Mybatis执行流程浅析

从三个主要的对象SqlSessionFactoryBuilder->SqlSessionFactory->SqlSession说起

            inputStream = Resources.getResourceAsStream(resource);

            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

读取全局配置文件

inputStream = Resources.getResourceAsStream(resource);

创建了一个SqlSessionFactoryBuilder对象
调用.getResourceAsStream(resource)方法,完成相关配置并创建SqlSessionFactory对象

//点击进入可知对XML文件进行了解析,从而获得了XMLConfiguration,且该对象继承自Configuration对象.进入下一步的build查看

public SqlSessionFactory build(InputStream inputStream, String environment, Properties properties) {

        SqlSessionFactory var5;

        try {

            XMLConfigBuilder parser = new XMLConfigBuilder(inputStream, environment, properties);

            var5 = this.build(parser.parse());

        } catch (Exception var14) {

            throw ExceptionFactory.wrapException("Error building SqlSession.", var14);

        } finally {

            ErrorContext.instance().reset();

            try {

                inputStream.close();

            } catch (IOException var13) {

            }

        }

        return var5;

    }

//加Configuration对象加载给SqlSessionFactory对象,完成了SqlSessionFactory的创建

    public SqlSessionFactory build(Configuration config) {

        return new DefaultSqlSessionFactory(config);

    }

调用SqlSessionFactory对象的openSession方法完SqlSession对象的实例化

//往下:可以看出是先继承了Configuration中的Environment,完成了transaction相关的操作,继而产生executor,最后才完成了SqlSession的实例化,能力有限,这里就不深究了

private SqlSession openSessionFromDataSource(ExecutorType execType, TransactionIsolationLevel level, boolean autoCommit) {

        Transaction tx = null;

        DefaultSqlSession var8;

        try {

            Environment environment = this.configuration.getEnvironment();

            TransactionFactory transactionFactory = this.getTransactionFactoryFromEnvironment(environment);

            tx = transactionFactory.newTransaction(environment.getDataSource(), level, autoCommit);

            Executor executor = this.configuration.newExecutor(tx, execType);

            var8 = new DefaultSqlSession(this.configuration, executor, autoCommit);

        } catch (Exception var12) {

            this.closeTransaction(tx);

            throw ExceptionFactory.wrapException("Error opening session.  Cause: " + var12, var12);

        } finally {

            ErrorContext.instance().reset();

        }

        return var8;

    }

CURD的执行(产生错误就回滚)
检测是否执行(产生错误就回滚)
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Mybatis执行流程浅析

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