spring 读取applicationContext方式

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spring 读取applicationContext方式博客分类：?

SpringSpringWebXMLServletBean

加载器目前有两种选择：ContextLoaderListener和ContextLoaderServlet。?
???????? 这两者在功能上完全等同，只是一个是基于Servlet2.3版本中新引入的Listener接口实现，而另一个基于Servlet接口实现。开发中可根据目标Web容器的实际情况进行选择。

配置非常简单，在web.xml中增加：?
<listener>?
?????? <listener-class>?
????????? org.springframework.web.context.ContextLoaderListener
?????? </listener-class>?
</listener>?
或：?
<servlet>?
???????? <servlet-name>context</servlet-name>?
???????? <servlet-class>?
?????????? org.springframework.web.context.ContextLoaderServlet?
???????? </servlet-class>?
???????? <load-on-startup>1</load-on-startup>?
</servlet>

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通过以上配置，Web容器会自动加载/WEB-INF/applicationContext.xml初始化?
ApplicationContext实例，如果需要指定配置文件?位置，可通过context-param加以指定：?
<context-param>?
???????? <param-name>contextConfigLocation</param-name>?
???????? <param-value>/WEB-INF/myApplicationContext.xml</param-value>?
</context-param>?

配置完成之后，即可通过?
WebApplicationContextUtils.getWebApplicationContext方法在Web应用中获取ApplicationContext引用。?

如：ApplicationContext ctx=WebApplicationContextUtils.getWebApplicationContext();?
???????? LoginAction action=(LoginAction)ctx.getBean("action");

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spring为ApplicationContext提供有三种实现（举例）

???????? spring为ApplicationContext提供的3种实现分别为：ClassPathXmlApplicationContext，FileSystemXmlApplicationContext?和XmlWebApplicationContext，其中XmlWebApplicationContext是专为Web工程定制的。使用举例如下：
???1.?FileSystemXmlApplicationContext?
?????????? eg1. ApplicationContext ctx = new?FileSystemXmlApplicationContext?("bean.xml"); //加载单个配置文件?
?????????? eg2.?
?????????????????? String[] locations = {"bean1.xml", "bean2.xml", "bean3.xml"};
?????????????????? ApplicationContext ctx = new?FileSystemXmlApplicationContext?(locations ); //加载多个?配置文件?
?????????? eg3.??????????????? ApplicationContext ctx =new?FileSystemXmlApplicationContext?("D:/project/bean.xml");//根据具体路径加载文件?
??2. ClassPathXmlApplicationContext?
?????????? eg1.??ApplicationContext ctx = new ClassPathXmlApplicationContext("bean.xml");
?????????? eg2.?
?????????????????? String[] locations = {"bean1.xml", "bean2.xml", "bean3.xml"};
?????????????????? ApplicationContext ctx = new ClassPathXmlApplication(locations);
?????????? 注：其中FileSystemXmlApplicationContext?和ClassPathXmlApplicationContext与BeanFactory的xml文件?定位方式一样是基于路径的。
3. XmlWebApplicationContext?
?????? eg1. ServletContext servletContext = request.getSession().getServletContext();????
??????????? ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(servletContext);注 : 一般是 ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());