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ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");HelloService helloService = (HelloService) applicationContext.getBean("helloService");helloService.sayHello();问题: 每次请求都会加载Spring环境,初始化所有Bean ,性能问题 !!!
解决方案一: 将代码放入Servlet init 中 , 无法保证所有Servlet都能使用 ApplicationContext
解决方案二: ServletContext,在tomcat启动时, 加载Spring配置文件,获得对象 ,放入ServletContext
* ServletContextListener
保存 ContextLoaderListener 完成在Servlet初始化阶段,加载Spring配置文件,将工厂对象放入 ServletContext
<listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener>配置全局参数 contextConfigLocation 指定 配置文件位置
<context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value></context-param>从ServletContext中获得 Spring工厂
第一种:
WebApplicationContext applicationContext = (WebApplicationContext) getServletContext().getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);第二种:
WebApplicationContext applicationContext = WebApplicationContextUtils.getWebApplicationContext(getServletContext());publicclassHelloService{publicvoid sayHello(){System.out.println("hello,Spring web");}}<?xml version="1.0" encoding="UTF-8"?><beansxmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"><beanid="helloService"class="cn.itcast.service.HelloService"></bean></beans><?xml version="1.0" encoding="UTF-8"?><web-appversion="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"><!-- 配置Spring 监听器 --><listener><listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener><!-- 配置Spring配置文件所在位置 --><context-param><param-name>contextConfigLocation</param-name><param-value>classpath:applicationContext.xml</param-value></context-param><display-name></display-name><servlet><servlet-name>HelloServlet</servlet-name><servlet-class>cn.itcast.servlet.HelloServlet</servlet-class></servlet><servlet-mapping><servlet-name>HelloServlet</servlet-name><url-pattern>/hello</url-pattern></servlet-mapping><welcome-file-list><welcome-file>index.jsp</welcome-file></welcome-file-list></web-app>publicclassHelloServletextendsHttpServlet{publicvoid doGet(HttpServletRequest request,HttpServletResponse response)throwsServletException,IOException{WebApplicationContext applicationContext =WebApplicationContextUtils.getWebApplicationContext(getServletContext());HelloService helloService =(HelloService) applicationContext.getBean("helloService"); helloService.sayHello();}publicvoid doPost(HttpServletRequest request,HttpServletResponse response)throwsServletException,IOException{ doGet(request, response);}}1、 导入spring-test.jar
2、 编写测试用例
@RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration(locations = "classpath:applicationContext.xml") // 指定配置文件位置public class HelloServiceTest { @Autowired private HelloService helloService; // 注入需要测试对象 @Test // 测试 public void demo2() { helloService.sayHello(); // 调用测试方法 }}
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原文地址:http://www.cnblogs.com/tangwan/p/4674976.html