• 013-Spring Boot web【二】静态资源、Servlet、Filter、listenter


    一、静态资源

    1.1、webapp默认支持静态资源

    在src/main/webapp下建立user.html默认支持访问

    1.2、默认内置静态资源目录。可被直接访问

    查看包:spring-boot-autoconfigure-1.5.9.RELEASE.jar下的:org.springframework.boot.autoconfigure.web;

    查看:ResourceProperties,其中

        private static final String[] CLASSPATH_RESOURCE_LOCATIONS = {
                "classpath:/META-INF/resources/", "classpath:/resources/",
                "classpath:/static/", "classpath:/public/" };

    默认放在以上四个目录均可被访问。

    可以通过修改配置项,在src/main/resources下的application.properties中

    spring.resources.staticLocations=classpath:/html/

    二、spring boot中使用Servlet【原始】以来Servlet3.x注解功能

    2.1、使用Servlet

    新建一个UserServlet.java

    package com.lhx.spring.springboot_web_ext;
    
    import java.io.IOException;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    @WebServlet("/user.do")
    public class UserServlet extends HttpServlet {
    
        private static final long serialVersionUID = 1L;
    
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            resp.getWriter().print("user servlet");
        }
    }
    View Code

    并且在启动类上增加Servlet扫描注解:ServletComponentScan

    @ServletComponentScan
    @SpringBootApplication
    public class App {
        public static void main(String[] args) {
            ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
            //context.close();
        }
    }
    View Code

    访问即可

    2.2、使用Filter

    新建一个LogFilter.java拦截User.do

    package com.lhx.spring.springboot_web_ext;
    
    import java.io.IOException;
    
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.annotation.WebFilter;
    
    @WebFilter("/user.do")
    public class LogFilter implements Filter {
    
        @Override
        public void destroy() {
            // TODO Auto-generated method stub
    
        }
    
        @Override
        public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
                throws IOException, ServletException {
            System.out.println("income log filter " + arg0.getRemoteHost());
            arg2.doFilter(arg0, arg1);
        }
    
        @Override
        public void init(FilterConfig arg0) throws ServletException {
            // TODO Auto-generated method stub
    
        }
    
    }
    View Code

    此时运行即可

    2.3、使用Listener

    package com.lhx.spring.springboot_web_ext;
    
    import java.time.LocalDate;
    
    import javax.servlet.ServletContextEvent;
    import javax.servlet.ServletContextListener;
    import javax.servlet.annotation.WebListener;
    
    @WebListener
    public class MyContextListener implements ServletContextListener {
    
        @Override
        public void contextDestroyed(ServletContextEvent arg0) {
            // TODO Auto-generated method stub
    
        }
    
        @Override
        public void contextInitialized(ServletContextEvent arg0) {
            System.out.println("app startup at " + LocalDate.now().toString());
    
        }
    
    }
    View Code

    此时运行即可

    三、spring boot中使用Servlet【Configuration配置】不依赖Servlet3.0,使用Servlet2.x可以使用

    3.1、使用Servlet

    增加BookServlet.java,注意没有注解

    package com.lhx.spring.springboot_web_ext.servlet;
    
    import java.io.IOException;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class BookServlet extends HttpServlet {
    
        private static final long serialVersionUID = 1L;
    
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            System.out.println("test");
        }
    }
    View Code

    增加配置类,ServletConfiguration.java

    package com.lhx.spring.springboot_web_ext.servlet;
    
    import org.springframework.boot.SpringBootConfiguration;
    import org.springframework.boot.web.servlet.ServletRegistrationBean;
    import org.springframework.context.annotation.Bean;
    
    @SpringBootConfiguration
    public class ServletCongfiguration {
    
        @Bean
        public ServletRegistrationBean createBookServlet() {
            ServletRegistrationBean servlet = new ServletRegistrationBean(new BookServlet(),"book.do");
            return servlet;
        }
    
    }
    View Code

    此时访问即可。

    3.2、使用Filter

    增加EchoFilter.java

    package com.lhx.spring.springboot_web_ext.servlet;
    
    import java.io.IOException;
    
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.http.HttpServletRequest;
    
    public class EchoFilter implements Filter {
    
        @Override
        public void destroy() {
            // TODO Auto-generated method stub
    
        }
    
        @Override
        public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
                throws IOException, ServletException {
            HttpServletRequest req = (HttpServletRequest) arg0;
            System.out.println("test" + req.getRequestURI());
            arg2.doFilter(arg0, arg1);
    
        }
    
        @Override
        public void init(FilterConfig arg0) throws ServletException {
            // TODO Auto-generated method stub
    
        }
    
    }
    View Code

    在配置类,ServletConfiguration.java增加

        @Bean
        public FilterRegistrationBean createFilterRegistrationBean() {
            FilterRegistrationBean filter = new FilterRegistrationBean();
            filter.setFilter(new EchoFilter());
            filter.setUrlPatterns(Arrays.asList("/book.do"));
            return filter;
        }
    View Code

    3.3、使用Listner

    增加StartupListener .java

    package com.lhx.spring.springboot_web_ext.servlet;
    
    import javax.servlet.ServletContextEvent;
    import javax.servlet.ServletContextListener;
    
    public class StartupListener implements ServletContextListener {
    
        @Override
        public void contextDestroyed(ServletContextEvent arg0) {
            // TODO Auto-generated method stub
    
        }
    
        @Override
        public void contextInitialized(ServletContextEvent arg0) {
            System.out.println("=================");
        }
    
    }
    View Code

    在配置类,ServletConfiguration.java增加

        @Bean
        public ServletListenerRegistrationBean<StartupListener> createServletListenerRegistrationBean() {
            ServletListenerRegistrationBean<StartupListener> registrationBean = new ServletListenerRegistrationBean<StartupListener>(new StartupListener());
            return registrationBean;
        }
    View Code

    注:一般使用2中注解,因为Spring boot基于spring 4.x ,spring 4.x 开发的web一般使用Servlet3.x以上

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  • 原文地址:https://www.cnblogs.com/bjlhx/p/8407097.html
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