完整的时序图可以打开我的云笔记进行查看，对浏览器查看比例进行缩放为250%即可
1 Mybatis操作主体流程
- 定位配置文件的位置
- 构建sessionFactory
- 获取数据库操作会话
- 建立数据库连接并执行数据库操作
1.1 定位配置文件位置
使用org.apache.ibatis.io.Resources.getResourceAsReader(String)定位mybatis配置文件的位置，获得文件的输入流。
Created with Raphaël 2.1.0ReaderReaderResourcesResourcesInputStreamReaderInputStreamReaderInputStreamInputStreamClassLoaderWrapperClassLoaderWrapperClassLoaderClassLoadergetResourceAsReader()getResourceAsReader()''getResourceAsStream()getResourceAsStream()getResourceAsStream()''getResourceAsReadernew InputStreamReader()
1.2构建SqlSessionFactory
构建SqlSessionFactory的时序图,使用SqlSessionFactoryBuilder创建SqlSessionFactory对象
Created with Raphaël 2.1.0SqlSessionFactoryBuilderSqlSessionFactoryBuilderXMLConfigBuilderXMLConfigBuilderXPathParserXPathParserDocumentBuilderDocumentBuilderDOMParserDOMParserDocumentDocumentConfigurationConfigurationSqlSessionFactorySqlSessionFactorybuild(reader)XMLConfigBuilder(XPathParser)createDocument()parse()getDocument()new XPathParser()new XMLConfigBuilder()parse()parseConfiguration()build(Configuration)
根据时序图可以看得出，创建sessionFactory需要
- 将读入的配置文件流解析为Document对象
- 将Document对象解析为Configuration对象
- 使用Configuration对象，通过build（）方法完成对SqlSessionFactory对象的创建。
1.3 获取数据库操作的会话
Created with Raphaël 2.1.0SqlSessionFactorySqlSessionFactoryDefaultSqlSessionFactoryDefaultSqlSessionFactorySqlSessionSqlSessionopenSession()openSessionFromDataSource()new DefaultSqlSession()
1.4 获取接口实例
Created with Raphaël 2.1.0SqlSessionSqlSessionDefaultSqlSessionDefaultSqlSessionConfigurationConfigurationMapperRegistryMapperRegistryProxyProxyUserMapperUserMappergetMapper()getMapper()getMapper()newInstance()Proxy.newProxyInstance()
Created with Raphaël 2.1.0UserMapperUserMapperMapperProxyMapperProxyMapperMethodMapperMethodDefaultSqlSessionDefaultSqlSessionCachingExecutorCachingExecutorSimpleExecutorSimpleExecutorBaseExecutorBaseExecutorPreparedStatementHandlerPreparedStatementHandlerPreparedStatementPreparedStatementDefaultResultSetHandlerDefaultResultSetHandlergetUserById()execute()selectOne()selectList()query()query()queryFromDatabase()doQuery()prepareStatement()getConnection()prepare()query()execute()handleResultSets()''
在执行具体的 org.apache.ibatis.executor.SimpleExecutor.prepareStatement(StatementHandler, Log)处连接数据库，检查是否能连接成功
数据库连接时序图
Created with Raphaël 2.1.0SimpleExecutorSimpleExecutorBaseExecutorBaseExecutorJdbcTransactionJdbcTransactionDataSourceDataSourceUnpooledDataSourceUnpooledDataSourceDriverManagerDriverManagerDriverInfoDriverInfogetConnection()getConnection()getConnection()openConnection()getConnection()popConnection()new PooledConnection()doGetConnection()getConnection()connect()newInstance()''
