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

<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>

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);
    }
}