select的输入和输出
例如 select id,name,age from user where name like '%王%' and age>20
这里既有输入也有输出
select的属性
id,parameterClass,resultClass,parameterMap,resultMap,cacheModel
resultSetType,fetchSize,xmlResultName,remapResults,timeout
输入 parameterClass,ParameterMap
resultSetTYpe为结果集类型,主要是说游标,具有方向性,可以取
forward_only,scoll_insensitive,scoll_sensitive,具体情况具体配置
fetchSize 预取回数据量的大小
xmlResultName,返回result为xml的名称
如果返回的结果可以修改则吧remapResults设为true,否则设为false
输入,用参数带进来
可以是#,$做为占位符
不同占位符使用
<select id="getAllUsers1" resultClass="com.mypackage.User" parameterClass="string"> SELECT * FROM USER WHERE DEPARTMENT=#department# </select> <select id="getAllUsers1" resultClass="com.mypackage.User" parameterClass="string"> SELECT * FROM USER WHERE DEPARTMENT like '$department$' </select>
#不能放在‘’之内
resultMap
<!-- 无映射 --> <select id="getAllUsers1" resultClass="User" parameterClass="string"> SELECT * FROM USER WHERE DEPARTMENT=#department# </select> <!-- 内联映射->实体类 --> <select id="getAllUsers2" resultClass="User" parameterClass="string"> SELECT USERID as userid, USERNAME as username, PASSWORD as password, DEPARTMENT as department FROM USER WHERE DEPARTMENT=#department# </select> <!-- 内联映射->MAP类 --> <select id="getAllUsers3" resultClass="hashmap" parameterClass="string"> SELECT * FROM USER WHERE DEPARTMENT=#department# </select> <!-- 显示映射->实体类 --> <resultMap id="accoutResult" class="User"> <result property="userid" column="USERID" /> <result property="username" column="USERNAME" /> <result property="password" column="PASSWORD" /> <result property="department" column="DEPARTMENT" /> </resultMap> <select id="getAllUsers4" resultMap="accoutResult" parameterClass="string"> SELECT * FROM USER WHERE DEPARTMENT=#department# </select> <!-- 显示映射->MAP类 --> <resultMap id="mapResult" class="hashmap"> <result property="userid" column="USERID" /> <result property="username" column="USERNAME" /> <result property="password" column="PASSWORD" /> <result property="department" column="DEPARTMENT" /> </resultMap> <select id="getAllUsers5" resultMap="mapResult" parameterClass="string"> SELECT * FROM USER WHERE DEPARTMENT=#department# </select>
map映射 ,返回的list里的每一项都是一个map然后有键值对
xml映射
<!-- XML --> <select id="selectXML" parameterClass="string" resultClass="xml" xmlResultName="log"> SELECT * FROM USER_ACCOUNT WHERE GROUPNAME=#groupName# </select>
resultClass="xml"这个xml也是预定义好的类
在测试类里调用后返回的是xml格式的字符串,指定的xmlResultName相当于xml的
根元素
返回结果有三类,1 返回直接指定的类 2 返回map类型 3 返回xml