如何自定义Spring Boot隐式使用的Jackson JSON映射器？ [英] How to customise the Jackson JSON mapper implicitly used by Spring Boot?

问题描述

我正在使用Spring Boot（1.2.1），其方式与相似构建RESTful Web服务教程：

I'm using Spring Boot (1.2.1), in a similar fashion as in their Building a RESTful Web Service tutorial:

@RestController
public class EventController {

    @RequestMapping("/events/all")
    EventList events() {
        return proxyService.getAllEvents();
    }

}

因此，Spring MVC暗中使用Jackson将我的 EventList 对象序列化为JSON。

So above, Spring MVC implicitly uses Jackson for serialising my EventList object into JSON.

但我想对JSON格式进行一些简单的自定义，例如：

But I want to do some simple customisations to the JSON format, such as:

setSerializationInclusion(JsonInclude.Include.NON_NULL)

问题是，自定义隐式JSON映射器的最简单方法是什么？

我在 此博文中尝试了该方法/ strong>，创建一个CustomObjectMapper等，但步骤3在Spring上下文中注册类失败：

I tried the approach in this blog post, creating a CustomObjectMapper and so on, but the step 3, "Register classes in the Spring context", fails:

org.springframework.beans.factory.BeanCreationException: 
  Error creating bean with name 'jacksonFix': Injection of autowired dependencies failed; 
  nested exception is org.springframework.beans.factory.BeanCreationException: 
  Could not autowire method: public void com.acme.project.JacksonFix.setAnnotationMethodHandlerAdapter(org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter); 
  nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: 
  No qualifying bean of type [org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter]   
  found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}

看起来这些指令适用于旧版本的Spring MVC，而我我正在寻找一种简单的方法来使用最新的Spring Boot。

It looks like those instructions are for older versions of Spring MVC, while I'm looking for a simple way to get this working with latest Spring Boot.

推荐答案

如果您使用的是Spring Boot 1.3，那么可以通过 application.properties 配置序列化包含：

If you're using Spring Boot 1.3, you can configure serialisation inclusion via application.properties:

spring.jackson.serialization-inclusion=non_null

在Jackson 2.7中进行更改后，Spring Boot 1.4使用名为<$ c的属性$ c> spring.jackson.default-property-inclusion 而不是：

Following changes in Jackson 2.7, Spring Boot 1.4 uses a property named spring.jackson.default-property-inclusion instead:

spring.jackson.default-property-inclusion=non_null

参见自定义Jackson ObjectMapper 部分在Spring启动文档。

See "Customize the Jackson ObjectMapper" section in Spring Boot documentation.

如果你使用早期版本的Spring Boot，在Spring Boot中配置序列化包含的最简单方法是声明自己的，适当配置的 Jackson2ObjectMapperBuilder bean。例如：

If you're using an earlier version of Spring Boot, the easiest way to configure serialisation inclusion in Spring Boot is to declare your own, appropriately configured Jackson2ObjectMapperBuilder bean. For example:

@Bean
public Jackson2ObjectMapperBuilder objectMapperBuilder() {
    Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
    builder.serializationInclusion(JsonInclude.Include.NON_NULL);
    return builder;
}

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