Spring配置檔案中新增：<mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
            <property name="objectMapper">
                <bean class="com.fasterxml.jackson.databind.ObjectMapper"
 
>
                    <property name="serializationInclusion">
                        <value type="com.fasterxml.jackson.annotation.JsonInclude.Include">NON_NULL</value>
                    </property>
                </bean>
            </property>
        </bean
 
>
    </mvc:message-converters>
</mvc:annotation-driven>--------------------------------------------------------------------------------------------------------Spring boot 新增配置類：import java.io.IOException;


import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;


import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;


/** 
 * 〈返回json空值去掉null和""〉 〈功能詳細描述〉 
 *  
 * @version 2017年10月13日 
 */  
@Configuration  
public class JacksonConfig  
{  
    @Bean  
    @Primary  
    @ConditionalOnMissingBean(ObjectMapper.class)  
    public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder)  
    {  
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();  
  
        // 通過該方法對mapper物件進行設定，所有序列化的物件都將按改規則進行系列化  
        // Include.Include.ALWAYS 預設  
        // Include.NON_DEFAULT 屬性為預設值不序列化  
        // Include.NON_EMPTY 屬性為 空（""） 或者為 NULL 都不序列化，則返回的json是沒有這個欄位的。這樣對移動端會更省流量  
        // Include.NON_NULL 屬性為NULL 不序列化  
      //  objectMapper.setSerializationInclusion(Include.NON_NULL);  
  
        // 欄位保留，將null值轉為""  
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>()  
    {  
        @Override  
        public void serialize(Object o, JsonGenerator jsonGenerator,  
                              SerializerProvider serializerProvider)  
                throws IOException, JsonProcessingException  
        {  
            jsonGenerator.writeString("");  
        }  
    });  
        return objectMapper;  
    }  
}