如何在Spring MVC(非Spring Boot)应用程序中自定义Jackson [英] How to customize Jackson in Spring MVC (not Spring Boot) application

问题描述

Spring MVC 4.3.29和Java 8(当前平台限制)，以及大多数XML配置，除了一些注释注释的Controller类.

Spring MVC 4.3.29 and Java 8 (current platform constraints), and mostly XML configuration, except for some Controller classes that are annotation-scanned.

简而言之，我想让Spring JSON反序列化自动使用ObjectMapper实例，并将其FAIL_ON_UNKNOWN_PROPERTIES设置回true.

In short, I want to get the ObjectMapper instance being used automatically by Spring JSON deserialization, and I want to set its FAIL_ON_UNKNOWN_PROPERTIES back to true.

我看到了相关 <一个href ="https://stackoverflow.com/questions/30060006/how-do-i-obtain-the-jackson-objectmapper-in-use-by-spring-4-1">问题，但是所有示例似乎都是 Spring Boot 和/或Java配置.在我的WebSphere环境中，所有建议的@Autowired Bean(映射器，Builder等)都没有任何值.

I see several related questions, but all the examples seem to be Spring Boot and/or Java configuration. And none of the suggested @Autowired beans (Mapper, Builder, etc.) have any values at all in my WebSphere environment.

希望我只是在某个地方缺少一些简单的胶水.

Hopefully I'm just missing some simple glue somewhere.

B，我以为我已经拥有了它:

Bah, I thought I had it with this:

@Configuration
public class CustomWebConfiguration extends WebMvcConfigurerAdapter {

    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {

        for (HttpMessageConverter<?> converter : converters) {
            if (converter instanceof MappingJackson2HttpMessageConverter) {
                ((MappingJackson2HttpMessageConverter) converter).getObjectMapper().
                    enable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
                break;
            }
        }
    }
}

通过调试器，我可以看到它被命中并更改了预期的标志.但是，当使用时，该行为无效.我不再有任何XML替代，但是我仍然有"master"标记. <mvc:annotation-driven/>在那里.我想知道它们是否使彼此混淆...

And with my debugger I can see that it is being hit and changing the expected flag. But when used, the behavior is not in effect. I no longer have any XML overrides in place, but I do still have the "master" <mvc:annotation-driven/> there. I wonder if those are confusing each other...

推荐答案

好，是的，只要与@EnableWebMvc而不是<mvc:annotation-driven/>结合使用，它就可以工作:

Ok, yes, this works as long as it's combined with @EnableWebMvc rather than <mvc:annotation-driven/>:

@EnableWebMvc
@Configuration
public class CustomWebConfiguration extends WebMvcConfigurerAdapter {

    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {

        for (HttpMessageConverter<?> converter : converters) {
            if (converter instanceof MappingJackson2HttpMessageConverter) {
                ((MappingJackson2HttpMessageConverter) converter).getObjectMapper().
                    enable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
                break;
            }
        }
    }
}

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