SpringBoot注册Servlet Filter Listener三大组件

转自：https://www.jianshu.com/p/6830989985e9

1.注册Servlet

配置类：

@Configuration
public class MyServerConfig {
    // 注册三大组件
    @Bean
    public ServletRegistrationBean myServlet(){
        ServletRegistrationBean servletregistrationbean =  new ServletRegistrationBean(new MyServlet() ,"/myservlet"){
        };
        return servletregistrationbean;
    }
    // 配置嵌入式Servlet容器
    @Bean
    public WebServerFactoryCustomizer<ConfigurableWebServerFactory> myembeddedServletContainerCustomizer(){
        return new WebServerFactoryCustomizer<ConfigurableWebServerFactory>(){
            // 定制嵌入式Servlet容器相关规则
            @Override
            public void customize(ConfigurableWebServerFactory factory) {
                factory.setPort(8081);
            }
        };
    }
}

自定义的Servlet类

public class MyServlet extends HttpServlet {
    /**
     * 处理get请求
     * @param req
     * @param resp
     * @throws ServletException
     * @throws IOException
     */
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }
    /**
     * 处理post请求
     * @param req
     * @param resp
     * @throws ServletException
     * @throws IOException
     */
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("hello");
    }
}

然后在浏览器访问http://localhost:8081/myservlet

 

image.png

2.注册Filter

    // 注册filter
    @Bean
    public FilterRegistrationBean myfilter(){
        FilterRegistrationBean filterregistrationbean = new FilterRegistrationBean();
        filterregistrationbean.setFilter(new MyFilter());
        filterregistrationbean.setUrlPatterns(Arrays.asList("/hello","/myservlet"));
        return filterregistrationbean;
    }

public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void destroy() {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("myfilter");
        filterChain.doFilter(servletRequest,servletResponse);
    }

然后访问"/myservlet"或者"/hello"控制台都会打印myfilter

 

image.png

3.注册Listener(这里以ServletContextListener为例)

    // 注册Listener
    @Bean
    public ServletListenerRegistrationBean mylistener(){
        ServletListenerRegistrationBean servletListener = new ServletListenerRegistrationBean<MyListener>(new MyListener());
        return servletListener;
    }

public class MyListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("web项目生成");
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("web项目销毁");
    }
}

然后启动项目

 

image.pn

作者：二营长家的张大炮
链接：https://www.jianshu.com/p/6830989985e9
来源：简书
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