java Mybatis 期望 selectOne() 返回一个结果（或 null），但发现：190
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Mybatis Expected one result (or null) to be returned by selectOne(), but found: 190
提问by silentlearner
I am trying to retrieve values from DB, but I can't able to get all the values. I am getting TooManyResultsException.
我正在尝试从数据库中检索值，但无法获取所有值。我得到TooManyResultsException.
MapperInterface
映射器接口
This is the mapper interface which I am invoking.
这是我正在调用的映射器接口。
public interface ITranslatorDAO
{
Map<String, Map<String, String>> translate();
}
mapper.xml
映射器.xml
This part is the SQL which i am running against DB and it has 190 rows.i wanted to retrieve all rows but it is throwing exception as i mentioned below.
这部分是我针对 DB 运行的 SQL，它有 190 行。我想检索所有行，但它抛出异常，如下所述。
<select id="translate" resultType="map">
SELECT
section,
data,
translation
FROM
web_data..wd_ofx_translate
ORDER BY
section,
data,
translation
</select>
Exception traceback
异常回溯
Exception in thread "main" org.mybatis.spring.MyBatisSystemException:
nested exception is org.apache.ibatis.exceptions.TooManyResultsException:
Expected one result (or null) to be returned by selectOne(), but found: 190
回答by Persia
you should add @MapKey to tell mybatis which column in table you want as the key of the map, such as use section column as key of the map :
你应该添加@MapKey来告诉mybatis你想要表中的哪一列作为地图的键，例如使用section列作为地图的键：
public interface ITranslatorDAO{
@MapKey("section")
Map<String, Map<String, String>> translate();
}
回答by JimmyJames
The selectOne() method is used when you want to run a query that selects onerow. If you want to select more than one row, use a different method.
当您想要运行选择一行的查询时，将使用 selectOne() 方法。如果要选择多行，请使用不同的方法。
