如何在Java Web應(yīng)用中獲取Spring的ApplicationContext
作者：leizhimin
ApplicationContext是Spring的容器環(huán)境，通過(guò)ApplicationContext對(duì)象可以訪問(wèn)所有配置的bean。本文中將講述Java Web應(yīng)用中獲取Spring的ApplicationContext。
在Web開(kāi)發(fā)開(kāi)發(fā)中，常常需要從JSP或者Servlet或者Action中獲取ApplicationContext對(duì)象，這時(shí)候，就無(wú)法使用new關(guān)鍵字通過(guò)查找配置文件來(lái)實(shí)例化ApplicationContext這個(gè)對(duì)象了。Spring通過(guò)WebApplicationContextUtils可以方便實(shí)現(xiàn)您的需求。下面看個(gè)例子：
Spring2.5+Struts2環(huán)境下
1. 配置web.xml，通過(guò)這個(gè)配置來(lái)獲取的。
＜?xml version="1.0" encoding="UTF-8"?＞ ＜web-app 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" version="2.5"＞ ?。糲ontext-param＞ ?。紁aram-name＞contextConfigLocation＜/param-name＞ ＜param-value＞/WEB-INF/applicationContext.xml＜/param-value＞ ?。?context-param＞ ?。糵ilter＞ ?。糵ilter-name＞struts2＜/filter-name＞ ?。糵ilter-class＞org.apache.struts2.dispatcher.FilterDispatcher＜/filter-class＞ ?。?filter＞ ＜filter-mapping＞ ?。糵ilter-name＞struts2＜/filter-name＞ ＜url-pattern＞/*＜/url-pattern＞ ?。?filter-mapping＞ ?。糽istener＞ ?。糽istener-class＞org.springframework.web.context.ContextLoaderListener＜/listener-class＞ ?。?listener＞ ?。約ervlet＞ ?。約ervlet-name＞dispatcher＜/servlet-name＞ ?。約ervlet-class＞org.springframework.web.servlet.DispatcherServlet＜/servlet-class＞ ?。糽oad-on-startup＞1＜/load-on-startup＞ ＜/servlet＞ ?。約ervlet-mapping＞ ＜servlet-name＞dispatcher＜/servlet-name＞ ?。紆rl-pattern＞*.form＜/url-pattern＞ ?。?servlet-mapping＞ ＜/web-app＞
2. 在JSP、Servlet、Action中獲取ApplicationContext
＜%@ page import="lavasoft.service.TestService" %＞
＜%@ page import="org.springframework.context.ApplicationContext" %＞
＜%@ page import="org.springframework.web.context.support.WebApplicationContextUtils" %＞
＜%@ page contentType="text/html;charset=UTF-8" language="java" %＞
＜html＞
＜head＞＜title＞Simple jsp page＜/title＞＜/head＞
＜body＞
＜%
// ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(request.getSession().getServletContext());
ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(session.getServletContext());
TestService service = (TestService) ctx.getBean("testService");
String s = service.test();
out.print(s);
%＞
＜/body＞
＜/html＞
＜%@ page import="org.springframework.context.ApplicationContext" %＞
＜%@ page import="org.springframework.web.context.support.WebApplicationContextUtils" %＞
＜%@ page contentType="text/html;charset=UTF-8" language="java" %＞
＜html＞
＜head＞＜title＞Simple jsp page＜/title＞＜/head＞
＜body＞
＜%
// ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(request.getSession().getServletContext());
ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(session.getServletContext());
TestService service = (TestService) ctx.getBean("testService");
String s = service.test();
out.print(s);
%＞
＜/body＞
＜/html＞
Spring+JSP的環(huán)境
在此環(huán)境下web.xml配置會(huì)有些變化：
＜?xml version="1.0" encoding="UTF-8"?＞
＜web-app 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"
version="2.5"＞
?。糲ontext-param＞
?。紁aram-name＞contextConfigLocation＜/param-name＞
?。紁aram-value＞/WEB-INF/applicationContext.xml＜/param-value＞
＜/context-param＞
?。糽istener＞
＜listener-class＞org.springframework.web.context.ContextLoaderListener＜/listener-class＞
?。?listener＞
＜servlet＞
?。約ervlet-name＞dispatcher＜/servlet-name＞
?。約ervlet-class＞org.springframework.web.servlet.DispatcherServlet＜/servlet-class＞
?。糽oad-on-startup＞1＜/load-on-startup＞
?。?servlet＞
?。約ervlet-mapping＞
?。約ervlet-name＞dispatcher＜/servlet-name＞
?。紆rl-pattern＞*.form＜/url-pattern＞
?。?servlet-mapping＞
＜/web-app＞
＜web-app 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"
version="2.5"＞
?。糲ontext-param＞
?。紁aram-name＞contextConfigLocation＜/param-name＞
?。紁aram-value＞/WEB-INF/applicationContext.xml＜/param-value＞
＜/context-param＞
?。糽istener＞
＜listener-class＞org.springframework.web.context.ContextLoaderListener＜/listener-class＞
?。?listener＞
＜servlet＞
?。約ervlet-name＞dispatcher＜/servlet-name＞
?。約ervlet-class＞org.springframework.web.servlet.DispatcherServlet＜/servlet-class＞
?。糽oad-on-startup＞1＜/load-on-startup＞
?。?servlet＞
?。約ervlet-mapping＞
?。約ervlet-name＞dispatcher＜/servlet-name＞
?。紆rl-pattern＞*.form＜/url-pattern＞
?。?servlet-mapping＞
＜/web-app＞
獲取的方式和上述完全一樣。
【編輯推薦】
責(zé)任編輯：楊鵬飛
來(lái)源：
51CTO博客
