一个servelt处理请求过程

访问路径:
http://locahost:8080/secondServlet/date

Servlet

package org.bingo.servlet;

import javax.servlet.GenericServlet;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import java.io.IOException;
import java.util.Date;

public class SecondServlet extends GenericServlet {

    /**
     * Servlet处理请求过程
     * 1. 客户端浏览器发起请求, http://locahost:8080/secondServlet/date
     * 2. Connector监听端口接收请求, 把请求报文封装成Request和Response对象, 交给Engine处理
     * 3. Engine找到对应虚拟主机localhost
     * 4. 虚拟主机交给对应Context处理
     *      项目启动时, 回去以下目录查找应用, 并为其在容器中创建一个Context对象
     *      1)webapps
     *      2)server.xml Host节点下的Contenxt
     *      3)conf/Catalina/localhost下的xml文件
     * 5. web.xml中, Context匹配访问路径/date, 把Request和Response对象交给SecondServlet
     * 6. Servlet从Request对象中获取请求参书并处理, 通过Response对象依次返回给客户端浏览器
     * @param servletRequest
     * @param servletResponse
     * @throws ServletException
     * @throws IOException
     */
    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        System.out.println(new Date());
        servletResponse.getWriter().println(new Date());
    }

}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>second</servlet-name>
        <servlet-class>org.bingo.servlet.SecondServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>second</servlet-name>
        <url-pattern>/date</url-pattern>
    </servlet-mapping>

</web-app>