mybatis中的mapper

　　插入后返回主键、关联查询、多参

xml格式

插入后返回主键

“keyProperty”表示返回的 id 要保存到对象的那个属性中，“useGeneratedKeys”表示主键 id 为自增长

<insert id="insertUser" parameterType="com.hfy.db.bean.User" useGeneratedKeys="true" keyProperty="id">
</insert>

数据库为 Oracle 时

<insert id="insert" parameterType="com.test.User">
  <selectKey resultType="INTEGER" order="BEFORE" keyProperty="userId">
    SELECT SEQ_USER.NEXTVAL as userId from DUAL
  </selectKey>
  insert into user (user_id, user_name, modified, state)
  values (#{userId,jdbcType=INTEGER}, #{userName,jdbcType=VARCHAR},
  #{modified,jdbcType=TIMESTAMP}, #{state,jdbcType=INTEGER})
</insert>

由于 Oracle 没有自增长一说法，只有序列这种模仿自增的形式，所以不能再使用“useGeneratedKeys”属性。而是使用将 ID 获取并赋值到对象的属性中，insert 插入操作时正常插入 id

多个参数

　　对于接口中多个请求参数，没有封装成对象

// dao中:
OrderDetail selectByTypeAndDate(@Param("type")Integer type, @Param("date")String date);
// mapper中：
<select id="selectByTypeAndDate" resultMap="orderDetailResult" >
    SELECT * FROM order_detail
    WHERE type = #{type}
    <c:if test="type == 1">
      and minPlayTime > #{date}
    </c:if>
    <c:if test="type == 2">
      and maxPlayTime < #{date}
    </c:if>
</select>

关联查询　　

<resultMap type="com.hfy.db.bean.Order" id="OrderResult">
    <result property="id" column="id" />
    <!-- 配置关联关系 -->
    <association property="user" column="userId"
      select="com.hfy.dao.UserDao.selectById"></association>
  </resultMap>

MyBatis参数传入集合之foreach动态sql http://blog.csdn.net/small____fish/article/details/8029030/

注解格式

插入后返回主键

@Insert("")
@SelectKey(statement = "SELECT LAST_INSERT_ID()", keyProperty = "user.id", resultType = int.class, before = false)

MyBatis注解select in参数

/**
 *
 * @param ids '1,2,3'
 * @return
 */
@Select("select * from user where id in (${ids})")
List<UserInfo> getUserbyIds(@Param("ids")String ids);

MyBatis注解list参数

注解中想使用xml中的<if>标签，需要用<script>标签将其包起来

<script>
insert into tb_image_temp(
    <foreach collection='keys' item='item' open='(' separator=',' close=')'>
        ${item}
    </foreach>

) values(
    <foreach collection='values' item='item' open='(' separator=',' close=')'>
        #{item}
    </foreach>
)
</script>

MyBatis注解map参数

@Update("<script>\n" +
            "    update ${tableName} set " +
            "            <foreach collection='map'  index='key' item='item' open='' separator=',' close='' >\n" +
            "                ${key} = #{item}\n" +
            "            </foreach>\n" +
            "    where id = #{id}\n" +
            "</script>")
void updateImage(@Param("tableName") String tableName, @Param("map") Map<String, Object> map, @Param("id") Integer id);

结果映射

@Select("")
@Results({
        @Result(property ="groupId",column = "groupId"),
        //查询关联对象
        @Result(property = "adminGroup",
                column = "groupId",
                one = @One(select = "com.cyf.db.mapper.AdminGroupMapper.getGroupById")
        )
})
List<ManageAccount> getManageAccount(@Param("manageAccount") ManageAccount manageAccount);