Spring-整合web

spring容器是大家用的同一个容器

1导入jar包

       spring-web.xml

      

2.tomcat启动加载配置文件

      1  servlet --> init(ServletConfig) --> <load-on-startup>

       2 filter --> init(FilterConfig)  --> web.xml注册过滤器自动调用初始化

       3 listener --> ServletContextListener --> servletContext对象监听【】

 

       spring提供*** ContextLoaderListener  --> web.xml  <listener><listener-class>....

              如果只配置***，默认加载xml位置：/WEB-INF/applicationContext.xml

Spring配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  
  <!-- 确定配置文件位置 -->
  <context-param>
  	<param-name>contextConfigLocation</param-name>
  	<param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  
  <!-- 配置spring ***，加载xml配置文件 -->
  <listener>
  	<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <servlet>
    <servlet-name>HelloServlet</servlet-name>
    <servlet-class>com.itheima.web.servlet.HelloServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>HelloServlet</servlet-name>
    <url-pattern>/HelloServlet</url-pattern>
  </servlet-mapping>
</web-app>

从servletContext作用域 获得spring容器 （了解）

public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		// 从application作用域（ServletContext）获得spring容器
		//方式1： 手动从作用域获取
		ApplicationContext applicationContext = 
				(ApplicationContext) this.getServletContext().getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
		//方式2：通过工具获取
		ApplicationContext apppApplicationContext2 = 
				WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
		
		
		//操作
		AccountService accountService =  (AccountService) applicationContext.getBean("accountService");
		accountService.transfer("jack", "rose", 1000);
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		this.doGet(request, response);
	}