mapper.xml配置文件详解

<mapper namespace="com.harbsoft.com.mybatis.mapper.UserMapper">

<cache type="org.mybatis.caches.ehcache.EhcacheCache" />

<sql id="user_query_where">
通用sql
</sql>

<if test="id!=null and id!=''">
通常是where条件语句
</if>

<foreach collection="ids" item="id" open="and (" close=")" separator="or">
user.id=#{id}
</foreach>

AND user.username LIKE '${username}%'

AND user.sex = #{sex}

<resultMap type="person" id="resultMapPerson">
<!-- 结果集的主键 -->
--主键  <id/>
<id  property="userid" column="id"/>
<!-- 普通的列 -->
--column 是数据库中字段， property是实体类中字段
<result property="name"  column="username" />
<result property="addr"  column="address" />
</resultMap>

<association property="user" javaType="com.harbosoft.mybatis.po.User">
<id  property="id" column="user_id"/>
<result  property="username" column="username"/>
<result  property="sex" column="sex"/>
<result  property="address" column="address"/>
</association>

<!-- 订单信息 -->
<collection property="orders" ofType="com.harbosoft.mybatis.po.Orders">
<!-- 订单号 -->
<result property="order_number" column="order_number" />
<result property="id" column="id" />
</collection>

public User findUserById(int id)

<select id="findUserById" parameterType="int"  resultType="user">
SELECT * FROM USER WHERE id=#{id}
<!--
id-------mapper接口的方法名；
parameterType -------mapper接口的方法参数的类型
resultType ---------mapper接口的方法的返回值类型
user ----------是别名（全名是com.harbosoft.mybatis.Items）
id 和形参保持一致   （#）
-->
</select>

public List<User> findUserByName(String username)

<select id="findUserByName" parameterType="string" resultType="user">
SELECT * FROM USER WHERE username like '${value}%'
<!--
该方法返回值类型为List，但是集合中装的是user，所以resultType 的值只要和集合中存储的一样即可
value 可以随意些，什么都可以  （$）
-->
</select>

public List<User> findUserList(User user)throws Exception;

<!-- 综合查询用户信息 -->
<select id="findUserList" parameterType="user" resultType="user">
SELECT * FROM USER
<where>
<!-- 用户的查询条件 -->
<include refid="user_query_where"/>
<!--该条SQL可能会重用，所以抽取出来，引用时用include-->
</where>
</select>

<sql id="user_query_where">
<if test="id!=null and id!=''">
AND user.id=#{id}
</if>

<foreach collection="ids" item="id" open="and (" close=")" separator="or">
user.id=#{id} and (userid =
</foreach>
<if test="username!=null and username!=''">
AND user.username LIKE '${username}%'
</if>
<if test="sex!=null and sex!=''">
AND user.sex = #{sex}
</if>
</sql>

public List<Person> findUserListResultMap(User user)throws Exception;

<!-- 综合查询用户信息 使用resultMap-->
<select id="findUserListResultMap" parameterType="user" resultMap="resultMapPerson">
SELECT * FROM USER WHERE username like '${username}%' and sex=#{sex}
</select>

public List<User> findUserListByHashmap(Map map)throws Exception;

<!-- 通过hashmap查询用户信息 -->
<select id="findUserListByHashmap" parameterType="hashmap" resultType="user">
SELECT * FROM USER WHERE username like '${name}%' and sex=#{sex}
</select>

public Map findUserByIdReturnMap(int id) throws Exception;

<!-- 获取单个用户信息返回hashmap -->
<select id="findUserByIdReturnMap" parameterType="int"  resultType="hashmap">
SELECT * FROM USER WHERE id=#{id}
</select>

public void insertUser(User user) throws Exception;

<insert id="insertUser" parameterType="user">
<!--
keyProperty：指定主键映射的pojo对象的属性
order：selectKey的执行顺序，mysql这里设置为after
企业中实际使用时，主键通常使用uuid()即 SELECT UUID()
-->
<selectKey keyProperty="id" order="AFTER" resultType="int">
SELECT LAST_INSERT_ID()
</selectKey>

INSERT INTO USER(username,birthday,sex,address,detail,score)
VALUES(#{username},#{birthday},#{sex},#{address},#{detail},#{score})
</insert>

public void updateUserById(User user) throws Exception;

<update id="updateUserById"  parameterType="com.harbsoft.mybatis.po.User">
update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address},detail=#{detail},score=#{score}
where id=#{id}
</update>

public void deleteUserById(int id) throws Exception;

<delete id="deleteUserById"  parameterType="java.lang.Integer">
delete from user where id=#{value}
</delete>