SpringBoot杂碎知识 (五) Servlet、Filter、Listenter

在spring boot中添加自己的Servlet有两种方法，代码注册Servlet和注解自动注册：

代码注册

首先贴出 Servlet、Filter、Listenter

package com.maoxs.filter;

import lombok.extern.slf4j.Slf4j;

import javax.servlet.*;
import java.io.IOException;

@Slf4j
public class TestFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("我filter初始化");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("我filter执行");
        filterChain.doFilter(servletRequest, servletResponse);
    }

    @Override
    public void destroy() {
        log.info("我filter销毁");
    }
}

package com.maoxs.listener;

import lombok.extern.slf4j.Slf4j;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

@Slf4j
public class TestListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        log.info("我监听器初始化");
    }

    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {
        log.info("我监听器销毁");
    }
}

package com.maoxs.servlet;

import lombok.extern.slf4j.Slf4j;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


@Slf4j
public class TestServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        log.info("我进入了servlet");
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        log.info("我进入了servlet");
    }

}

然后注入几个bean分别是ServletRegistrationBean、FilterRegistrationBean、ServletListenerRegistrationBean

 @Bean
    public ServletRegistrationBean servletRegistrationBean() {
        return new ServletRegistrationBean(new TestServlet(), "/show/*");// ServletName默认值为首字母小写，即myServlet
    }
    @Bean
    public FilterRegistrationBean indexFilterRegistration() {
        FilterRegistrationBean registration = new FilterRegistrationBean(new TestFilter());
        registration.addUrlPatterns("/");
        return registration;
    }
    @Bean
    public ServletListenerRegistrationBean servletListenerRegistrationBean(){
        ServletListenerRegistrationBean servletListenerRegistrationBean = new ServletListenerRegistrationBean();
        servletListenerRegistrationBean.setListener(new TestListener());
        return servletListenerRegistrationBean;
    }

运行 并访问/show/index 查看日志 

ok 完全生效。

注解自动注册

同样是上面的三个类 ，去除代码注册的bean  然后加入以下注解

然后在启动类上加入注解

运行 并访问/show/index 查看日志 

依然ok

小提示

 在springboot使用springmvc 的时候不需要配置DispatcherServlet的因为已经自动配置了。

但是如果想要加一些初始配置参数如何解决呢，添加以下代码即可。

  @Bean
    public ServletRegistrationBean dispatcherRegistration(DispatcherServlet dispatcherServlet) {
        ServletRegistrationBean registration = new ServletRegistrationBean(dispatcherServlet);
        registration.addUrlMappings("*.do");
        registration.addUrlMappings("*.json");
        return registration;
    }

注：如果不对联系本宝宝及时改正~