<!-- 根据主键id查询订单信息-->
<select id="getExployeeByUserId" parametertype="java.lang.string" resulttype="com.my.vo.Exployee">
select
a.user_id as userId,
a.user_code as userCode,
a.user_name as userName,
a.status status,
a.finish_time as finishTime,
a.create_time as createTime
from
t_exployee a
where a.user_id = #{userId,jdbctype=varchar}
</select>
<select id="getExployeeByUserCode" parametertype="java.lang.string" resulttype="com.my.vo.Exployee">
select
a.user_id as userId,
a.user_code as userCode,
a.user_name as userName,
a.status status,
a.finish_time as finishTime,
a.create_time as createTime
from
t_exployee a
where a.user_code = #{userCode,jdbctype=varchar}
</select>
public class Exployee {
private static final long serialVersionUID = 1L;
private String userId;
private String userCode;
private String userName;
private String status;
private Date createTime;
private Date finishTime;
//自动生成set、get方法
｝
两个查询，参数和返回都是一样的，getExployeeByUserId 百试不爽，必定查询出结果；但是getExployeeByUserCode查询，时不时的查询结果返回为null，明明是有数据的；愁死我了，你要是一直查不出来也行啊，一会有，一会没有。百度的时候，有说是因为数据库表的字段和java的实体类字段对不上，建议配置ResultMap；查询返回的时候，用resultMap="setExployee" 而不是resultType
<resultMap id="setExployee" type="com.my.vo.Exployee">
<result column="user_id" property="userId" jdbcType="VARCHAR"/>
<result column="user_code" property="userCode" jdbcType="VARCHAR"/>
<result column="user_name" property="userName" jdbcType="VARCHAR"/>
<result column="status" property="status" jdbcType="VARCHAR"/>
<result column="create_time" property="createTime" jdbcType="TIMESTAMP"/>
<result column="finish_time" property="finishTime" jdbcType="TIMESTAMP"/>
</resultMap>
数据库表的字段和java的实体类字段对不上，这是原因之一，可以先核实一下，排除一下是不是这个原因；我反正不是这个原因
我的情况是这样的user_id 是主键，这个查询百分百；但是user_code不是主键，在mybatis里面，非主键查询可能不会返回唯一值，所以返回结果不能用单实体，必须要用List类型接收，我后来把接口方法改成返回List，就能查询出结果了。
也是绕了好久，各种排查