springboot(4)添加Servlet、Listener、Filter

怼烎@ 2022-06-01 06:21 244阅读 0赞

## 1、添加注解支持 ##

以下方式1中的方法，均需要向springboot的入口类添加注解@ServletComponentScan。添加该注解以后，以下注解才会生效：@WebServlet 、@WebListener、@WebFilter

package com.wxtx;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.web.servlet.ServletComponentScan;
    
    @ServletComponentScan
    @SpringBootApplication
    public class TXSpringBootApplication { 
        public static void main(String[] args) {
            SpringApplication.run(TXSpringBootApplication.class, args);
        }
    }

## 2、Servlet ##

#### 方式1： ####

@WebServlet(name="testServlet",urlPatterns="/testServlet")
    public class TestServlet extends HttpServlet { 
    
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            resp.getWriter().write("hello world");
        }
    }

#### 方式2： ####

@Bean
    public ServletRegistrationBean servletRegistrationBean(){
        ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
        servletRegistrationBean.addUrlMappings("/demo");
        servletRegistrationBean.setServlet(new DemoServlet2());
        return servletRegistrationBean;
    }

## 3、Listener ##

#### 方式1： ####

@WebListener
    public class TestListener implements ServletContextListener { 
    
        @Override
        public void contextInitialized(ServletContextEvent sce) {
            System.out.println("contextInitialized");
        }
    
        @Override
        public void contextDestroyed(ServletContextEvent sce) {
        }
    
    }

#### 方式2： ####

@Bean
    public ServletListenerRegistrationBean servletListenerRegistrationBean(){
        ServletListenerRegistrationBean servletListenerRegistrationBean =  new ServletListenerRegistrationBean();
        servletListenerRegistrationBean.setListener(new Log4jConfigListener());
        servletListenerRegistrationBean.addInitParameter("log4jConfigLocation","classpath:log4j.properties");
        return servletListenerRegistrationBean;
    }

## 4、Filter ##

#### 方式1： ####

@WebFilter(urlPatterns="/*")
    public class TestFilter implements Filter { 
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
        }
    
        @Override
        public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain)
                throws IOException, ServletException {
            HttpServletRequest request = (HttpServletRequest) req;
            System.out.println(request.getRemoteAddr());
            chain.doFilter(req, resp);
        }
    
        @Override
        public void destroy() {
        }
    }

#### 方式2： ####

@Bean
    public FilterRegistrationBean filterRegistrationBean(){
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(new OpenSessionInViewFilter());
        Set<String> set = new HashSet<String>();
        set.add("/");
        filterRegistrationBean.setUrlPatterns(set);
        return filterRegistrationBean;
    }