Servlet技术6_通过继承HttpServlet去实现Servlet程序

一般在实际项目开发中，都是使用继承HttpServlet类的形式去实现Servlet程序

步骤：

1. 编写一个类去继承HttpServlet类
2. 根据业务需要重写doGet或doPost方法
3. 到web.xml中的配置Servlet程序的访问地址

HelloServlet2:

package com.servlet1;

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 HelloServlet2 extends HttpServlet {
    
    
    /**
     * doGet()在get请求的时候调用
     */
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
        System.out.println("HelloServlet2的doGet方法");
    }

    /**
     * doPost()在post请求的时候调用
     */
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
        System.out.println("HelloServlet2的doPost方法");
    }
}

web.xml配置文件添加:

<servlet>
	<servlet-name>HelloServlet2</servlet-name>
	<servlet-class>com.servlet1.HelloServlet2</servlet-class>
</servlet>
<servlet-mapping>
	<servlet-name>HelloServlet2</servlet-name>
	<url-pattern>/hello2</url-pattern>
</servlet-mapping>