Servlet

第一种继承HttpServlet

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
//自定义类继承HttpServlet
public class DemoServlet extends HttpServlet {
    //重写doGet和doPost方法
    //doGet处理get请求
    //doPost处理post请求
    //在doPost方法中调用doGet方法，不管是get请求还是post请求都交给doGet方法处理
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("成功");
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req,resp);
    }
}

第二种：继承GenercServlet

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

public class Demo02Servlet extends GenericServlet {

    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        System.out.println("操作成功");
    }
}

第三种：实现Servlet

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

public class Demo03Servlet implements Servlet {
    @Override
    public void init(ServletConfig servletConfig) throws ServletException {

    }

    @Override
    public ServletConfig getServletConfig() {
        return null;
    }

    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        System.out.println("奥力给");
    }

    @Override
    public String getServletInfo() {
        return null;
    }

    @Override
    public void destroy() {

    }
}

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">
    <!--配置Servlet-->
    <!--声明Servlet-->
    <servlet>
        <!--servlet的名称-->
        <servlet-name>DemoServlet</servlet-name>
        <!--servlet的全类名-->
        <servlet-class>com.qf.servlet.DemoServlet</servlet-class>

    </servlet>
    <!--给Servlet设置访问名称
        Servlet should have a mapping
        -->
    <servlet-mapping>
        <!--servlet的名称-->
        <servlet-name>DemoServlet</servlet-name>
        <!--servlet访问名称-->
        <url-pattern>/demo</url-pattern>
    </servlet-mapping>


    <!--继承GenericServlet-->
    <servlet>
        <!--servlet的名称-->
        <servlet-name>Demo02Servlet</servlet-name>
        <!--servlet的全类名-->
        <servlet-class>com.qf.servlet.Demo02Servlet</servlet-class>

    </servlet>
    <!--给Servlet设置访问名称
        Servlet should have a mapping
        -->
    <servlet-mapping>
        <!--servlet的名称-->
        <servlet-name>Demo02Servlet</servlet-name>
        <!--servlet访问名称-->
        <url-pattern>/demo02</url-pattern>
    </servlet-mapping>


    <!--实现Servlet-->
    <servlet>
        <!--servlet的名称-->
        <servlet-name>Demo03Servlet</servlet-name>
        <!--servlet的全类名-->
        <servlet-class>com.qf.servlet.Demo03Servlet</servlet-class>

    </servlet>
    <!--给Servlet设置访问名称
        Servlet should have a mapping
        -->
    <servlet-mapping>
        <!--servlet的名称-->
        <servlet-name>Demo03Servlet</servlet-name>
        <!--servlet访问名称-->
        <url-pattern>/demo03</url-pattern>
    </servlet-mapping>


</web-app>