import java.io.Serializable;

 import lombok.AllArgsConstructor;

 import lombok.Data;

 import lombok.NoArgsConstructor;

 @Data

 @AllArgsConstructor

 @NoArgsConstructor

 public class User implements Serializable {

     /**

      *

      */

     private static final long serialVersionUID = -329066647199569031L;

     private String userName;

     private String orderNo;

 }

 import java.io.IOException;

 import com.fasterxml.jackson.annotation.JsonInclude.Include;

 import com.fasterxml.jackson.core.JsonProcessingException;

 import com.fasterxml.jackson.databind.ObjectMapper;

 import com.fasterxml.jackson.databind.PropertyNamingStrategy;

 /**

  * JSON的驼峰和下划线互转帮助类

  *

  * @author yangzhilong

  *

  */

 public class JsonUtils {

     /**

      * 将对象的大写转换为下划线加小写，例如：userName-->user_name

      *

      * @param object

      * @return

      * @throws JsonProcessingException

      */

     public static String toUnderlineJSONString(Object object) throws JsonProcessingException{

         ObjectMapper mapper = new ObjectMapper();

         mapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);

         mapper.setSerializationInclusion(Include.NON_NULL);

         String reqJson = mapper.writeValueAsString(object);

         return reqJson;

     }

     /**

      * 将下划线转换为驼峰的形式，例如：user_name-->userName

      *

      * @param json

      * @param clazz

      * @return

      * @throws IOException

      */

     public static <T> T toSnakeObject(String json, Class<T> clazz) throws IOException{

         ObjectMapper mapper = new ObjectMapper();
　　        // mapper的configure方法可以设置多种配置（例如：多字段 少字段的处理）
　　　　　　 //mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

         mapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);

         T reqJson =  mapper.readValue(json, clazz);

         return reqJson;

     }

 }

 import java.io.IOException;

 import org.junit.Test;

 import com.alibaba.fastjson.JSONObject;

 import com.fasterxml.jackson.core.JsonProcessingException;

 public class JsonTest {

     @Test

     public void testToUnderlineJSONString(){

         User user = new User("张三", "1111111");

         try {

             String json = JsonUtils.toUnderlineJSONString(user);

             System.out.println(json);

         } catch (JsonProcessingException e) {

             e.printStackTrace();

         }

     }

     @Test

     public void testToSnakeObject(){

         String json = "{\"user_name\":\"张三\",\"order_no\":\"1111111\"}";

         try {

             User user = JsonUtils.toSnakeObject(json, User.class);

             System.out.println(JSONObject.toJSONString(user));

         } catch (IOException e) {

             e.printStackTrace();

         }

     }

 }

 {"user_name":"张三","order_no":"1111111"}

 {"orderNo":"1111111","userName":"张三"}