在數據庫持久層的框架中,大家一定聽過Hibernate的大名了吧,經典的SSH框架就有它的一份哦!可是我今天要說的卻是另外一個持久層的框架,它就是iBatis。與Hibrenate相比,它的主要優勢就是簡單、小巧、輕量級,但是它的功能卻絲毫不亞於 Hibernate,下面讓我們來看看iBatis在項目中的應用吧!
<sqlMap namespace="admin">在運用時如下:
this.getSqlMapClient().update(“admin.update”, entity);
分析:
ibatis 配置文件中的useStatementNamespaces:是否使用Statement命名空間。這裏的命名空間指的是映射文件中,sqlMap節點的 namespace屬性,如:<sqlMap namespace="User">。這裏,指定了此sqlMap節點下定義的操作均從屬於"User"命名空間。
在 useStatementNamespaces="true"的情況下,Statement調用需追加命名空間,如:sqlMap.update("User.updateUser",user);否則直接通過Statement名稱調用即可,如:sqlMap.update("updateUser",user);
好處:
在實際應用中,利用namespace可以防止兩個同名的方法而引起衝突。如有兩個updateUser,可以通過A updateUser/B. updateUser來區分。
另一種方法:
但有一種更方便的方法,可以在不採用namspace的情況下,解決上面的問題:即直接在方法的前面直接命名爲A updateUser/B. updateUser。調用時,直接調用A updateUser/B. updateUser即可。如下:
<sqlMap>
<typeAlias type="com.admin.entity.Admin" alias="Admin" />
<select id="Admin.findUserByLoginName" parameterClass="java.lang.String"
resultMap="AdminResult">
select * from T_ADMINISTRATORS where longinName = #value#
and status != 4
</select>
調用時,getSqlMapClientTemplate.queryForList(“Admin.findUserByLoginName”,”test”);即可。
請注意:
此時需要保證所有映射文件中,Statement定義無重名。
第二:
resultMap:結果映射,需結合resultMap節點對映射關係加以定義。
<sqlMap>
<typeAlias type="com.admin.entity.Admin" alias="Admin" />
<resultMap id="AdminResult" class="Admin">
<result column="staff_id" property="id" />
<result column="loginName" property="loginName" />
<result column="password" property="password" />
<result column="staff_name" property="username" />
<result column="status" property="status" />
<result column="phone" property="phone" />
<result column="email" property="email" />
</resultMap>
<select id="Admin.findUserByLoginName" parameterClass="java.lang.String"
resultMap="AdminResult">
select * from T_ADMINISTRATORS where longinName = #value#
and status != 4
</select>
</sqlMap>
resultclass/resultMap的類型大都是:對象/hashmap
當parameterClass/resultMap的類型是對象時,用#屬性#表示。程序會調用JAVABEAN的getter方法,進行獲取屬性值。
當parameterClass/resultMap的類型是hashmap(Map是key-value結構的)時,那程序會直接通過key來分析取參數。
<select id="select1" parameterClass="java.lang.String" resultClass="AppLog">
select
ID as id,
TYPE as type,
DESCR as descr
from APP_LOG
where ID = #id#
</select>
sqlMapper.queryForObject("select0", id);
Map類參數
<select id="select2" parameterClass="java.util.HashMap" resultClass="AppLog">
select
ID as id,
TYPE as type,
DESCR as descr
from APP_LOG
where ID = #ids#
</select>
map.put("ids", id);
AppLog log = (AppLog) sqlMapper.queryForObject("select0", map);
對象參數
<select id="select3" parameterClass="AppLog" resultClass="AppLog">
select
ID as id,
TYPE as type,
DESCR as descr
from APP_LOG
where ID = #id#
</select>
AppLog p=new AppLog();
p.setId(id);
AppLog log = (AppLog) sqlMapper.queryForObject("select3", p);
<select id="selectd" resultClass="java.util.HashMap" parameterClass="java.util.HashMap"
select $fieldList$
from $table$
where ID = #id#
</select>
Map p = new HashMap();
p.put("id", id);
p.put("table","APP_LOG");
p.put("fieldList", "ID,TYPE,DESCR");
Map map = (Map) sqlMapper.queryForObject("selectd", p);
String id1 = (String) map.get("ID");
String type = (String) map.get("TYPE");
String descr = (String) map.get("DESCR");
1.#是把傳入的數據當作字符串,如#field#傳入的是id,則sql語句生成是這樣,order by "id",這當然會報錯..
2.$傳入的數據直接生成在sql裏,如#field#傳入的是id,則sql語句生成是這樣,order by id, 這就對了.
$方式一般用於傳入數據庫對象.例如傳入表名.
別名映射->實體類 + resultClass
<select id=" selectAll" resultClass="AppLog">
select
ID as id,
TYPE as type,
DESCR as descr
from APP_LOG
where ID = #id#
</select>
List list = sqlMapper.queryForList("selectAll");
for (int i = 0; i < list.size(); i ) {
AppLog log = (AppLog) list.get(i);
//add your code here;
}
注意:
爲什麼定義了resultClass="AppLog",而queryForList出來的是list?
這裏的resultClass="AppLog",是指查詢出來的每條記錄的格式是AppLog。
當我們queryForList時,系統會將各條記錄(即各個AppLog放到list中)傳回給我們。當我們queryForObject時,就只傳回一個AppLog。
別名映射->Map類+resultClass --》把每條記錄放於map中,字段名爲key,值爲value.
<select id=" selectAll" resultClass="java.util.HashMap">
select
ID as id,
TYPE as type,
DESCR as descr
from APP_LOG
where ID = #id#
</select>
List list = sqlMapper.queryForList("selectAll");
for (int i = 0; i < list.size(); i ) {
Map map = (Map) list.get(i);
String id = (String) map.get("id");
String type = (String) map.get("type");
String descr = (String) map.get("descr");
//add your code here;
}
<select id="selectAll3" resultClass="java.util.HashMap">
select * from APP_LOG
</select>
List list = sqlMapper.queryForList("selectAll3");
for (int i = 0; i < list.size(); i ) {
Map map = (Map) list.get(i);
String id = (String) map.get("ID");
String type = (String) map.get("TYPE");
String descr = (String) map.get("DESCR");
}
顯式映射->實體類:resultMap
<resultMap id="AppLogResult" class="AppLog">
<result property="id" column="ID"/>
<result property="type" column="Type"/>
<result property="descr" column="DESCR"/>
</resultMap>
<select id="selectAll" resultMap="AppLogResult">
select * from APP_LOG
</select>
List list = sqlMapper.queryForList("selectAll");
for (int i = 0; i < list.size(); i ) {
AppLog log = (AppLog) list.get(i);
//add your code here;
}
顯式映射->Map類:resultMap --》把每條記錄放於map中,字段名爲key,值爲value.
<resultMap id="map-result" class="java.util.HashMap">
<result property="id" column="ID"/>
<result property="type" column="Type"/>
<result property="descr" column="DESCR"/>
</resultMap>
<select id="selectAll2" resultMap="map-result">
select * from APP_LOG
</select>
List list = sqlMapper.queryForList("selectAll2");
for (int i = 0; i < list.size(); i ) {
Map map = (Map) list.get(i);
String id = (String) map.get("id");
String type = (String) map.get("type");
String descr = (String) map.get("descr");
}
map.put("appIds", Ids);
executor.update("Device.OpenClientApp", map);
下面的property屬性及循環變量,都是對應map的key名。
-----證明,ibatis對於hashmap,都是通過key來獲取值的。所以,所有參數須用key來表示!!!
如下:
<update id="Device.OpenClientApp" parameterClass="java.util.HashMap">
update T_Device_App_R_Info set Opr='1' where App_ID in
<iterate conjunction="," open="(" close=")" property="appIds">
#appIds[]#
</iterate>
</update>
<statement id=”statementName” parameterClass=” examples.domain.Product”>
insert into PRODUCT values (#id#, #description#, #price#, #classify.id#)
</statement>
<insert id="insertUser7" parameterClass="user">
<![CDATA[
INSERT INTO t_user ( ID, NAME, PASS )VALUES( #id#,#name#,#pass# )
]]>
</insert>
二,內聯參數映射:
<insert id="insertUser8" parameterClass="user">
<![CDATA[
INSERT INTO t_user ( ID, NAME, PASS ) VALUES( #id:INT#, #name:VARCHAR#, #pass:VARCHAR# )
]]>
</insert>
三,外聯參數映射:
<parameterMap id="parameterMap" class="user">
<parameter property="id" jdbcType="INTEGER" />
<parameter property="name" jdbcType="VARCHAR" />
<parameter property="pass" jdbcType="VARCHAR" />
</parameterMap>
<insert id="insertUser9" parameterMap="parameterMap">
<![CDATA[
INSERT INTO t_user ( ID, NAME, PASS )VALUES( ?,?,? )
]]>
</insert>
- String[] ids;
- ...........
- map.put("devId", ids[0]);
- map.put("appId", ids[1]);
- <!-- 自動參數映射方式 -->
- <insert id="DAPermit.addAppDevMapping" parameterClass="java.util.HashMap">
- insert into T_Device_App_R_Info(Device_ID,App_ID,Opr) values (#devId#,#appId#,'2');
- </insert>
- <!--
- 內聯方式:
- <insert id="DAPermit.addAppDevMapping" parameterClass="java.util.HashMap">
- insert into T_Device_App_R_Info(Device_ID,App_ID,Opr) values (#devId:varchar#,#appId:varchar#,'2');
- </insert>
- 外聯方式:
- <parameterMap id="dapermitParams" class="java.util.HashMap">
- <parameter property="devId" jdbcType="VARCHAR"/>
- <parameter property="appId" jdbcType="VARCHAR"/>
- </parameterMap>
- <insert id="DAPermit.addAppDevMapping" parameterMap="dapermitParams">
- insert into T_Device_App_R_Info(Device_ID,App_ID,Opr) values (?,?,'2');
- </insert>
- -->
- <!-- example 11: 存儲過程 -->
- <resultMap id="returnResultMap" class="user">
- <result property="id" column="ID" />
- </resultMap>
- <parameterMap id="paramUser" class="java.util.Map">
- <parameter property="name" jdbcType="VARCHAR" javaType="string" mode="IN" />
- <parameter property="pass" jdbcType="VARCHAR" javaType="string" mode="IN" />
- <parameter property="id" jdbcType="INT" javaType="Integer" mode="INOUT" resultMap="returnResultMap" />
- </parameterMap>
- <procedure id="pro_insertUser11" parameterMap="paramUser" resultClass="int">
- <![CDATA[
- {call proc_userinsert(?,?,?)}
- ]]>
- </procedure>
- 然後在UserDaoTest.java中增加如下一個方法:
- public static void example11() throws Exception {
- try {
- Map map = new HashMap();
- map.put("name", "procedure");
- map.put("pass", "123456");
- Integer returnValue = (Integer)sqlMapClient.insert("pro_insertUser11", map);
- System.out.println(returnValue);
- } catch (Exception e) {
- e.printStackTrace();
- }
- }