请问，老师上课做的笔记在哪里可以获取（凑够20个字）

老师，您好，我一直有一个疑问。就是说什么时候使用super,又或者什么时候使用我们的普通继承。两者我一直不知道如果在不同的场景使用

请问一下，虽然可以不用纠结ide，但是如果企业规定使用某个ide怎么办呢？比如我熟悉pycharm，但是企业用的是eclipse呢？

请问一下既然Python3不兼容Python2，从Python3学起，那么如果出现了Python4，我们需要从头学起吗？

请问一下既然Python3不兼容Python2，从Python3学起，那么如果出现了Python

请问老师：

from multiprocessing import Process,Pool
from time import sleep

def f1(name):
    print(f'开始执行{name}')
    sleep(2)
    print(f'{name}执行结束')


if __name__ == '__main__':
    with Pool(3) as pool:
        pool.map(f1,('进程1','进程2','进程3','进程4','进程5'))

    sleep(5)
    print('主进程执行结束')

用with 语句，上面可以执行，为何下面执行不了

from multiprocessing import Process,Pool
from time import sleep

def f1(name):
    print(f'开始执行{name}')
    sleep(2)
    print(f'{name}执行结束')


if __name__ == '__main__':
    with Pool(3) as pool:
        pool.apply_async(func=f1,args=('进程1',))
        pool.apply_async(func=f1, args=('进程2',))
        pool.apply_async(func=f1, args=('进程3',))
        pool.apply_async(func=f1, args=('进程4',))
        pool.apply_async(func=f1, args=('进程5',))
        pool.apply_async(func=f1, args=('进程6',))
        pool.apply_async(func=f1, args=('进程7',))

    sleep(5)
    print('主进程执行结束')

老师，这节课的两个进程一个是开始执行就有的进程，还有一个是Process产生的进程么？

这是啥意思？为什么会报这个错？？？？？？？？？？？？？？？？？？？？？

在点击门诊挂号时页面提示数据校验异常提示

控制台报这样的错误

后台代码也没报错

这种情况该怎么解决？

老师,为啥会报错.,我看视频教程没有报错呀

这个hashset是链表加数组，对于算法结果相同的会在数组处加入链表，那么是不是这个hashset数组长度永远都是16啊

内存底层的分析是何含义，自己分析代码感觉会很难，也就是说给一个要求，让做出功能，如何分析去做？

使用xml文件配置网页报500错误是咋回事，老师能帮忙看看嘛

<?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"
         metadata-complete="false">
    <context-param>
        <param-name>key1</param-name>
        <param-value>BJSXT</param-value>
    </context-param>
    <context-param>
        <param-name>key2</param-name>
        <param-value>BJSXT</param-value>
    </context-param>
    <servlet>
        <servlet-name>demoServlet</servlet-name>
        <servlet-class>com.example.demo.DemoServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>demoServlet</servlet-name>
        <url-pattern>/demo.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>getRequestDataServlet</servlet-name>
        <servlet-class>com.example.demo.GetRequestDataServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>getRequestDataServlet</servlet-name>
        <url-pattern>/getinfo.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>getRequestHeaderServlet</servlet-name>
        <servlet-class>com.example.demo.GetRequestHeaderServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>getRequestHeaderServlet</servlet-name>
        <url-pattern>/getHeader.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>LanguageServlet</servlet-name>
        <servlet-class>com.example.demo.LanguageServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LanguageServlet</servlet-name>
        <url-pattern>/Languages.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>RespByteServlet</servlet-name>
        <servlet-class>com.example.demo.RespByteServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>RespByteServlet</servlet-name>
        <url-pattern>/RespByte.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>RedirectServlet</servlet-name>
        <servlet-class>com.example.demo.RedirectServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>RedirectServlet</servlet-name>
        <url-pattern>/Redirect.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>DownFileServlet</servlet-name>
        <servlet-class>com.example.demo.DownFileServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>DownFileServlet</servlet-name>
        <url-pattern>/Down.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>GetBaseInfoServlet</servlet-name>
        <servlet-class>com.example.demo.GetBaseInfoServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>GetBaseInfoServlet</servlet-name>
        <url-pattern>/getBaseInfo.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>ContextReadInfoServlet</servlet-name>
        <servlet-class>com.example.demo.ContextReadInfoServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ContextReadInfoServlet</servlet-name>
        <url-pattern>/Context.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>GlobalContainerServlet</servlet-name>
        <servlet-class>com.example.demo.GlobalContainerServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>GlobalContainerServlet</servlet-name>
        <url-pattern>/Global.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>GetConfigInfoServlet</servlet-name>
        <servlet-class>com.example.demo.GetConfigInfoServlet</servlet-class>
        <init-param>
            <param-name>key1</param-name>
            <param-value>BJSXT</param-value>
        </init-param>
        <init-param>
            <param-name>key2</param-name>
            <param-value>ITBZ</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>GetConfigInfoServlet</servlet-name>
        <url-pattern>/Config.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>CreatCookieSrvlet</servlet-name>
        <servlet-class>com.example.demo.CreatCookieSrvlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>CreatCookieSrvlet</servlet-name>
        <url-pattern>/Cookie.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>GetCookieDataServlet</servlet-name>
        <servlet-class>com.example.demo.GetCookieDataServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>GetCookieDataServlet</servlet-name>
        <url-pattern>/GetCookie.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>WelcomeServlet</servlet-name>
        <servlet-class>com.example.demo.WelcomeServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>WelcomeServlet</servlet-name>
        <url-pattern>/Welcome.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>CreateHttpSessionServlet</servlet-name>
        <servlet-class>com.example.demo.CreateHttpSessionServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>CreateHttpSessionServlet</servlet-name>
        <url-pattern>/CreatSession.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>GetHttpSessionDataServlet</servlet-name>
        <servlet-class>com.example.demo.GetHttpSessionDataServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>GetHttpSessionDataServlet</servlet-name>
        <url-pattern>/GetSessionData.do</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>1</session-timeout>
    </session-config>
    <servlet>
        <servlet-name>WelcomeSessionServlet</servlet-name>
        <servlet-class>com.example.demo.WelcomeSessionServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>WelcomeSessionServlet</servlet-name>
        <url-pattern>/WelcomeSession.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>AutoStartServlet</servlet-name>
        <servlet-class>com.example.demo.AutoStartServlet</servlet-class>
        <init-param>
            <param-name>path</param-name>
            <param-value>image</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>AutoStartServlet</servlet-name>
        <url-pattern>/auto.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>ThreadSafeServlet</servlet-name>
        <servlet-class>com.example.demo.ThreadSafeServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ThreadSafeServlet</servlet-name>
        <url-pattern>/Safe.do</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>FileUploadServlet</servlet-name>
        <servlet-class>com.example.demo.FileUploadServlet</servlet-class>
        <multipart-config>
            <file-size-threshold>2000</file-size-threshold>
        </multipart-config>
    </servlet>
    <servlet-mapping>
        <servlet-name>FileUploadServlet</servlet-name>
        <url-pattern>/fileupload.do</url-pattern>
    </servlet-mapping>
</web-app>

package com.example.demo;

import javax.servlet.ServletContext;
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 javax.servlet.http.Part;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.UUID;

public class FileUploadServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        String desc = req.getParameter("desc");
        Part part=req.getPart("file");
//        InputStream inputStream = part.getInputStream();
        String filename= UUID.randomUUID().toString()+part.getSubmittedFileName().substring(part.getSubmittedFileName().lastIndexOf("."));
        ServletContext servletContext = this.getServletContext();
        String realPath = servletContext.getRealPath("image"+filename);
        part.write(realPath);
        PrintWriter out=resp.getWriter();
        out .println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
        out.println("<HTML>");
        out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println(" <BODY>");
        out.println("上传成功");
        out.println("</BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }
}

//对对象进行反序列化
public static void test2(){
    ObjectInputStream ois = null;
    try{
        ois = new ObjectInputStream(new
                FileInputStream("E:/object.txt"));
        Person p =(Person)ois.readObject();
        System.out.println(p);
    }catch(Exception e){
        e.printStackTrace();
    }finally{
        try{
            if(ois != null){
                ois.close();
            }
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}
java.io.InvalidClassException: cn.bzsxt.bytestream.User; local class incompatible: stream classdesc serialVersionUID = 1732458846381710476, local class serialVersionUID = -6028733942570062611
    at java.base/java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:689)
    at java.base/java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1898)
    at java.base/java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1764)
    at java.base/java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2055)
    at java.base/java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1586)
    at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:423)
    at cn.bzsxt.Test.Test.test2(Test.java:40)
    at cn.bzsxt.Test.Test.main(Test.java:11)

老师查了好久说不是代码问题 测了好几遍都报错

public class Person implements Serializable {
    private String name;
    private int age;

    public Person() {
    }

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

老师，这里返回的为什么是这样的，而不是返回一个对象地址