MyBatis SqlSessionFactory的几种常见创建方式

原文链接：https://blog.csdn.net/jimolangge123/article/details/49228255

MyBatis框架主要是围绕着SqlSessionFactory这个类进行的，这个的创建过程如下：

1. 定义一个Configuration对象，其中包含数据源、事务、mapper文件资源以及影响数据库行为属性设置settings
2. 通过配置对象，则可以创建一个SqlSessionFactoryBuilder对象
3. 通过 SqlSessionFactoryBuilder 获得SqlSessionFactory 的实例。
4. SqlSessionFactory 的实例可以获得操作数据的SqlSession实例，通过这个实例对数据库进行操作

具体看看SqlSessionFactory的创建

一、通过Configuration.xml配置文件进行创建

  1.配置文件：

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<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration>     <properties resource="ssm/jdbc.properties"></properties>     <environments default="development">         <environment id="development">             <transactionManager type="JDBC" />             <dataSource type="POOLED">                 <property name="driver" value="${jdbc.driverClassName}"/>                 <property name="url" value="${jdbc.url}"/>                 <property name="username" value="${jdbc.username}"/>                 <property name="password" value="${jdbc.password}"/>             </dataSource>         </environment>     </environments>             <mappers>         <mapper resource="ssm/BlogMapper.xml"/>     </mappers> </configuration>

2.读取配置文件：

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package ssm;   import java.io.IOException; import java.io.Reader;   import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder;   import com.sm.model.User;   public class GetSqlSessionFactoryFromXML {       public static void main(String[] args) throws IOException {         //配置文件的名称         String resource = "ssm/configuration.xml";         //通过Mybatis包中的Resources对象很轻松的获取到配置文件         Reader reader = Resources.getResourceAsReader(resource);         //通过SqlSessionFactoryBuilder创建         SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);         //获得session实例         SqlSession session =sqlSessionFactory.openSession();         User user = new User();         user.setId(8);         //完成数据库的插入         session.insert("add", user);         session.commit();         session.close();         System.out.println(sqlSessionFactory);     } }

二、在程序中构建这些对象来创建

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package ssm;   import java.sql.SQLException; import javax.sql.DataSource; import org.apache.ibatis.datasource.pooled.PooledDataSource; import org.apache.ibatis.mapping.Environment; import org.apache.ibatis.session.Configuration; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import org.apache.ibatis.transaction.TransactionFactory; import org.apache.ibatis.transaction.jdbc.JdbcTransactionFactory; import com.sm.model.User;   public class GetSqlSessionFactoryFromProgram {       public static void main(String[] args) throws SQLException {         String driver = "oracle.jdbc.OracleDriver";         String url = "jdbc:oracle:thin:@localhost:1521:orcl";         String username="scott";         String password="tiger";         //创建使用缓存池的数据源         /*          * <dataSource type="POOLED">                 <property name="driver" value="${jdbc.driverClassName}"/>                 <property name="url" value="${jdbc.url}"/>                 <property name="username" value="${jdbc.username}"/>                 <property name="password" value="${jdbc.password}"/>             </dataSource>          */         DataSource dataSource =new PooledDataSource(driver,url,username,password);                   //创建事务         /*          * <transactionManager type="JDBC" />          */         TransactionFactory transactionFactory =  new JdbcTransactionFactory();                   Environment environment = new Environment("development", transactionFactory, dataSource);                   Configuration configuration = new Configuration(environment);         //加入资源         /*          * <mapper resource="ssm/BlogMapper.xml"/>          */         configuration.addMapper(UserMapper.class);         SqlSessionFactory sqlSessionFactory = new  SqlSessionFactoryBuilder().build(configuration);         System.out.println(sqlSessionFactory);                   SqlSession session =  sqlSessionFactory.openSession();         User user = new User();         user.setId(6);         session.insert("add", user);         session.commit();         session.close();     } }

三、通过与Spring集成，由Spring容器管理创建

1. 在spring的配置文件applicationContext.xml中配置

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<bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">        <property name="dataSource" ref="dataSource" />        <property name="configLocation" value="classpath*:conf/configuration.xml"/>       </bean>

如果使用则直接注入，获取SqlSessionFactory实例即可。