# 实体类的json/对象转换工具类 以下以QuestionVo为例，对其中的tags和judgeConfig字段进行json和对象的转换. \> 场景：在与前端交互中，tags和judgeConfig需要存储多个数据或字段，所以在QuestionVo中分别为List和JudgeConfig类型。而在数据库的存储中，tags标签有多个数据，为避免库中数据的冗余，先将其转成json字符串在存入数据库；JudgeConfig类中的字段在开发过程中不确定因素较多，为方便对字段进行扩展和修改，将其转成json字符串再存入数据库。 ### QuestionVo实体类 \`\`\`java /\*\* \* 题目封装类 \* @TableName question \*/ @Data public class QuestionVO implements Serializable { private Long id; private String title; private String content; private List tags; private Integer submitNum; private Integer acceptedNum; private JudgeConfig judgeConfig; private Integer thumbNum; private Integer favourNum; private Long userId; private Date createTime; private Date updateTime; private UserVO userVO; /\*\* \* 包装类转对象 \* \* @param questionVO \* @return \*/ public static Question voToObj(QuestionVO questionVO) { if (questionVO == null) { return null; } Question question = new Question(); BeanUtils.copyProperties(questionVO, question); List tagList = questionVO.getTags(); if (tagList != null) { question.setTags(JSONUtil.toJsonStr(tagList)); } JudgeConfig voJudgeConfig = questionVO.getJudgeConfig(); if (voJudgeConfig != null) { question.setJudgeConfig(JSONUtil.toJsonStr(voJudgeConfig)); } return question; } /\*\* \* 对象转包装类 \* \* @param question \* @return \*/ public static QuestionVO objToVo(Question question) { if (question == null) { return null; } QuestionVO questionVO = new QuestionVO(); BeanUtils.copyProperties(question, questionVO); List tagList = JSONUtil.toList(question.getTags(), String.class); questionVO.setTags(tagList); String judgeConfigStr = question.getJudgeConfig(); questionVO.setJudgeConfig(JSONUtil.toBean(judgeConfigStr, JudgeConfig.class)); return questionVO; } private static final long serialVersionUID = 1L; } \`\`\` ### Question实体类 \`\`\`java /\*\* \* 题目 \* @TableName question \*/ @TableName(value ="question") @Data public class Question implements Serializable { @TableId(type = IdType.ASSIGN_ID) private Long id; private String title; private String content; private String tags; private String answer; private Integer submitNum; private Integer acceptedNum; private String judgeCase; private String judgeConfig; private Integer thumbNum; private Integer favourNum; private Long userId; private Date createTime; private Date updateTime; @TableLogic private Integer isDelete; @TableField(exist = false) private static final long serialVersionUID = 1L; } \`\`\` ### JudgeConfig实体类 \`\`\`java /\*\* \* 题目配置 \*/ @Data public class JudgeConfig { private Long timeLimit; private Long memoryLimit; private Long stackLimit; } \`\`\`