Servlet的层次结构

Servlet–>GenericServlet–>HttpServlet

HTTP请求有很多种类型，常用的有四种

GET 读取

POST 保存

PUT 修改

DELETE 删除

GenerServlet实现Servlet接口，同时为他的子类屏蔽了不常用的方法，子类只需要重写Service方法即可。

HttpServlet继承GenerServlet,根据请求类型进行分发处理,GET进入doGet方法，POST进入doPost方法

开发者自定义的Servlet类只需要继承HttpServlet即可，重写doGet和doPost

package com.southwind.servlet;

import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/hellos")
public class HelloServlet implements  MyHttpServlet {
    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException{
        response.getWriter().write("helloget");
    }
    @Override
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws  IOException{
        response.getWriter().write("hellopost");
    }
}

MyHttpServlet文件

package com.southwind.servlet;

import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
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("/hello")
public class MyHttpServlet extends MyGenericServlet {
    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        HttpServletRequest request =(HttpServletRequest) servletRequest;
        HttpServletResponse response=(HttpServletResponse) servletResponse;
        //获取请求类型
        String method=request.getMethod();
        switch (method){
            case "Get":
                this.doGet(request,response);
                break;
            case:"POST":
                this.doPost(request,response);
                break;
        }

    }
    public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException{

    }
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException{

    }

}

MyGenericServlet文件

package com.southwind.servlet;

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

public class MyGenericServlet 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 {

    }

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

    @Override
    public void destroy() {

    }
}

来源：CSDN

作者：小庄hua

链接：https://blog.csdn.net/qq_41370549/article/details/104504549

标签

servlet

response