面试官：有一个 List 对象集合，如何优雅地返回给前端？我懵了。。

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public class SceneVO {
 private String sessionId;
 private String sceneId;
 private String sceneName;
 // 省略对应的getter和setter方法
}

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{
 "data":[
  {
   "sessionId": "jksadhjksd",
   "sceneId":"NDJWKSDSJKDKED",
   "sceneName":"场景1"
  },
  {
   "sessionId": "jksadhjksd",
   "sceneId":"KLJSDJKLSDFALK",
   "sceneName":"场景2"
  },
  {
   "sessionId": "jksadhjksd",
   "sceneId":"KERFJKOVDJKDSS",
   "sceneName":"场景3"
  }
 ]
}

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{
 "data": {
  "sessionId": "jksadhjksd",
  "sceneList": [
   {
    "sceneId":"NDJWKSDSJKDKED",
    "sceneName":"场景1"
   },
   {
    "sceneId":"KLJSDJKLSDFALK",
    "sceneName":"场景2"
   },
   {
    "sceneId":"KERFJKOVDJKDSS",
    "sceneName":"场景3"
   }
  ]
 }
}

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public class SceneVO {
 private String sessionId;
 private List<SubSceneVO> sceneList;
 // 省略对应的getter和setter方法
}
public class SubSceneVO {
 private String sceneId;
 private String sceneName;
 // 省略对应的getter和setter方法
}

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public interface BusinessScenesCustomMapper {
 SceneVO selectBySessionId(String sessionId);
}
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="你的包名.mapper.BusinessScenesCustomMapper">
    <resultMap id="BaseResultMap" type="你的包名.vo.SceneVO">
        <result column="session_id" jdbcType="VARCHAR" property="sessionId"/>
    <!--
      collection 标签：用于定义关联的list集合类型的封装规则
      property：对应父类中list属性名，这里SceneVO类里的List变量名为sceneList
      ofType：集合存放的类型，List集合要装的类的类名，这里是SubSceneVO
    -->
        <collection property="sceneList" ofType="你的包名.vo.SubSceneVO">
            <result column="scene_id" jdbcType="VARCHAR" property="sceneId"/>
            <result column="scene_name" jdbcType="VARCHAR" property="sceneName"/>
        </collection>
    </resultMap>

<!-- 一个session_id对应多条记录，返回的是SceneVO对象，SceneVO对象有一个List装着SubSceneVO  -->
    <select id="selectBySessionId" parameterType="string" resultMap="BaseResultMap">
        select session_id, scene_id, scene_name
        from 表名
        where session_id = #{sessionId,jdbcType=VARCHAR}
    </select>
</mapper>

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public interface SceneService {
 /**
 * 获取场景信息
 */
 SceneVO getScenesInfo(String sessionId);
}
@Service
public class SceneServiceImpl {

 @Resource
 private BusinessScenesCustomMapper businessScenesCustomMapper;
 ......
 public SceneVO getScenesInfo(String sessionId) {
  return businessScenesCustomMapper.selectBySessionId(sessionId);
 }
}

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......
@Resource
private SceneService sceneService;

@GetMapping("/getScenesInfo")
public ResModel getScenesInfo(String sessionId) {
 SceneVO sceneVO = sceneService.getScenesInfo(sessionId);
 return ResModel.ok(sceneVO);
}