一.需求

Web 开发使用 Controller 基本上可以完成大部分需求，但是我们还可能会用到 Servlet、 FilterListene

二、案例

　　2.1　　通过注册 ServletRegistrationBean、 FilterRegistrationBean 和ServletListenerRegistrationBean 获得

package com.shyroke;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
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 util.MyFilter;
import util.MyListener;
import util.MyServlet;

@SpringBootApplication
public class Springboot01Application {

@Bean
public ServletRegistrationBean servletRegistrationBean() {
return new ServletRegistrationBean(new MyServlet(), "/servlet");
}

@Bean
public FilterRegistrationBean filterRegistrationBean() {
return new FilterRegistrationBean(new MyFilter(), servletRegistrationBean());
}

@Bean
public ServletListenerRegistrationBean<MyListener> listenerRegistrationBean(){
return new ServletListenerRegistrationBean<MyListener>(new MyListener());
}

public static void main(String[] args) {
SpringApplication.run(Springboot01Application.class, args);
}
}

　　2.2　　MyServlet.java

package util;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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 {
System.out.println("我是servlet");

resp.getWriter().write("hello world servlet");
}

}

　　2.3　　MyFilter.java

package util;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class MyFilter implements Filter {

@Override
public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
System.out.println("我是filter");
chain.doFilter(request, response);
}

@Override
public void destroy() {
// TODO Auto-generated method stub

}

}

　　2.4　　MyListener.java

package util;

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

public class MyListener implements ServletContextListener{

@Override
public void contextInitialized(ServletContextEvent sce) {
System.out.println("contextInitialized");

}

@Override
public void contextDestroyed(ServletContextEvent sce) {
System.out.println("contextDestroyed");

}

}

　　2.5　　结果

说明servlet生效

filter和listener生效