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：

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

• <!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。