iBATIS 3 试用手记 - The FUTURE - ITeye技术网站

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iBATIS 3 试用手记 - The FUTURE - ITeye技术网站

前记：本来打算去CSDN写这篇文章的，结果CSDN的服务器又出问题了，登录了N次都进不去，郁闷，干脆换个Blog来写。

 

 　　iBATIS以其对SQL控制的灵活性而受到许多大型项目的青睐，它不像Hibernate那样是完全面向对象的，iBATIS是一个半自动化的O/R Mapping框架。今晚散逛到iBATIS的官网(http://ibatis.apache.org/)，发现iBATIS 3已经到Beta 5阶段，应该说已经比较稳定了，于是Download了一个下来研究，早就听说iBATIS 3在相比iBATIS 2作了很大改动，看来不假，呵呵，废话少说，见下。

　　首先是初始化的改变:

1. Reader reader = Resources.getResourceAsReader(CONFIG_FILE_PATH);  
2. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader, "development_oracle");  
3. SqlSession session = sqlSessionFactory.openSession();  

Reader reader = Resources.getResourceAsReader(CONFIG_FILE_PATH);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader, "development_oracle");
SqlSession session = sqlSessionFactory.openSession();

　　iBATIS 2中的SqlMapClient被SqlSession所替代， 而iBATIS
2中的静态类SqlMapClientBuilder也被SqlSessionFactoryBuilder所替代，变为了非静态的，此外最重要的是
iBATIS
3中需要使用openSession()方法来返回SqlSession的实例，至于上述代码中build方法的第二参数
“development_oracle”是环境配置ID，稍候会讲到。

 

　　下面来看Configuration文件。

1. <?xml version="1.0" encoding="UTF-8"?>  
2. <!DOCTYPE configuration   
3.   PUBLIC "-//ibatis.apache.org//DTD Config 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-config.dtd">  
4.   
5. <configuration>  
6.     <properties resource="conf/database.properties" />  
7.     <environments default="development">  
8.         <environment id="development">  
9.             <transactionManager type="JDBC" />  
10.             <dataSource type="POOLED">  
11.                 <property name="driver" value="${database.driver}"/>  
12.                 <property name="url" value="${database.url}"/>  
13.                 <property name="username" value="${database.user}"/>a  
14.                 <property name="password" value="${database.password}"/>  
15.             </dataSource>  
16.         </environment>  
17.           
18.         <environment id="development_oracle">  
19.             <transactionManager type="JDBC" />  
20.             <dataSource type="POOLED">  
21.                 <property name="driver" value="${oracle.database.driver}"/>  
22.                 <property name="url" value="${oracle.database.url}"/>  
23.                 <property name="username" value="${oracle.database.user}"/>  
24.                 <property name="password" value="${oracle.database.password}"/>  
25.             </dataSource>  
26.         </environment>      
27.     </environments>  
28.       
29.     <mappers>  
30.         <mapper resource="conf/NewsNotice.xml"/>  
31.     </mappers>  
32. </configuration>   

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
  PUBLIC "-//ibatis.apache.org//DTD Config 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-config.dtd">

<configuration>
	<properties resource="conf/database.properties" />
	<environments default="development">
		<environment id="development">
			<transactionManager type="JDBC" />
			<dataSource type="POOLED">
				<property name="driver" value="${database.driver}"/>
				<property name="url" value="${database.url}"/>
				<property name="username" value="${database.user}"/>a
				<property name="password" value="${database.password}"/>
			</dataSource>
		</environment>

		<environment id="development_oracle">
			<transactionManager type="JDBC" />
			<dataSource type="POOLED">
				<property name="driver" value="${oracle.database.driver}"/>
				<property name="url" value="${oracle.database.url}"/>
				<property name="username" value="${oracle.database.user}"/>
				<property name="password" value="${oracle.database.password}"/>
			</dataSource>
		</environment>
	</environments>

	<mappers>
		<mapper resource="conf/NewsNotice.xml"/>
	</mappers>
</configuration> 

    database.properties内容：

1. database.driver = org.gjt.mm.mysql.Driver  
2. database.url = jdbc:mysql://localhost:3306/test  
3. database.user = root  
4. database.password = root  
5.   
6. oracle.database.driver = oracle.jdbc.driver.OracleDriver  
7. oracle.database.url = jdbc:oracle:thin:@locahost:1521:ORCL2  
8. oracle.database.user = Tester  
9. oracle.database.password = password  

database.driver = org.gjt.mm.mysql.Driver
database.url = jdbc:mysql://localhost:3306/test
database.user = root
database.password = root

oracle.database.driver = oracle.jdbc.driver.OracleDriver
oracle.database.url = jdbc:oracle:thin:@locahost:1521:ORCL2
oracle.database.user = Tester
oracle.database.password = password

　　本人觉得iBATIS 3配置文件最大的变化是增加了<environment/>标签，这样对于不同的环境可以配置不同的属性，无论从开发还是布署都显得非常方便。

　　iBATIS
3提供了2种transactionManager类型，分别为JDBC和MANAGED，如果设定为MANAGED，则将整个Transaction的
生命周期交由J2EE Container管理；至于JDBC就不用说了吧，这个地球人都晓得的:-D

　　至于Datasource的类型，iBATIS 3提供了UNPOOLED、POOLED和JNDI三种方式，

• UNPOOLED：不使用连接池连接Database，每次请求时Open Connection，结束时Close Connection；
• POOLED：以池化方式连接Database，它有许多属性可供设置，像poolMaximumActiveConnections、
  poolMaximumIdleConnections、poolMaximumCheckoutTime、poolPingQuery等等；
• JNDI：在J2EE Container中配置Datasource。

　　<Mapper>标签指定要使用的Mapping文件。

 

　　下面来看Mapping文件内容，这是iBATIS 3改动最多的地方。

 

1. <?xml version="1.0" encoding="UTF-8"?>  
2. <!DOCTYPE mapper    
3.     PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd">  
4.   
5. <mapper namespace="NewsNotice">  
6.     <resultMap type="org.newsnotice.domain.NewsNoticeModel" id="resultMap-getNewsNotice1">  
7.         <id column="NN_ID" property="id" />  
8.         <result column="CATEGORY" property="category" />  
9.         <result column="SUBJECT" property="subject" />  
10.         <result column="POSTED_DATE" property="postedDate" />  
11.         <result column="EXPIRY_DATE" property="expiryDate" />  
12.         <result column="ALERT" property="alert" />  
13.         <result column="EMAIL_ALERT" property="emailAlert" />  
14.         <result column="AUDIENCE" property="audience" />  
15.         <result column="FILTER" property="filter" />  
16.         <result column="FILTER_VALUE" property="filterValue" />  
17.         <result column="SUB_FILTER_VALUE" property="subFilterValue" />  
18.         <result column="EXCLUDE_USER_ID" property="excludeUserId" />  
19.         <result column="WF_DEPARTMENT" property="department" />  
20.         <result column="WF_STATUS" property="status" />  
21.         <result column="WF_NOTES" property="notes" />  
22.         <result column="DEFUNCT_IND" property="defunctInd" />  
23.         <result column="APPROVER" property="approver" />  
24.         <association property="newsNoticeContent" column="CONTENT_ID" javaType="org.newsnotice.domain.NewsNoticeContentModel">  
25.             <id column="CONTENT_ID" property="id" />  
26.             <result column="PARENT_NN_ID" property="parentId" />  
27.             <result column="CONTENT" property="content" />  
28.         </association>  
29.         <collection property="newsNoticeMsgBoxList" ofType="org.newsnotice.domain.NewsNoticeMsgBoxModel" >  
30.             <id column="MSG_BOX_ID" property="id"/>  
31.             <result column="USER_ID" property="userId" />  
32.             <result column="MSG_BOX_NN_ID" property="nnId" />  
33.             <result column="FOLDER" property="folder" />  
34.             <result column="READ" property="read" />            
35.             <result column="READ_ON" property="readOn" />  
36.             <result column="MSG_BOX_DEFUNCT_IND" property="defunctInd" />  
37.             <result column="MSG_BOX_PI_NO" property="piNo" />  
38.         </collection>  
39.     </resultMap>  
40.       
41.     <select id="getNewsNotice" parameterType="org.newsnotice.domain.NewsNoticeModel" resultMap="resultMap-getNewsNotice1" >  
42.         SELECT A.NN_ID, A.CATEGORY, A.SUBJECT, A.POSTED_DATE, A.EXPIRY_DATE, A.ALERT, A.EMAIL_ALERT, A.AUDIENCE,  
43.             A.FILTER, A.FILTER_VALUE, A.SUB_FILTER_VALUE, A.EXCLUDE_USER_ID, A.WF_DEPARTMENT, A.WF_STATUS, A.WF_NOTES,  
44.             A.DEFUNCT_IND, A.APPROVER, B.ID CONTENT_ID, B.PARENT_NN_ID, B.CONTENT, C.ID MSG_BOX_ID, C.USER_ID,   
45.             C.NN_ID MSG_BOX_NN_ID, C.FOLDER, C.READ, C.READ_ON, C.DEFUNCT_IND MSG_BOX_DEFUNCT_IND, C.PI_NO MSG_BOX_PI_NO  
46.         FROM NN_MSTR A, NN_CONTENT B, NN_MSG_BOX C  
47.         WHERE A.NN_ID = B.PARENT_NN_ID  
48.         AND A.NN_ID = C.NN_ID  
49.         <if test="id != null">  
50.             AND A.NN_ID = #{id}  
51.         </if>  
52.         <if test="category != null">  
53.             AND A.CATEGORY = #{category}  
54.         </if>  
55.         <if test="status != null">  
56.             AND A.WF_STATUS = #{status}  
57.         </if>  
58.     </select>  

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
    PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd">

<mapper namespace="NewsNotice">
	<resultMap type="org.newsnotice.domain.NewsNoticeModel" id="resultMap-getNewsNotice1">
		<id column="NN_ID" property="id" />
		<result column="CATEGORY" property="category" />
		<result column="SUBJECT" property="subject" />
		<result column="POSTED_DATE" property="postedDate" />
		<result column="EXPIRY_DATE" property="expiryDate" />
		<result column="ALERT" property="alert" />
		<result column="EMAIL_ALERT" property="emailAlert" />
		<result column="AUDIENCE" property="audience" />
		<result column="FILTER" property="filter" />
		<result column="FILTER_VALUE" property="filterValue" />
		<result column="SUB_FILTER_VALUE" property="subFilterValue" />
		<result column="EXCLUDE_USER_ID" property="excludeUserId" />
		<result column="WF_DEPARTMENT" property="department" />
		<result column="WF_STATUS" property="status" />
		<result column="WF_NOTES" property="notes" />
		<result column="DEFUNCT_IND" property="defunctInd" />
		<result column="APPROVER" property="approver" />
		<association property="newsNoticeContent" column="CONTENT_ID" javaType="org.newsnotice.domain.NewsNoticeContentModel">
			<id column="CONTENT_ID" property="id" />
			<result column="PARENT_NN_ID" property="parentId" />
			<result column="CONTENT" property="content" />
		</association>
		<collection property="newsNoticeMsgBoxList" ofType="org.newsnotice.domain.NewsNoticeMsgBoxModel" >
			<id column="MSG_BOX_ID" property="id"/>
			<result column="USER_ID" property="userId" />
			<result column="MSG_BOX_NN_ID" property="nnId" />
			<result column="FOLDER" property="folder" />
			<result column="READ" property="read" />
			<result column="READ_ON" property="readOn" />
			<result column="MSG_BOX_DEFUNCT_IND" property="defunctInd" />
			<result column="MSG_BOX_PI_NO" property="piNo" />
		</collection>
	</resultMap>

	<select id="getNewsNotice" parameterType="org.newsnotice.domain.NewsNoticeModel" resultMap="resultMap-getNewsNotice1" >
		SELECT A.NN_ID, A.CATEGORY, A.SUBJECT, A.POSTED_DATE, A.EXPIRY_DATE, A.ALERT, A.EMAIL_ALERT, A.AUDIENCE,
			A.FILTER, A.FILTER_VALUE, A.SUB_FILTER_VALUE, A.EXCLUDE_USER_ID, A.WF_DEPARTMENT, A.WF_STATUS, A.WF_NOTES,
			A.DEFUNCT_IND, A.APPROVER, B.ID CONTENT_ID, B.PARENT_NN_ID, B.CONTENT, C.ID MSG_BOX_ID, C.USER_ID,
			C.NN_ID MSG_BOX_NN_ID, C.FOLDER, C.READ, C.READ_ON, C.DEFUNCT_IND MSG_BOX_DEFUNCT_IND, C.PI_NO MSG_BOX_PI_NO
		FROM NN_MSTR A, NN_CONTENT B, NN_MSG_BOX C
		WHERE A.NN_ID = B.PARENT_NN_ID
		AND A.NN_ID = C.NN_ID
		<if test="id != null">
			AND A.NN_ID = #{id}
		</if>
		<if test="category != null">
			AND A.CATEGORY = #{category}
		</if>
		<if test="status != null">
			AND A.WF_STATUS = #{status}
		</if>
	</select>

　　先说动态SQL，这是iBATIS最强大的地方，如果熟悉iBATIS
2的话，一眼可以看出没有了<isNotNull>、<isNotEmpty>、<isLessThan>等熟悉的
标签，不错，iBATIS使用了类似JSTL的标
签<if>、<choose>、<when>、<otherwise>、<foreach>
等来代替原来的标签，并且传值方式由#property name#, $property name$变为了#{property
name}和${property name}，就我个人而言，这些标签感觉没有iBATIS2用上去爽。

　　此外根元素<mapper>的属性namespace在iBATIS 3中是required，而不像iBATIS 2中是可选的，可要可不要。

　　下面来说说新增元素<association>和<collection>，<association>
对应于Java中的Has
A模型，也可以理解为数据库中一对一关系，拿上述例子来说，每条消息的概要信息与消息内容是分别存放在两张Table中的，可以通过上述方法一次性将其取
出来，而不需要执行多次查询。而<collection>有点类型主从表关系，即one-to-many模型。

　　查询标签<select>也有所改变，首先是属性名称，由原来的parameterClass改为了
parameterType，resultClass与变为了resultType，此外需要注意的是如果传入的参数类型为复杂对象，如Bean，则需要
在参数后面加上jdbcType属性来指定对应数据库表列的类型，如#{userName,
jdbcType=VARCHAR}，如果传入的是基本类型，像int,long之类的，则不需要指定。

　　另外的变化就是执行方法上的变化，使用select, selectOne, selectList等替代了原来的方法，大家可以参考其API，我在些就不多说了。

来自为知笔记(Wiz)