以userdao.xml为列:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="ssmDemo.UserDao">
<resultMap id="user" type="User">
<id property="id" column="id"/>
<result property="name" column="name"/>
<result property="age" column="age"/>
<result property="sex" column="sex"/>
<result property="email" column="email"/>
</resultMap>
<!--根据id查询User的数据-->
<select id="getUser" resultType="user" parameterType="int">
SELECT * FROM USER WHERE id=#{id}
</select>
<!--根据name查询User的数据集合-->
<select id="getUserList" resultType="user" parameterType="string">
SELECT * from USER where name=#{name}
</select>
<!--根据age查询User-->
<select id="getUserAge" resultType="user" parameterType="int">
SELECT * from USER WHERE age=#{age}
</select>
<!--根据性别,姓名,email查询User集合,用动态sql来判断-->
<select id="getAge" resultType="user" parameterType="int">
SELECT * from USER
WHERE
<if test="sex!=null">
sex=#{sex}
</if>
<if test="name!=null and name!=''">
and name like #{name}
</if>
<if test="email!=null and email.trim()!=''">
and email=#{email}
</if>
</select>
</mapper>