spring jack 使用自定义的objectMapper。或者在xml配置objectMapper参数

在spring-servlet.xml中配置json的转换器：

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<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">  
        <!-- objectMapper配置 -->  
        <property name="objectMapper">      
             <bean class="com.test.MyObjectMapper" />  
                        <!-- <bean class="com.fasterxml.jackson.databind.ObjectMapper">  
                            驼峰命名法转换为小写加下划线  
                            <property name="propertyNamingStrategy">  
                                <bean class="com.fasterxml.jackson.databind.PropertyNamingStrategy.LowerCaseWithUnderscoresStrategy" />  
                            </property>  
                            为null字段时不输出  
                            <property name="serializationInclusion">  
                                <value type="com.fasterxml.jackson.annotation.JsonInclude.Include">NON_NULL</value>  
                            </property>   
                            禁用空对象转换json校验  
                            <property name="configure">  
                                <value type="com.fasterxml.jackson.databind.SerializationFeature">FAIL_ON_EMPTY_BEANS</value>  
                            </property>  
                            忽略未知的字段  
                            <property name="configure">  
                                <value type="com.fasterxml.jackson.databind.DeserializationFeature">FAIL_ON_UNKNOWN_PROPERTIES</value>  
                            </property>  
                        </bean>  -->  
            </property>  
        <!-- 支持的类型，编码 -->  
        <property name="supportedMediaTypes">  
        <span style="white-space:pre">    </span><list>  
            <span style="white-space:pre">    </span><value>application/json;charset=UTF-8</value>    
            </list>  
    <span style="white-space:pre">    </span></property>  
</bean>   

MyObjectMapper.Java文件如下：

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public class MyObjectMapper extends ObjectMapper {  
  
    private static final long serialVersionUID = 4402127997078513582L;  
  
    public MyObjectMapper() {  
        //设置null值不参与序列化(字段不被显示)    
        this.setSerializationInclusion(Include.NON_NULL);  
          
        // 禁用空对象转换json校验  
        this.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);  
        this.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);  
        //驼峰命名法转换为小写加下划线  
        this.setPropertyNamingStrategy(PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);  
    }  
}