MyBatis-opensession

创建sqlsession经过了以下几个主要步骤：1)       从配置中获取Environment；2)       从Environment中取得DataSource；3)       从Environment中取得TransactionFactory；4)       从DataSource里获取数据库连接对象Connection；5)       在取得的数据库连接上创建事务对象Transaction；6)       创建Executor对象（该对象非常重要，事实上sqlsession的所有操作都是通过它完成的）；7)       创建sqlsession对象。SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is); SqlSession session = factory.openSession(); SqlSession接口 类：  DefaultSqlSessionFactory--> private final org.apache.ibatis.session.Configuration                              configuration;                          --> public DefaultSqlSessionFactory                              (org.apache.ibatis.session.Configuration configuration)                           --> public org.apache.ibatis.session.SqlSession                                openSession()-->openSession(boolean b);  SqlSessionManager-->startManagedSession                   -->public org.apache.ibatis.session.SqlSession                    openSession(boolean autoCommit) -->openSession()解析完配置文件之后，配置文件中的所有信息就存储到了Configuration对象中了，在创建SqlSessionFactory对象时将Configuration做为SqlSessionFactory对象的一个属性，通过调用SqlSessionFactory的openSession(...)，openSession()有很多重载方法，创建SqlSession对象只能通过openSession()和这些重载方法@Override  public SqlSession openSession() {    return openSessionFromDataSource(configuration.getDefaultExecutorType(), null, false);  }  底层代码：//IntelliJ API Decompiler stub source generated from a class file从类文件生成的intellij存根源文件//Implementation of methods is not available无法实现方法package org.apache.ibatis.session;public interface SqlSessionFactory {    org.apache.ibatis.session.SqlSession openSession();    org.apache.ibatis.session.SqlSession openSession(boolean b);    org.apache.ibatis.session.SqlSession openSession(java.sql.Connection connection);    org.apache.ibatis.session.SqlSession openSession(org.apache.ibatis.session.TransactionIsolationLevel transactionIsolationLevel);    org.apache.ibatis.session.SqlSession openSession(org.apache.ibatis.session.ExecutorType executorType);    org.apache.ibatis.session.SqlSession openSession(org.apache.ibatis.session.ExecutorType executorType, boolean b);    org.apache.ibatis.session.SqlSession openSession(org.apache.ibatis.session.ExecutorType executorType, org.apache.ibatis.session.TransactionIsolationLevel transactionIsolationLevel);    org.apache.ibatis.session.SqlSession openSession(org.apache.ibatis.session.ExecutorType executorType, java.sql.Connection connection);    org.apache.ibatis.session.Configuration getConfiguration();}