春季靴子泽西杰克逊

问题描述

我有一个与 Spring boot 项目中的 Jackson 配置相关的问题

I have a question related to the Jackson configuration on my Spring boot project

如 spring boot 博客中所述

我尝试自定义对象序列化.

I try to customize my Object serialization.

在我的配置中添加一个新的配置 bean 之后

After added a new config bean in my config

@Bean
public Jackson2ObjectMapperBuilder jacksonBuilder() {
    Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();

    builder.propertyNamingStrategy(PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);
    return builder;
}

当我尝试输出我的类 User 的实例时，json 结果不在 CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES 中

When I try to output an instance of my class User the json result is not in CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES

Class User {
    private String firstName = "Joe Blow";

    public String getFirstName() {
        return firstName;
    }
}

json 输出为:

{
  "firstName": "Joe Blow"
}

而不是

{
  "first_name": "Joe Blow"
}

也许我需要在我的 Jersey 配置中注册一些东西来激活我的自定义 obejctMapper 配置

Maybe I need to register something in my Jersey config to activate my custom obejctMapper Config

@Configuration
public class JerseyConfig extends ResourceConfig {
    public JerseyConfig() {
        packages("my.package);
    }
}

谢谢

推荐答案

为 JAX-RS/Jersey 应用程序配置 ObjectMapper 的一般方法是使用 ContextResolver.例如

The general way to configure the ObjectMapper for JAX-RS/Jersey applications is use a ContextResolver. For example

@Provider
public class ObjectMapperContextResolver implements ContextResolver<ObjectMapper> {

    private final ObjectMapper mapper;

    public ObjectMapperContextResolver() {
        mapper = new ObjectMapper();
        mapper.setPropertyNamingStrategy(
            PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES
        );
    }

    @Override
    public ObjectMapper getContext(Class<?> type) {
        return mapper;
    }
}

它应该通过包扫描被拾取，或者你可以明确注册它，如果它不在包范围内

It should be picked up with the package scan, or you can explicitly register it, if it's not within the package scope

public JerseyConfig() {
    register(new ObjectMapperContextResolver());
    // Or if there's is an injection required
    // register it as a .class instead of instance
}

ContextResolver 在编组和解组期间被调用.被序列化或反序列化的类/类型将传递给 getContext 方法.因此，您甚至可以针对不同类型甚至更多用例使用多个映射器.

The ContextResolver is called during the marshalling and unmarshalling. The class/type being serialzed or deserialized into will be passed to the getContext method. So you could even use more than one mapper for different types, or even more use cases.

从 Spring Boot 1.4 开始，您只需创建一个 ObjectMapper Spring bean，Spring Boot 将为您创建 ContextResolver，并使用您的 ObjectMapper

Starting from Spring Boot 1.4, you can just create an ObjectMapper Spring bean, and Spring Boot will create the ContextResolver for you, and use your ObjectMapper

// in your `@Configuration` file.
@Bean
public ObjectMapper mapper() {}

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