Jsp 中如何获取spring的bean呢？
方式一：通过上下文
Html代码
- <?xml version="1.0" encoding="UTF-8" ?>
- <%@ page language="java" contentType="text/html; charset=UTF-8"
- pageEncoding="UTF-8"%>
- <%@page import="org.springframework.web.context.support.WebApplicationContextUtils"%>
- <%@page import="org.springframework.context.ApplicationContext"%>
- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
- <html xmlns="http://www.w3.org/1999/xhtml">
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
- <title>Insert title here</title>
- </head>
- <body>
- <%
- ServletContext context = request.getSession().getServletContext();
- ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(context);
- Object <span style="font-size: 1em; line-height: 1.5;">supermarketDao</span><span style="font-size: 1em; line-height: 1.5;">= ctx.getBean("supermarketDao");</span>
- System.out.println("jsp:"+<span style="font-size: 1em; line-height: 1.5;">supermarketDao</span><span style="font-size: 1em; line-height: 1.5;">);</span>
- %>
- </body>
- </html>
问题：JSP页面中获取的bean与spring 容器中的bean是同一个吗？
是的。
方式二：通过类路径加载bean文件,得到bean工厂
Html代码
- <?xml version="1.0" encoding="UTF-8" ?>
- <%@page import="org.springframework.beans.factory.BeanFactory"%>
- <%@page import="org.springframework.context.support.ClassPathXmlApplicationContext"%>
- <%@ page language="java" contentType="text/html; charset=UTF-8"
- pageEncoding="UTF-8"%>
- <%@page import="org.springframework.web.context.support.WebApplicationContextUtils"%>
- <%@page import="org.springframework.context.ApplicationContext"%>
- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
- <html xmlns="http://www.w3.org/1999/xhtml">
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
- <title>Insert title here</title>
- </head>
- <body>
- <%
- ClassPathXmlApplicationContext appContext = new ClassPathXmlApplicationContext("beans.xml","user_beans.xml","goods_beans.xml","supermarket_beans.xml","aop.xml","upload_beans.xml");
- BeanFactory factory = (BeanFactory) appContext;
- Object obj=factory.getBean("supermarketDao");
- System.out.println("jsp2:"+obj);
- %>
- </body>
- </html>
问题：JSP页面中获取的bean与spring 容器中的bean是同一个吗？
不是的。
总结：（1）通过WebApplicationContextUtils 获取bean是直接从spring容器中拿的；
（2）通过ClassPathXmlApplicationContext，实际上又解析了一遍xml，即又创建了一个新的spring容器，所有获取的bean与web上下文中是不同的。
