MyBatis SqlSessionFactory的几种常见创建方式

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：

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
通过配置对象，则可以创建一个SqlSessionFactoryBuilder对象
通过 SqlSessionFactoryBuilder 获得SqlSessionFactory 的实例。
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

<!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>

代码实现

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

代码实现

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

在spring的配置文件applicationContext.xml中配置

<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。