?Web三大組件的注冊

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Servlet

@WebServlet(“/user.action”)

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<servlet>

</servlet>

<servlet-mapping>

</servlet-mapping>

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Filter

@WebFilter()

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<filter>

</filter>

<filter-mapping>

</filter-mapping>

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Listener

@WebListener

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<listener>

<listener-class></listener-class>

</listener>

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UserServlet.java

package com.sxt.controller;import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException;public class UserServlet extends HttpServlet {@Overridepublic void init(ServletConfig config) throws ServletException {String env = config.getInitParameter("env");String hello = config.getInitParameter("hello");System.out.println(env+" "+hello);}@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {this.doPost(req,resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {System.out.println("hello--UserServlet");} } /*** 創建UserServlet*/@Bean("userServlet")@ConditionalOnClass(value = {UserServlet.class})public UserServlet userServlet(){return new UserServlet();}/*** 注冊UserServlet*/@Bean@ConditionalOnBean(value = {UserServlet.class})public ServletRegistrationBean<UserServlet> servletRegistrationBeanUserServlet(UserServlet userServlet){ // public ServletRegistrationBean<UserServlet> servletRegistrationBeanUserServlet(){ // UserServlet userServlet=new UserServlet();//創建注冊器對象ServletRegistrationBean<UserServlet> registrationBean=new ServletRegistrationBean<>();//注入ServletregistrationBean.setServlet(userServlet);//設置參數registrationBean.addInitParameter("env","UTF-8");registrationBean.addInitParameter("hello","你好");//設置映射registrationBean.addUrlMappings("/user1.action","/user2.action");return registrationBean;}

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AppFilter.java

package com.sxt.controller;import javax.servlet.*; import java.io.IOException;public class AppFilter implements Filter {@Overridepublic void init(FilterConfig filterConfig) throws ServletException {String env = filterConfig.getInitParameter("env");String hello = filterConfig.getInitParameter("hello");System.out.println(env+" "+hello);}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {System.out.println("doFilter");chain.doFilter(request,response);}@Overridepublic void destroy() {} } /*** 創建Filter*/@Bean("appFilter")@ConditionalOnClass(value = {AppFilter.class})public AppFilter appFilter(){return new AppFilter();}/*** 注冊Filter*/@Bean@ConditionalOnBean(value = {AppFilter.class})public FilterRegistrationBean<AppFilter> filterFilterRegistrationBeanAppFilter(AppFilter appFilter){//創建注冊器FilterRegistrationBean<AppFilter> registrationBean=new FilterRegistrationBean<>();//注入filterregistrationBean.setFilter(appFilter);//設置參數registrationBean.addInitParameter("env","filter-UTF-8");registrationBean.addInitParameter("hello","filter-你好");//設置映射 // registrationBean.addUrlPatterns("/*");registrationBean.addServletNames("userServlet");return registrationBean;}

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Listener的分類

監聽三大作用域

ServletContext

|--ServletContextListener ????ServletContextAttributeListener

HttpSession

|--HttpSessionListner ????HttpSessionAttributeListener

ServletRequest

|--ServletReqeustListener ??ServletRequestAttributeListener

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AppListener.java

package com.sxt.controller;import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener;public class AppListener implements ServletContextListener {@Overridepublic void contextInitialized(ServletContextEvent sce) {System.out.println("contextInitialized");}@Overridepublic void contextDestroyed(ServletContextEvent sce) {} } package com.sxt.config;import com.sxt.controller.AppListener; import lombok.Data; import org.springframework.boot.autoconfigure.condition.ConditionalOnBean; import org.springframework.boot.autoconfigure.condition.ConditionalOnClass; import org.springframework.boot.context.properties.ConfigurationProperties; import org.springframework.boot.web.servlet.ServletListenerRegistrationBean; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.stereotype.Component;@Configuration @Component @ConfigurationProperties(prefix = "web") @Data public class WebConfig {private Boolean applistenerEnable=true;/*** 創建Listener*/@Bean@ConditionalOnClass(value = {AppListener.class})public AppListener appListener(){return new AppListener();}@Bean@ConditionalOnBean(value = {AppListener.class})public ServletListenerRegistrationBean<AppListener> servletListenerRegistrationBeanAppListener(AppListener listener){//創建注冊器ServletListenerRegistrationBean<AppListener> bean=new ServletListenerRegistrationBean<AppListener>();//注入listenerbean.setListener(listener);bean.setEnabled(applistenerEnable);return bean;} }

總結

以上是生活随笔為你收集整理的Web三大组件的注册——Servlet、Filter、Listener(监听三大作用域： ServletContext、HttpSession、ServletRequest )的全部內容，希望文章能夠幫你解決所遇到的問題。

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