java 如何使用 Spring 配置全局忽略 json 中的“null”或空属性
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How to ignore "null" or empty properties in json, globally, using Spring configuration
提问by Pedro Silva
I'm trying to return only the properties that have values, but the null ones are also being returned.
我试图只返回具有值的属性，但也返回空值。
I know that there's an annotation that does this ( @JsonInclude(Include.NON_NULL)), but then I need these in every single entity class.
我知道有一个注释可以执行此操作 ( @JsonInclude(Include.NON_NULL))，但随后我在每个实体类中都需要这些注释。
So, my question is: Is there a way to configure this globally through spring config? (avoiding XML, preferably)
所以，我的问题是：有没有办法通过 spring 配置全局配置它？（最好避免使用 XML）
EDIT: It seems that this question has been considered a duplicate, but I don't think so. The real question here is how to configure it through spring config, which I couldn't find in other questions.
编辑：似乎这个问题被认为是重复的，但我不这么认为。这里真正的问题是如何通过 spring config 配置它，我在其他问题中找不到。
回答by Jon Peterson
If you are using Spring Boot, this is as easy as:
如果您使用的是 Spring Boot，这很简单：
spring.Hymanson.serialization-inclusion=non_null
If not, then you can configure the ObjectMapper in the MappingHymanson2HttpMessageConverter like so:
如果没有，那么您可以像这样在 MappingHymanson2HttpMessageConverter 中配置 ObjectMapper：
@Configuration
class WebMvcConfiguration extends WebMvcConfigurationSupport {
@Override
protected void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
for(HttpMessageConverter converter: converters) {
if(converter instanceof MappingHymanson2HttpMessageConverter) {
ObjectMapper mapper = ((MappingHymanson2HttpMessageConverter)converter).getObjectMapper()
mapper.setSerializationInclusion(Include.NON_NULL);
}
}
}
}
回答by Abolfazl Hashemi
If you use Hymanson ObjectMapper for generating json, you can define following custom ObjectMapper for this purpose and use it instead:
如果您使用 Hymanson ObjectMapper 生成 json，则可以为此目的定义以下自定义 ObjectMapper 并使用它：
<bean id="HymansonObjectMapper" class="com.fasterxml.Hymanson.databind.ObjectMapper">
<property name="serializationInclusion">
<value type="com.fasterxml.Hymanson.annotation.JsonInclude.Include">NON_NULL</value>
</property>
</bean>
回答by aribeiro
The programmatic alternative to Abolfazl Hashemi's answer is the following:
Abolfazl Hashemi答案的编程替代方案如下：
/**
* Hymanson configuration class.
*/
@Configuration
public class HymansonConfig {
@Bean
public ObjectMapper buildObjectMapper() {
return new ObjectMapper().setSerializationInclusion(Include.NON_NULL);
}
}
This way, you're basically telling to the Spring container that, every time an ObjectMapperis used, only properties with non-null values are to be included in the mappings.
这样，您基本上是在告诉 Spring 容器，每次使用 anObjectMapper时，映射中只包含具有非空值的属性。
