先说一个自己总能碰见的问题，今天终于解决
在Test(测试类)中，引@Test有时会报错，大多数是因为复制过来的代码所以造成这种原因，这个时候你肯定想到的是pom.xml，里面jar包没有引入，可是如果引入了还报错是为什么呢，这是因为，你的XXX.iml里面没有加上这些
下面是智能标签：
<!--智能标签foreach List自定义-->
<select id="findByListGeneric" resultType="Student">
select
<include refid="columns"></include> from student
<if test="list.size>0">
WHERE stuno in
<foreach collection="list" open="(" close=")" separator="," item="myitem">
#{myitem.stuno}
</foreach>
</if>
</select>
<!--智能标签foreach List-->
<select id="findByList" resultType="Student">
select
* from student
<if test="list.size>0">
WHERE stuno in
<foreach collection="list" open="(" close=")" separator="," item="myid">
#{myid}
</foreach>
</if>
</select>
<!--智能标签foreach-->
<select id="findByArray" resultType="Student">
select
* from student
<if test="array.length>0">
WHERE stuno in
<foreach collection="array" open="(" close=")" separator="," item="myid">
#{myid}
</foreach>
</if>
</select>
<!--智能标签choose-->
<select id="findByChoose" resultType="Student">
select
* from student
<where>
<choose>
<when test="stuname != null">
and stuname like '%' #{stuname} '%'
</when>
<when test="stuage!=null">
and stuage>#{stuage}
</when>
<otherwise>
and 1=1
</otherwise>
</choose>
</where>
</select>
<!--智能标签if-->
<select id="findByIf" resultType="Student">
select
* from student
<where>
<if test="stuname!=null">
and stuname like '%' #{stuname} '%'
</if>
<if test="stuage!=null">
and stuage>#{stuage}
</if>
</where>
</select>
下面是一对多：
<resultMap id="DeptMapperMultipleSQL" type="Dept">
<id column="deptNo" property="deptNo"></id>
<result column="deptName" property="deptName"></result>
<collection property="emps" ofType="Emp" select="selectEmpsById" column="deptno">
</collection>
</resultMap>
<select id="selectEmpsById" resultType="Emp">
select
* from emp where deptno=#{deptNo}
</select>
<!--一对多的单条SQL解决方案-->
<select id="findEmpsByDeptNoMultipleSQL" resultMap="DeptMapperMultipleSQL">
select deptName,deptNo
from dept
where deptno=#{deptNo}
</select>
<resultMap id="DeptMapper" type="Dept">
<id column="deptNo" property="deptNo"></id>
<result column="deptName" property="deptName"></result>
<!--
ofType:集合中单个元素的类型
-->
<collection property="emps" ofType="Emp">
<id column="empNo" property="empNo"></id>
<result column="empName" property="empName"></result>
</collection>
</resultMap>
<select id="findEmpsByDeptNo" resultMap="DeptMapper">
select empNo,empName,deptName,dept.deptNo
from emp,dept
where emp.deptno=dept.deptno
and dept.deptno=#{deptNo}
</select>
