java SpringBoot（十）Web原生组件注入（Servlet、Filter、Listener）

妖狐艹你老母 2022-10-15 13:56 124阅读 0赞

1、Servlet

import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    //Web源生组件注入 
    @WebServlet(urlPatterns = "/my")
    public class MyServlet extends HttpServlet {
    
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            resp.getWriter().write("66666");
        }
    }

2、Filter

import lombok.extern.slf4j.Slf4j;
    
    import javax.servlet.*;
    import javax.servlet.annotation.WebFilter;
    import java.io.IOException;
    
    @Slf4j
    @WebFilter(urlPatterns={"/css/*","/images/*"}) //my
    public class MyFilter implements Filter {
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
            log.info("MyFilter初始化完成");
        }
    
        @Override
        public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
            log.info("MyFilter工作");
            chain.doFilter(request,response);
        }
    
        @Override
        public void destroy() {
            log.info("MyFilter销毁");
        }
    }

3、Listener

import lombok.extern.slf4j.Slf4j;
    
    import javax.servlet.ServletContextEvent;
    import javax.servlet.ServletContextListener;
    import javax.servlet.annotation.WebListener;
    
    
    
    @Slf4j
    //@WebListener
    public class MySwervletContextListener implements ServletContextListener {
    
    
        @Override
        public void contextInitialized(ServletContextEvent sce) {
            log.info("MySwervletContextListener监听到项目初始化完成");
        }
    
        @Override
        public void contextDestroyed(ServletContextEvent sce) {
            log.info("MySwervletContextListener监听到项目销毁");
        }
    }

**Bean方式注入**

import org.springframework.boot.web.servlet.FilterRegistrationBean;
    import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
    import org.springframework.boot.web.servlet.ServletRegistrationBean;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import java.util.Arrays;
    
    /**
     * 1、MyServlet --> /my
     * 2、DispatcherServlet --> /
     */
    // (proxyBeanMethods = true)：保证依赖的组件始终是单实例的
    @Configuration(proxyBeanMethods = true)
    public class MyRegistConfig {
    
        @Bean
        public ServletRegistrationBean myServlet(){
            MyServlet myServlet = new MyServlet();
    
            return new ServletRegistrationBean(myServlet,"/my","/my02");
        }
    
    
        @Bean
        public FilterRegistrationBean myFilter(){
    
            MyFilter myFilter = new MyFilter();
    //        return new FilterRegistrationBean(myFilter,myServlet());
            FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(myFilter);
            filterRegistrationBean.setUrlPatterns(Arrays.asList("/my","/css/*"));
            return filterRegistrationBean;
        }
    
        @Bean
        public ServletListenerRegistrationBean myListener(){
            MySwervletContextListener mySwervletContextListener = new MySwervletContextListener();
            return new ServletListenerRegistrationBean(mySwervletContextListener);
        }
    }