那比如没有腾讯VIP能爬取到VIP视频内容吗？这个算黑客技术还是爬虫？

springboot2.4做验证的时候。添加了验证没有生效。，据说2.3以后没有了，但是加上两坐标好像还不行，

一：老师我这是xml文件呀，为什么还是错误呀！

老师，我的用户登录与退出功能都是正常的，获取用户登录信息显示的是500

报错信息：

2021-03-25 18:46:17.772 ERROR 8528 --- [nio-8080-exec-4] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

我代码和老师是一样的。

获取菜单信息也是显示500

获取用户信息和获取菜单信息的报错是一样的。

用float类型时，后面必须加f/F嘛？、、、、、

老师，这个错误是怎么回事？我之前把一个写过的包名改了，然后再写别的就出现这种情况

是改了包名，没自动注入吗？

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'tbItemParamController': Unsatisfied dependency expressed through field 'tbItemParamService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'tbItemParamServiceImpl': Injection of @Reference dependencies is failed; nested exception is java.lang.IllegalStateException: Failed to check the status of the service com.ego.dubbo.service.TbItemParamDubboService. No provider available for the service com.ego.dubbo.service.TbItemParamDubboService from the url zookeeper://192.168.8.128:2181/org.apache.dubbo.registry.RegistryService?application=ego-manage&dubbo=2.0.2&init=false&interface=com.ego.dubbo.service.TbItemParamDubboService&methods=selectCount,selectByPage&pid=7588&qos.enable=false&register.ip=192.168.1.101&release=2.7.5&side=consumer&sticky=false&timestamp=1616666460363 to the consumer 192.168.1.101 use dubbo version 2.7.5

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:643) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:130) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]

at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]

at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]

at com.ego.ManageApplication.main(ManageApplication.java:10) [classes/:na]

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'tbItemParamServiceImpl': Injection of @Reference dependencies is failed; nested exception is java.lang.IllegalStateException: Failed to check the status of the service com.ego.dubbo.service.TbItemParamDubboService. No provider available for the service com.ego.dubbo.service.TbItemParamDubboService from the url zookeeper://192.168.8.128:2181/org.apache.dubbo.registry.RegistryService?application=ego-manage&dubbo=2.0.2&init=false&interface=com.ego.dubbo.service.TbItemParamDubboService&methods=selectCount,selectByPage&pid=7588&qos.enable=false&register.ip=192.168.1.101&release=2.7.5&side=consumer&sticky=false&timestamp=1616666460363 to the consumer 192.168.1.101 use dubbo version 2.7.5

at com.alibaba.spring.beans.factory.annotation.AbstractAnnotationBeanPostProcessor.postProcessPropertyValues(AbstractAnnotationBeanPostProcessor.java:145) ~[spring-context-support-1.0.5.jar:na]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1427) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1287) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

... 19 common frames omitted

Caused by: java.lang.IllegalStateException: Failed to check the status of the service com.ego.dubbo.service.TbItemParamDubboService. No provider available for the service com.ego.dubbo.service.TbItemParamDubboService from the url zookeeper://192.168.8.128:2181/org.apache.dubbo.registry.RegistryService?application=ego-manage&dubbo=2.0.2&init=false&interface=com.ego.dubbo.service.TbItemParamDubboService&methods=selectCount,selectByPage&pid=7588&qos.enable=false&register.ip=192.168.1.101&release=2.7.5&side=consumer&sticky=false&timestamp=1616666460363 to the consumer 192.168.1.101 use dubbo version 2.7.5

at org.apache.dubbo.config.ReferenceConfig.createProxy(ReferenceConfig.java:355) ~[dubbo-2.7.5.jar:2.7.5]

at org.apache.dubbo.config.ReferenceConfig.init(ReferenceConfig.java:266) ~[dubbo-2.7.5.jar:2.7.5]

at org.apache.dubbo.config.ReferenceConfig.get(ReferenceConfig.java:151) ~[dubbo-2.7.5.jar:2.7.5]

at org.apache.dubbo.config.spring.beans.factory.annotation.ReferenceAnnotationBeanPostProcessor.getOrCreateProxy(ReferenceAnnotationBeanPostProcessor.java:249) ~[dubbo-2.7.5.jar:2.7.5]

at org.apache.dubbo.config.spring.beans.factory.annotation.ReferenceAnnotationBeanPostProcessor.doGetInjectedBean(ReferenceAnnotationBeanPostProcessor.java:142) ~[dubbo-2.7.5.jar:2.7.5]

at com.alibaba.spring.beans.factory.annotation.AbstractAnnotationBeanPostProcessor.getInjectedObject(AbstractAnnotationBeanPostProcessor.java:358) ~[spring-context-support-1.0.5.jar:na]

at com.alibaba.spring.beans.factory.annotation.AbstractAnnotationBeanPostProcessor$AnnotatedFieldElement.inject(AbstractAnnotationBeanPostProcessor.java:538) ~[spring-context-support-1.0.5.jar:na]

at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:130) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]

at com.alibaba.spring.beans.factory.annotation.AbstractAnnotationBeanPostProcessor.postProcessPropertyValues(AbstractAnnotationBeanPostProcessor.java:141) ~[spring-context-support-1.0.5.jar:na]

... 30 common frames omitted

>>> import io

>>> a = "happy day"

>>> aio = io.StringIO(a)

>>> aio

<_io.StringIO object at 0x0000018C7D427AF0>

>>> aio.getvalue()

'happy day'

>>> sio.seek(8)

Traceback (most recent call last):

  File "<pyshell#5>", line 1, in <module>

    sio.seek(8)

NameError: name 'sio' is not defined

>>> aio.seek(8)

8

>>> aio.write("y")

1

>>> aio.getvalue()

'happy day'

>>> aio.write("a")

1

>>> aio.getvalue()

'happy daya'

>>> 

老师 这是咋了

type和object是什么？两者之间有什么关系？

我的理解是type是创建str、tuple、list、dict、int、set这些类的元类，object不知道是什么？看源码type是继承object类的

老师，4个字节是32位，那为什么可以表示成2的32次方呢？

发现原因了,之前使用IDEA一键修改变量名的时候将ContentType中的Text一并修改了,所以将html当成文件下载了。

文件上传成功了,可以在文件夹里找到文件,但是不显示上传成功信息,反而弹出下载fileUpload.do文件,这是什么原因啊?

package com.example.ServletDemo.part;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
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;

@WebServlet(name = "FileUploadServlet", value = "/fileUpload.do") @MultipartConfig public class FileUploadServlet
    extends HttpServlet {
    @Override protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
        this.doPost(request, response);

    }

    @Override protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

        response.setContentType("describe/html;charset=utf-8");
        String describe = request.getParameter("describe");
        Part uploadFile = request.getPart("uploadFile");// 要与<input>中的name一致

        // 获取文件上传的字节流
        // InputStream inputStream = uploadFile.getInputStream();
        // 给文件改名
        String fileName = UUID.randomUUID().toString() + uploadFile.getSubmittedFileName()
            .substring(uploadFile.getSubmittedFileName().lastIndexOf("."));
        // 路径转换
        ServletContext servletContext = this.getServletContext();
        String realPath = servletContext.getRealPath("image/" + fileName);
        // 直接调用Part对象的write方法,不用手动创建字节流
        uploadFile.write(realPath);
        PrintWriter out = response.getWriter();
        out.println("<html><body>");
        out.println("上传成功!" + describe);
        out.println("</body></html>");
        out.flush();
        out.close();
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="fileUpload.do" method="post" enctype="multipart/form-data">
    文件描述:<input type="text" name="describe"/>
    上传文件:<input type="file" name="uploadFile"/><br/>
    <input type="submit" value="submit"/>
</form>
</body>
</html>

老师，等于号前后一定要有空格吗，我看高老师敲出来的都有空格

这个空格可以通过设置哪里自动就是等于号前后有空格嘛，还是只能通过手敲空格

下面这个是我敲出来的

老师，为啥我的Xshell连接不上Linux？

语句块是什么意思啊，后期会讲嘛？、、、、、、

老师，作用域是什么意思啊，，，，，，，，，，，，，，，，