SpringBoot2.X注册Servlet三大组件(Servlet、Filter、Listener)

一、自定义三大组件

1.1、自定义Servlet

package com.atguigu.springboot.servlet;

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

/**
 * 自定义servlet
 */
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       resp.getWriter().write("Hello MyServlet");
    }
}

1.2、自定义Filter

package com.atguigu.springboot.filter;

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

/**
 * 自定义filter
 */
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

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

    @Override
    public void destroy() {

    }
}

1.3、自定义Listener

package com.atguigu.springboot.listener;


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

/**
 * 自定义listener
 */
public class MyListener implements ServletContextListener{
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("contextInitialized...web应用启动");
    }

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

二、将组件注册到SpringBoot容器

package com.atguigu.springboot.config;

import com.atguigu.springboot.filter.MyFilter;
import com.atguigu.springboot.listener.MyListener;
import com.atguigu.springboot.servlet.MyServlet;
import org.springframework.boot.web.server.ConfigurableWebServerFactory;
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
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 javax.servlet.Filter;
import java.util.Arrays;

@Configuration
public class MyServerConfig {

    //注册三大组件
    /**
     * 将自定义的servlet注册到springboot容器中
     * @return
     */
    @Bean
    public ServletRegistrationBean servletRegistrationBean(){
        ServletRegistrationBean<MyServlet> registrationBean = new ServletRegistrationBean<>(new MyServlet(),"/myServlet");
        registrationBean.setLoadOnStartup(1);
        return registrationBean;
    }

    /**
     * 把自定义的filter注册到容器中
     * @return
     */
    @Bean
    public FilterRegistrationBean filterRegistrationBean(){
        FilterRegistrationBean<Filter> registrationBean = new FilterRegistrationBean<>();
        registrationBean.setFilter(new MyFilter());
        registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));
        return registrationBean;
    }

    /**
     * 把自定义的listener注册到容器中
     * @return
     */
    @Bean
    public ServletListenerRegistrationBean myListener(){
        ServletListenerRegistrationBean<MyListener> registrationBean = new ServletListenerRegistrationBean<>(new MyListener());
        return registrationBean;
    }

    //配置嵌入式的Servlet容器
    @Bean
    public WebServerFactoryCustomizer<ConfigurableWebServerFactory> webServerFactoryWebServerFactoryCustomizer(){
        return new WebServerFactoryCustomizer<ConfigurableWebServerFactory>() {
            //定制嵌入式的Servlet容器相关的规则
            @Override
            public void customize(ConfigurableWebServerFactory factory) {
                factory.setPort(8083);
            }
        };
    }
}