Spring MVC 中如需設置Jackson的一些參數，可以這么干

<mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
            <property name="objectMapper">
                <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                    <property name="featuresToEnable">
                        <array>
                            <util:constant static-field="com.fasterxml.jackson.databind.SerializationFeature.WRAP_ROOT_VALUE" />
                        </array>
                    </property>
                </bean>
            </property>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

解釋，上面那這個例子是我實際的配置節選，配置輸出json時把對象作為根元素。通過配置jackson的SerializationFeature.WRAP_ROOT_VALUE來達到目的。

SerializationFeature.WRAP_ROOT_VALUE：是否環繞根元素，默認false，如果為true，則默認以類名作為根元素，你也可以通過@JsonRootName來自定義根元素名稱。

objectMapper.configure(SerializationFeature.WRAP_ROOT_VALUE,true); 

實例：

@JsonRootName("myPojo")  
public static class TestPOJO{  
    private String name;  
  
    public String getName() {  
        return name;  
    }  
  
    public void setName(String name) {  
        this.name = name;  
    }  
}

該類在序列化成json后類似如下：{"myPojo":{"name":"aaaa"}}

Spring MVC默認配置就只需一個 <mvc:annotation-driven\>，文檔( http://docs.spring.io/spring/docs/4.0.x/spring-framework-reference/html/mvc.html#mvc-config-enable )里說了會加載一大串converter，而Jackson有很多配置項，要達到能夠自由配置Jackson的目的，按照參考http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/http/converter/json/Jackson2ObjectMapperFactoryBean.html里的內容，我們還可以做如下配置。

<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
   <property name="objectMapper">
     <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean"
       p:autoDetectFields="false"
       p:autoDetectGettersSetters="false"
       p:annotationIntrospector-ref="jaxbAnnotationIntrospector" />
   </property>
</bean>

或者

<bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
   <property name="objectMapper">
     <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean"
       p:failOnEmptyBeans="false"
       p:indentOutput="true">
       <property name="serializers">
         <array>
           <bean class="org.mycompany.MyCustomSerializer" />
         </array>
       </property>
     </bean>
   </property>
</bean>

如果沒有可直接用的setter屬性

<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
   <property name="featuresToEnable">
     <array>
       <util:constant static-field="com.fasterxml.jackson.databind.SerializationFeature$WRAP_ROOT_VALUE"/>
       <util:constant static-field="com.fasterxml.jackson.databind.SerializationFeature$CLOSE_CLOSEABLE"/>
     </array>
   </property>
   <property name="featuresToDisable">
     <array>
       <util:constant static-field="com.fasterxml.jackson.databind.MapperFeature$USE_ANNOTATIONS"/>
     </array>
   </property>
</bean>

進而用自定義Module來配置 ObjectMapper

<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
   <property name="modulesToInstall" value="myapp.jackson.MySampleModule,myapp.jackson.MyOtherModule"/>
</bean>

 

更多Jackson的配置請參考：http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/http/converter/json/Jackson2ObjectMapperFactoryBean.html