Mybatis_Spring_SpringMVC的启动方式.md

Mybatis_Spring_SpringMVC的启动方式

一、Mybatis启动方式（读取配置文件）

//加载mybatis-config.xml到输入流
InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
//通过输入流构建SqlSessionFactory对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//通过SqlSessionFactory对象得到一个SqlSession对象，每个数据库操作都依靠SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();
//通过SqlSession对象得到一个mapper的实现对象
UserMapper mapper = sqlSession.getMapper(UserMapper.class);

public UserTest() throws IOException {
}

二、Spring启动方式（读取配置文件）

//1.创建ioc容器对象：
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
//2.从容器中获得维护的Student实例

//通过id
Student student1 = (Student)applicationContext.getBean("student");
//通过类名
Student student2 = applicationContext.getBean(Student.class);

三、SpringMVC启动方式（和web结合，启动tomcat去启动SpringMVC）

• 在web.xml编写DispatcherServlet

   <?xml version="1.0" encoding="UTF-8"?>
   <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
   	 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   	 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
   	 http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
   	 version="3.1">
       <!-- 配置DispatcherServlet -->
       <!-- The front controller of this Spring Web application,  -->
   		<!-- responsible for handling all application requests -->
       <servlet>
   	<servlet-name>DispatcherServlet</servlet-name>
   	<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
   	<init-param>
   	    <param-name>contextConfigLocation</param-name>
   	    <param-value>classpath:springmvc.xml</param-value>
   	</init-param>
   	<load-on-startup>1</load-on-startup>
       </servlet>
  
       <!-- Map all requests to the DispatcherServlet for handling -->
       <servlet-mapping>
   	<servlet-name>DispatcherServlet</servlet-name>
   	<url-pattern>/</url-pattern>
       </servlet-mapping>
  
   </web-app>