mybatis.selectOne

Mybatis.selectOne是什么？

Mybatis.selectOne是Mybatis框架中的一个方法，用于执行单条SQL查询语句并返回查询结果。该方法接收一个查询语句的ID和一个参数对象作为参数，返回一个与该查询语句返回结果相应类型的Java对象。在Mybatis中，使用该方法可以避免手动执行JDBC代码，并使得数据访问层的代码更加简洁和易于维护。

相关问题

@Data List<String> userGroupIds; There is no getter for property named 'deviceTypeIds' in 'class com.zte.smarthome.shcp.upgradeweb.interfaces.dto.CpeQuickSearchConditions' at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:96) at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:441) at com.sun.proxy.$Proxy221.selectOne(Unknown Source) at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:160) List<String> @Data 不能 get吗

@Data 注解会自动为类生成 getter 和 setter 方法，所以 List<String> userGroupIds 会有对应的 getter 方法，但是异常信息中提到了一个属性名为 'deviceTypeIds' 的属性没有 getter 方法，可能是因为该属性没有被 @Data 注解包含进去。请检查代码中是否缺少了相应的注解或 getter 方法。

{ "timestamp": "2023-06-01T08:48:12.746+0000", "status": 500, "error": "Internal Server Error", "message": "nested exception is org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 20", "trace": "org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 20\r\n\tat org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:92)\r\n\tat org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:440)\r\n\tat com.sun.proxy.$Proxy95.selectOne(Unknown Source)\r\n\tat org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:159)\r\n\tat com.baomidou.mybatisplus.core.override.MybatisMapperMethod.execute(MybatisMapperMethod.java:89)\r\n\tat

Based on the error message, it seems that there was an issue with a MyBatis query. The query was expecting only one result (or null) to be returned, but it found 20 results instead. This could be caused by a variety of factors, such as incorrect query logic or data duplication in the database. To further diagnose the issue, it would be helpful to review the MyBatis configuration and the specific query being executed.