Select元素标签输入方式
基本数据类型
字符串类型
Map 类型
Java bean 类型
案例实操
输入参数分类
基本类型，字符串，java bean,map，数组（删除操作时体现），List（添加时体现）等每种情况定义如下
基本数据类型
Statement 定义
<select id="queryCustomerById" parameterType="int" resultType="com.xxx.pojo.Customer">
SELECT id,user_name 'userName',user_balance 'userBalance' FROM yg_customer WHERE id=#{id}
</select>
CustomerDao方法定义
Customer queryCustomerById(int id);
字符串类型
Statement 定义
<select id="queryCustomerByName" parameterType="string" resultType="com.xxx.pojo.Customer">
SELECT id,user_name 'userName',user_balance 'userBalance' FROM yg_customer WHERE user_name=#{userName}
</select>
Dao 方法定义
Customer queryCustomerById(int id);
Map 类型
Statement 定义
<select id="queryCustomerByName" parameterType="map" resultType="com.xxx.pojo.Customer">
SELECT id,user_name 'userName',user_balance 'userBalance' FROM yg_customer WHERE user_name=#{userName}
</select>
Dao 方法定义
Customer queryCustomerByName(Map<String,Object> userName);
Java bean 类型
Statement 定义
<select id="queryCustomerByParams" parameterType="customer" resultType="customer">
SELECT id,user_name 'userName',user_balance 'userBalance' FROM yg_customer WHERE user_name=#{userName}
</select>
Dao方法定义
Customer queryCustomerByParams(Customer customer);
####
扩展
结果类型分类
基本数据类型，字符串，JavaBean，Map,List等
基本数据类型
Statement定义
<select id="queryCustomerAccount" resultType="int">
select count(1) from yg_customer
</select>
Dao 方法定义与对应实现
int queryCustomerAccount();
字符串类型
Statement定义
<select id="queryCustomerNameById" resultType="string" parameterType="int">
select user_name from yg_customer WHERE id=#{id}
</select>
Dao 方法定义
String queryCustomerNameById(int id);
Java Bean
Statement定义
<select id="queryUserByUser" parameterType="user" resultType="user">
select id,user_name as userName,user_pwd as userPwd from user where id=#{id}
</select>
List
Statement 定义
<resultMap type="user" id="user_map">
<result column="id" property="id"/>
<result column="user_name" property="userName"/>
<result column="user_pwd" property="userPwd"/>
</resultMap>
<sql id="user_column">
id,user_name,user_pwd
</sql>
<select id="queryUserNyName2" parameterType="string" resultMap="user_map">
select <include refid="user_column"/>
from user where user_name like concat("%",#{userName},"%")
</select>
Map 类型数据
Statement 定义
<select id="queryUserByIdReturnMap" parameterType="int" resultType="map">
select id,user_name as userName,user_pwd as userPwd from user where id=#{id}
</select>
