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springBoot整合servlet、Filter、Listener需要在pom中引入如下包：

   
       
    
     org.springframework.boot
        
    
     spring-boot-starter-web
    
   

一、springBoot整合servlet

springBoot使用servlet的API有两种方法

方法1、使用@ServletComponentScan注解

package com.wzy.test;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.web.servlet.ServletComponentScan;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(name = "myServlet",urlPatterns = "/myServlet")//上面这段配置声明该类为servlet程序,等同于在web.xml中配置
   
    映射@ServletComponentScan  //该注解的作用是让springBoot扫描@webServlet等注解@SpringBootApplication  //声明为springBoot应用public class MyFirstServlet extends HttpServlet {    @Override    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        System.out.println("执行了MyFirstServlet的doGet方法......");    }    //启动类    public static void main(String[] args) {        SpringApplication.run(MyFirstServlet.class,args);    }}
   

测试：浏览器中访问http://localhost:8080/myServlet,控制台打印结果如下：

方法2、使用@Bean注解

第1步、写一个HelloServlet类,继承HttpServlet类

package com.wzy.test;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;public class HelloServlet extends HttpServlet {    @Override    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        System.out.println("执行了HelloServlet的doGet方法......");    }}

第2步

package com.wzy.test;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.web.servlet.ServletRegistrationBean;import org.springframework.context.annotation.Bean;@SpringBootApplicationpublic class BeanTest {    public static void main(String[] args) {        SpringApplication.run(BeanTest.class,args);    }    //注册servlet    @Bean    public ServletRegistrationBean getServletRegistrationBean(){        ServletRegistrationBean bean=new ServletRegistrationBean(new HelloServlet());        //设置访问路径        bean.addUrlMappings("/helloServlet");        return bean;    }}

第3步、测试

浏览器输入：http://localhost:8080/helloServlet

控制台打印结果如下：

二、springBoot整合Filter

使用@WebFilter注解

package com.wzy.test;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.web.servlet.ServletComponentScan;import javax.servlet.*;import javax.servlet.annotation.WebFilter;import java.io.IOException;@WebFilter(filterName = "myFilter",urlPatterns = "/myFilter")public class MyFilter implements Filter {    /**     * 初始化     * */    @Override    public void init(FilterConfig filterConfig) throws ServletException {    }    /**     * 执行拦截     * */    @Override    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {        System.out.println("执行了前面代码");        //放行,执行目标资源：/myFilter        filterChain.doFilter(servletRequest,servletResponse);        System.out.println("执行了后面代码");    }    /**     * 销毁     * */    @Override    public void destroy() {    }    public static void main(String[] args) {        SpringApplication.run(MyFilter.class,args);    }}

三、springBoot整合Listener

使用@WebListener注解

package com.wzy.test;import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;import javax.servlet.annotation.WebListener;@WebListenerpublic class MyListener implements ServletContextListener {    @Override    public void contextInitialized(ServletContextEvent sce) {        System.out.println("servletContext对象创建了");    }    @Override    public void contextDestroyed(ServletContextEvent sce) {        System.out.println("servletContext对象被销毁了");    }}

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