSON to the response body.

您可以使用 ResponseBodyAdvice 甚至拦截器实现相同目标，但在我看来，注册一个全新的 HttpMessageConverter 是更好的方法。

You can achieve the same with a ResponseBodyAdvice or even Interceptors but in my opinion, registering a brand new HttpMessageConverter is the better approach.

这篇关于如何在Spring MVC中基于http请求头启用json的动态漂亮打印？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！