解决方案:
1)写sql语句时起别名,例如:
更改last_name为lastName
更改dept_id为deptId
select id,last_name lastName,email,salary,dept_id deptId
from ...
where ...
2)在MyBatis的全局配置文件中开启驼峰命名规则
<configuration>
<settings>
<setting name="mapUnderscoreToCamelCase" value="true">
</settings>
.......
</configuration>
3)在Mapper映射文件中使用resultMap来自定义映射规则
<select id="getEmployeeById" resultMap="myMap">
</select>
<resultMap type="com.diko.Employee" id="myMap">
<id column="id" property="id">
<result column="last_name" property="lastName">
......
</resultMap>