Spring Boot学习笔记（二）使用Servlet、Filter、Listener

Servlet

还是得集成HttpServlet，然后重写父类方法。类的上方增加了@WebServlet注解，其实就是代替了xml的配置，可以被spring boot扫描、注册到。

package org.test.Controll;

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="helloServlet",urlPatterns = "/helloServlet")
public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("执行了 Servlet 的 DoGet");
    }
}

Filter

package org.test.Controll;


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

@WebFilter(filterName = "HelloFilter",urlPatterns = "/HelloServlet")
public class HelloFilter 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("执行前doFilter");
        filterChain.doFilter(servletRequest, servletResponse);
        System.out.println("执行后doFilter");
    }

    @Override
    public void destroy() {

    }
}

Listener

package org.test.Controll;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

@WebListener
public class HelloListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        System.out.println("contextInitialized 初始化啦");
    }

    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {

    }
}

注册的两种方式

第一种，使用@ServletComponentScan，自动注册

package org.test;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan; 
@SpringBootApplication
@ServletComponentScan //扫描servlet注解

public class Application {

    public static void main(String[] args) {
        org.springframework.boot.SpringApplication.run(Application.class, args);
    } 
}

第二种，使用@Bean注解自行注册

package org.test;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
@SpringBootApplication  
public class Application {

    public static void main(String[] args) {
        org.springframework.boot.SpringApplication.run(Application.class, args);
    }

    @Bean
    public ServletRegistrationBean getServletRegistrationBean() {
        ServletRegistrationBean bean = new ServletRegistrationBean(new HelloServlet());
        bean.addUrlMappings("/HelloServlet2");
        return bean;
    }
}

Spring Boot学习笔记（二）使用Servlet、Filter、Listener

猜你喜欢