//mybatis的配置文件
String resource = "conf.xml";
//使用类加载器加载mybatis的配置文件（它也加载关联的映射文件）
// InputStream is = App.class.getClassLoader().getResourceAsStream(resource);
Reader reader = Resources.getResourceAsReader(resource);
//构建sqlSession的工厂
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
//使用MyBatis提供的Resources类加载mybatis的配置文件（它也加载关联的映射文件）
//Reader reader = Resources.getResourceAsReader(resource);
//构建sqlSession的工厂
//SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
//创建能执行映射文件中sql的sqlSession
SqlSession session = sessionFactory.openSession();
二、认识接口
public interface SqlSessionFactory {
疑问：接口何时实例化??
}
public SqlSessionFactory build(Reader reader) {
return build(reader, null, null);
}
public SqlSessionFactory build(Reader reader, String environment, Properties props) {
return build(new ReaderInputStream(reader), environment, props);
}
public SqlSessionFactory build(InputStream inputStream, String environment, Properties props) {
try {
XMLConfigBuilder parser = new XMLConfigBuilder(inputStream, environment, props);
Configuration config = parser.parse();
return build(config);
} catch (Exception e) {
throw ExceptionFactory.wrapException("Error building SqlSession.", e);
} finally {
ErrorContext.instance().reset();
try {
inputStream.close();
} catch (IOException e) {
// Intentionally ignore. Prefer previous error.
}
}
}
public SqlSessionFactory build(Configuration config) {
//接口此时完成实例化
return new DefaultSqlSessionFactory(config);
}