【Spring Boot】031-整合 Servlet 、Filter 和 Listener

訾博ZiBo

发布于 2025-01-06 15:43:12

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【Spring Boot】031-整合 Servlet 、Filter 和 Listener

一、概述

一般情况下，使用 Spring 、Spring MVC 这些框架之后，基本上就告别了 Servlet 、 Filter 以及 Listenter 了，但是有时在整合一些第三方框架时需要使用到这些。Spring Boot 对于整合这些基本的 Web 组件也提供了很好的支持。

二、代码演示

1、Servlet

package com.zibo.api.web;

import lombok.extern.slf4j.Slf4j;

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

@WebServlet(urlPatterns = "/hi")
@Slf4j
public class MyServlet extends HttpServlet {

    @Override
    public void init() throws ServletException {
        log.warn("MyServlet => 初始化成功");
        super.init();
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        log.warn("MyServlet => doGet");
        super.doGet(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        log.warn("MyServlet => doPost");
        super.doPost(req, resp);
    }
}

2、Filter

package com.zibo.api.web;

import lombok.extern.slf4j.Slf4j;

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

@WebFilter("/*")
@Slf4j
public class MyFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.warn("MyFilter ==> init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.warn("MyFilter ==> doFilter");
    }

    @Override
    public void destroy() {
        log.warn("MyFilter ==> destroy");
    }
}

3、Listener

package com.zibo.api.web;

import lombok.extern.slf4j.Slf4j;

import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.annotation.WebListener;

@WebListener
@Slf4j
public class MyListener implements ServletRequestListener {
    @Override
    public void requestDestroyed(ServletRequestEvent sre) {
        log.warn("MyListener ==> requestDestroyed");
    }

    @Override
    public void requestInitialized(ServletRequestEvent sre) {
        log.warn("MyListener ==> requestInitialized");
    }
}

4、启动类

package com.zibo.api;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@SpringBootApplication
@ServletComponentScan // 加上此注解以使得上面三个被扫描到
public class ApiApplication {
    
    public static void main(String[] args) {
        SpringApplication.run(ApiApplication.class, args);
    }

}