上周在与第三方对接接口的时候，由于三方的接口key值均是采用下划线命名的方式，使用传统的JSONObject方式，需要挨个赋值，特别麻烦，而且一点也不面向对象，一点也不极客。

大概实现的效果就是上图这样，三方接口提供的无论是入参还是接参，均是下划线分隔的，接口的需求是驼峰的和下划线分隔的均需要能正常接收，并进行业务逻辑处理，好了，话不多说，上代码！

代码见：jjn0942/jackson-demo-project​gitee.com

首先导入Pom依赖，Jackson的三个Jar包和FastJson(可不要，就是习惯了用而已)：

com.fasterxml.jackson.core

jackson-core

2.12.0-rc1

com.fasterxml.jackson.core

jackson-annotations

2.12.0-rc1

com.fasterxml.jackson.core

jackson-databind

2.12.0-rc1

com.alibaba

fastjson

1.2.74

我们模拟用户注册的场景，提交一系列基本信息，如：

{

"user_name": "jjn",

"org_id": "01",

"org_name": "Class1",

"age": 0,

"email": "jjn@mail.ustc.edu.cn",

"create_time": "2020-11-01 09:11:03"

}

通过接口处理之后生成的数据如下：

{

"code": 200,

"message": "成功",

"info": {

"update_time": "2020-11-01 22:06:45",

"create_time": "2020-11-01 09:11:03",

"registerTime": "2020-11-01 22:06:45",

"user_name": "jjn",

"org_id": "01",

"registered": true,

"org_name": "Class1",

"age": 0,

"email": "jjn@mail.ustc.edu.cn"

}

}

那么是如何实现的呢？其实主要就是Jackson Json库的几个注解，来看看吧~@JsonProperty

/*** Marker annotation that can be used to define a non-static* method as a "setter" or "getter" for a logical property* (depending on its signature),* or non-static object field to be used (serialized, deserialized) as* a logical property.*

* Default value ("") indicates that the field name is used* as the property name without any modifications, but it* can be specified to non-empty value to specify different* name. Property name refers to name used externally, as* the field name in JSON objects.*

* Starting with Jackson 2.6 this annotation may also be* used to change serialization of Enum like so:*

public enum MyEnum {{@literal @JsonProperty}("theFirstValue") THE_FIRST_VALUE,{@literal @JsonProperty}("another_value") ANOTHER_VALUE;}

* as an alternative to using {@link JsonValue} annotation.*/

注释里面写的很清楚了，指定了value的值之后，在生成JSON的时候，会按value的值来。@JsonAlias

/*** Annotation that can be used to define one or more alternative names for* a property, accepted during deserialization as alternative to the official* name. Alias information is also exposed during POJO introspection, but has* no effect during serialization where primary name is always used.*

* Examples:*

*public class Info {*  @JsonAlias({ "n", "Name" })*  public String name;*}*

** @since 2.9*/

alias的意思是别名，value值指定了之后，可以接受多种可能的赋值。

所以最后我们的用户实体类就会写成这样：

package com.zhihu.jjn.demoproject.entity;

import com.fasterxml.jackson.annotation.JsonAlias;

import com.fasterxml.jackson.annotation.JsonFormat;

import com.fasterxml.jackson.annotation.JsonProperty;

import lombok.AllArgsConstructor;

import lombok.Builder;

import lombok.Data;

import lombok.NoArgsConstructor;

import java.util.Date;

/*** @author Jiang Jining* @date 2020/11/1 10:17*/

@Data

@AllArgsConstructor

@NoArgsConstructor

@Builder

public class User {

@JsonProperty(value = "user_name")

@JsonAlias(value = {"user_name", "userName"})

private String userName;

@JsonProperty(value = "org_id")

@JsonAlias(value = {"org_id", "orgId"})

private String orgId;

@JsonProperty(value = "org_name")

@JsonAlias(value = {"org_name", "orgName"})

private String orgName;

private Integer age;

private String email;

@JsonProperty(value = "create_time")

@JsonAlias(value = {"create_time", "createTime"})

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")

private Date createTime;

@JsonProperty(value = "update_time")

@JsonAlias(value = {"update_time", "updateTime"})

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")

private Date updateTime;

private Boolean registered;

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")

private Date registerTime;

}

返回实体类：

package com.zhihu.jjn.demoproject.entity;

import com.alibaba.fastjson.JSONObject;

import lombok.AllArgsConstructor;

import lombok.Builder;

import lombok.Data;

import lombok.NoArgsConstructor;

/*** @author Jiang Jining* @date 2020/11/1 11:08*/

@Data

@AllArgsConstructor

@Builder

@NoArgsConstructor

public class Response {

private Integer code;

private String message;

private JSONObject info;

public static Response success(JSONObject data) {

return Response.builder().code(200).message("成功").info(data).build();

}

public static Response error(JSONObject data) {

return Response.builder().code(500).message("失败").info(data).build();

}

}

service接口：

package com.zhihu.jjn.demoproject.service;

import com.alibaba.fastjson.JSONObject;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.zhihu.jjn.demoproject.entity.User;

/*** @author Jiang Jining* @date 2020/11/1 11:12*/

public interface UserService {

/*** Register user demo.** @param user user param from front end* @return json object*/

JSONObject registerUser(User user) throws JsonProcessingException;

}

service接口实现：

package com.zhihu.jjn.demoproject.service.impl;

import com.alibaba.fastjson.JSON;

import com.alibaba.fastjson.JSONObject;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.zhihu.jjn.demoproject.entity.User;

import com.zhihu.jjn.demoproject.service.UserService;

import org.springframework.stereotype.Service;

import java.util.Date;

/*** @author Jiang Jining* @date 2020/11/1 11:12*/

@Service

public class UserServiceImpl implements UserService {

@Override

public JSONObject registerUser(User user) throws JsonProcessingException {

ObjectMapper objectMapper = new ObjectMapper();

user.setRegistered(true);

user.setRegisterTime(new Date());

user.setUpdateTime(new Date());

String string = objectMapper.writeValueAsString(user);

return JSON.parseObject(string);

}

}

最后的Controller实现：

package com.zhihu.jjn.demoproject.controller;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.zhihu.jjn.demoproject.entity.Response;

import com.zhihu.jjn.demoproject.entity.User;

import com.zhihu.jjn.demoproject.service.UserService;

import org.springframework.web.bind.annotation.CrossOrigin;

import org.springframework.web.bind.annotation.PostMapping;

import org.springframework.web.bind.annotation.RequestBody;

import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

/*** @author Jiang Jining* @date 2020/11/1 11:06*/

@RestController

@CrossOrigin

public class UserController {

@Resource

private UserService userService;

@PostMapping(value = "/api/user/register")

public Response userRegisterController(@RequestBody User user) throws JsonProcessingException {

return Response.success(userService.registerUser(user));

}

}