有效沟通问答-【官方】百战程序员_IT在线教育培训机构

在创建多线程 ServerThread类里面run（）方法里try catch里User user=(User) ois.readObject();（24行）报异常 ClassNotFoundException，视频在21：05处左右有；跟着敲得不知道为什么，出来这个异常，如何把ClassNotFoundException异常用try catch 处理了还是抛出，下面关闭流socket.close();会报错如何是好？和视频不一样

JAVA 全系列/第二阶段：JAVA 基础深化和提高/网络编程（旧） 3889楼

没有什么错误，但是网页就是打不开

JAVA 全系列/第十一阶段：消息中间件与高并发处理/RabbitMQ（旧） 3890楼

没事了，老师，width这些不是自己打的

JAVA 全系列/第一阶段：JAVA 快速入门/IDEA的使用和第一个java项目 3891楼

老师，我这个是？

PS D:\vscodeproject2\爬虫\Scarpy\scarpy05> & D:/python_env/spider2_env_/Scripts/Activate.ps1

(spider2_env_) PS D:\vscodeproject2\爬虫\Scarpy\scarpy05> & D:/python_env/spider2_env_/Scripts/python.exe d:/vscodeproject2/爬虫/Scarpy/scarpy05/scarpy05/begin.py

2023-12-26 22:01:30 [scrapy.utils.log] INFO: Scrapy 2.6.1 started (bot: scarpy05)

2023-12-26 22:01:30 [scrapy.utils.log] INFO: Versions: lxml 4.8.0.0, libxml2 2.9.12, cssselect 1.1.0, parsel 1.6.0, w3lib 1.22.0, Twisted 22.4.0, Python 3.10.0 (tags/v3.10.0:b494f59, Oct 4 2021, 19:00:18) [MSC v.1929 64 bit (AMD64)], pyOpenSSL 22.0.0 (OpenSSL 1.1.1n 15 Mar 2022), cryptography 36.0.2, Platform Windows-10-10.0.19045-SP0

2023-12-26 22:01:30 [scrapy.crawler] INFO: Overridden settings:

{'BOT_NAME': 'scarpy05',

'NEWSPIDER_MODULE': 'scarpy05.spiders',

'SPIDER_MODULES': ['scarpy05.spiders']}

2023-12-26 22:01:30 [scrapy.utils.log] DEBUG: Using reactor: twisted.internet.selectreactor.SelectReactor

2023-12-26 22:01:30 [scrapy.extensions.telnet] INFO: Telnet Password: 2e9c559873783f27

2023-12-26 22:01:30 [scrapy.middleware] INFO: Enabled extensions:

['scrapy.extensions.corestats.CoreStats',

'scrapy.extensions.telnet.TelnetConsole',

'scrapy.extensions.logstats.LogStats']

2023-12-26 22:01:30 [scrapy.middleware] INFO: Enabled downloader middlewares:

['scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',

'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',

'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',

'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',

'scrapy.downloadermiddlewares.retry.RetryMiddleware',

'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',

'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',

'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',

'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',

'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware',

'scrapy.downloadermiddlewares.stats.DownloaderStats']

2023-12-26 22:01:30 [scrapy.middleware] INFO: Enabled spider middlewares:

['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',

'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',

'scrapy.spidermiddlewares.referer.RefererMiddleware',

'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',

'scrapy.spidermiddlewares.depth.DepthMiddleware']

Unhandled error in Deferred:

2023-12-26 22:01:30 [twisted] CRITICAL: Unhandled error in Deferred:

Traceback (most recent call last):

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\crawler.py", line 206, in crawl

return self._crawl(crawler, *args, **kwargs)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\crawler.py", line 210, in _crawl

d = crawler.crawl(*args, **kwargs)

File "D:\python_env\spider2_env_\lib\site-packages\twisted\internet\defer.py", line 1905, in unwindGenerator

return _cancellableInlineCallbacks(gen)

File "D:\python_env\spider2_env_\lib\site-packages\twisted\internet\defer.py", line 1815, in _cancellableInlineCallbacks

_inlineCallbacks(None, gen, status)

--- <exception caught here> ---

File "D:\python_env\spider2_env_\lib\site-packages\twisted\internet\defer.py", line 1660, in _inlineCallbacks

result = current_context.run(gen.send, result)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\crawler.py", line 102, in crawl

self.engine = self._create_engine()

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\crawler.py", line 116, in _create_engine

return ExecutionEngine(self, lambda _: self.stop())

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\core\engine.py", line 84, in __init__

self.scraper = Scraper(crawler)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\core\scraper.py", line 75, in __init__

self.itemproc = itemproc_cls.from_crawler(crawler)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\middleware.py", line 59, in from_crawler

return cls.from_settings(crawler.settings, crawler)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\middleware.py", line 41, in from_settings

mw = create_instance(mwcls, settings, crawler)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\utils\misc.py", line 166, in create_instance

instance = objcls.from_crawler(crawler, *args, **kwargs)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\media.py", line 76, in from_crawler

pipe = cls.from_settings(crawler.settings)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\images.py", line 112, in from_settings

return cls(store_uri, settings=settings)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\images.py", line 55, in __init__

super().__init__(store_uri, settings=settings, download_func=download_func)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\files.py", line 329, in __init__

self.store = self._get_store(store_uri)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\files.py", line 378, in _get_store

store_cls = self.STORE_SCHEMES[scheme]

builtins.KeyError: 'd'

2023-12-26 22:01:30 [twisted] CRITICAL:

Traceback (most recent call last):

File "D:\python_env\spider2_env_\lib\site-packages\twisted\internet\defer.py", line 1660, in _inlineCallbacks

result = current_context.run(gen.send, result)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\crawler.py", line 102, in crawl

self.engine = self._create_engine()

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\crawler.py", line 116, in _create_engine

return ExecutionEngine(self, lambda _: self.stop())

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\core\engine.py", line 84, in __init__

self.scraper = Scraper(crawler)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\core\scraper.py", line 75, in __init__

self.itemproc = itemproc_cls.from_crawler(crawler)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\middleware.py", line 59, in from_crawler

return cls.from_settings(crawler.settings, crawler)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\middleware.py", line 41, in from_settings

mw = create_instance(mwcls, settings, crawler)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\utils\misc.py", line 166, in create_instance

instance = objcls.from_crawler(crawler, *args, **kwargs)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\media.py", line 76, in from_crawler

pipe = cls.from_settings(crawler.settings)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\images.py", line 112, in from_settings

return cls(store_uri, settings=settings)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\images.py", line 55, in __init__

super().__init__(store_uri, settings=settings, download_func=download_func)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\files.py", line 329, in __init__

self.store = self._get_store(store_uri)

File "D:\python_env\spider2_env_\lib\site-packages\scrapy\pipelines\files.py", line 378, in _get_store

store_cls = self.STORE_SCHEMES[scheme]

KeyError: 'd'

(spider2_env_) PS D:\vscodeproject2\爬虫\Scarpy\scarpy05>

Python 全系列/第十五阶段：Python 爬虫开发/scrapy框架使用 3892楼

PlaneGame0.8.zip

老师，请问为什么我运行的时候会报这样的错误，我的是JDK1.8，在没有用数组生成50个炮弹之前也会出现类似的错误，但是我把双缓冲的代码写到main方法之后就好了，又报这样的错误是什么原因？而且第45行代码并没有报错

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException

at cn.sxt.game.MyGameFrame.paint(MyGameFrame.java:45)

at sun.awt.RepaintArea.paintComponent(Unknown Source)

at sun.awt.RepaintArea.paint(Unknown Source)

at sun.awt.windows.WComponentPeer.handleEvent(Unknown Source)

at java.awt.Component.dispatchEventImpl(Unknown Source)

at java.awt.Container.dispatchEventImpl(Unknown Source)

at java.awt.Window.dispatchEventImpl(Unknown Source)

at java.awt.Component.dispatchEvent(Unknown Source)

at java.awt.EventQueue.dispatchEventImpl(Unknown Source)

at java.awt.EventQueue.access$500(Unknown Source)

at java.awt.EventQueue$3.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)

at java.awt.EventQueue$4.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)

at java.awt.EventQueue.dispatchEvent(Unknown Source)

at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)

at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)

at java.awt.EventDispatchThread.pumpEvents(Unknown Source)

at java.awt.EventDispatchThread.run(Unknown Source)

JAVA 全系列/第一阶段：JAVA 快速入门/飞机大战小项目训练 3893楼

SLB系列

老师我想知道ctrl+z是撤销，那与之对应的恢复是那个

Python 全系列/第一阶段：Python入门/Python入门（动画版） 3894楼

请问为什么在pycharm上运行结果四个id都不一样而在cmd上运行结果正确（即id(a)=id(c),id(b)=id(d)）

Python 全系列/第四阶段：函数式编程和核心特性/内存管理 3895楼

已经解决了，是我自己太粗心了

多删除了一个标签

JAVA 全系列/（旧的隐藏）第七阶段：JAVA 高级技术/MyCat 3896楼

老师我的也没飞机哪里出错了啊

飞机大战.zip

JAVA 全系列/第一阶段：JAVA 快速入门/飞机大战小项目训练 3897楼

l老师比如有三个条件查询时，能用and and and这样吗

Python 全系列/第五阶段：数据库编程/mysql的使用 3898楼

package DOM方式;

import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;

import org.w3c.dom.NamedNodeMap;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

public class TesTDDMParse {

public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {

//(1) 创建一个DocumentBuilderFactory的对象

DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();

//(2)创建DocumenyBuilder对象

DocumentBuilder db=dbf.newDocumentBuilder();

//(3)通过DocumentBuilder的parse（. . .）方法得到Document对象

Document doc=db.parse("book.xml");

//(4)通过getElementsByTagName（. . .）方法获取到节点的列表

NodeList bookList=doc.getElementsByTagName("book");

System.out.println(bookList.getLength());

//(5)通过for循环遍历，每一个节点

for(int i=0; i<bookList.getLength();i++) {

//(6)得到每一个节点的属性和属性值

Node book=bookList.item(i);

NamedNodeMap attrs=book.getAttributes(); //得到属性的集合

//遍历每一个属性

for(int j=0;j<attrs.getLength();j++){

//得到每一个属性

Node id=attrs.item(j);

System.out.println("属性的名称"+id.getNodeName()+"\t"+id.getNodeValue());

}

System.out.println("\n每个节点的名称和节点的值");

//(7)得到每个节点名和节点值

for(int i=0;i<bookList.getLength();i++){

//得到每一个book节点

Node book=bookList.item(i);

NodeList subNode=book.getChildNodes();

//使用for循环遍历每一个book的子节点

for(int j=0;j<subNode.getLength();j++) {

Node childNode=subNode.item(j);

//System.out.println(childNode.getNodeName());

short type=childNode.getNodeType();//获取节点的类型

if(type==childNode.getNodeType()) {

System.out.println("节点的名称:"+childNode.getNodeName()+"\t"+childNode.getTextContent());

}

这是books

<?xml version="1.0" encoding="UTF-8"?>

<books>

<name>Java开发</name>

</book>

</book>

</books>

这是错误

Exception in thread "main" java.io.FileNotFoundException: D:\java\第二阶段\XML技术\books.xml (系统找不到指定的文件。)

at java.base/java.io.FileInputStream.open0(Native Method)

at java.base/java.io.FileInputStream.open(FileInputStream.java:213)

at java.base/java.io.FileInputStream.<init>(FileInputStream.java:155)

at java.base/java.io.FileInputStream.<init>(FileInputStream.java:110)

at java.base/sun.net.www.protocol.file.FileURLConnection.connect(FileURLConnection.java:86)

at java.base/sun.net.www.protocol.file.FileURLConnection.getInputStream(FileURLConnection.java:184)

at java.xml/com.sun.org.apache.xerces.internal.impl.XMLEntityManager.setupCurrentEntity(XMLEntityManager.java:654)

at java.xml/com.sun.org.apache.xerces.internal.impl.XMLVersionDetector.determineDocVersion(XMLVersionDetector.java:150)

at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:860)

at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:824)

at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)

at java.xml/com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:246)

at java.xml/com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:339)

at java.xml/javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:178)

at DOM方式.TesTDDMParse.main(TesTDDMParse.java:25)

JAVA 全系列/第二阶段：JAVA 基础深化和提高/XML 技术（旧） 3899楼

老师，我增加了验证码和个人介绍的验证，但是即使我输入正确也会提示错误信息，我找了很久都没有找到，帮我看看是什么问题，谢谢

63表单验证2-正则表达式-有问题吗.zip

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>	
		<script type="text/javascript">
			/**********验证码生成***********/
			function YZM(){			
				//生成4位随机整数
				var ran=Math.floor(Math.random()*9000+1000)			
				//获得span对象
				var span=document.getElementById('yzm_span')			
				span.innerText =ran;			
			}		
			/******************校验用户名*********/
			function checkName(){
			//汉字的正则表达式	符号是//			
				var reg=/^[\u4e00-\u9fa5]{3,5}$/		
				//调用check方法
				check('uname',reg)			
			}
			/******************校验密码*********/		
			function checkPwd(){				
				//数字的正则表达式
				var reg=/^\d{3,6}$/			
				check('pwd',reg)			
			}	
			/******************手机号码的验证*********/		
			function checkPhone(){				
				//手机号码的正则表达式
				var reg=/^(13[0-9]|14[5|7]|15[0|1|2|3|5|6|7|8|9]|18[0|1|2|3|5|6|7|8|9])\d{8}$/			
				check('phone',reg)			
			}	
			/******************邮箱的验证*********/		
			function checkEmail(){				
				//邮箱的正则表达式
				var reg=/^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/			
				check('email',reg)			
			}	
			/*******************提取公共部分************/
			function check(id,reg){				
				//获取密码
				var uname=document.getElementById(id);		
				var val=uname.value			
				//获得alt属性
				var alt=uname.alt ;				
				//获得span对象
				var span=document.getElementById(id+'_span')			
				//密码的正则表达式			
				//var reg=/^\d{3,6}$/			
				if (val==null||val==''){					
					span.innerText='×'+alt+'不能为空'				
					span.style.color='red';				
				}else if(reg.test(val)){				
					span.innerText='√'+alt+'合法 '				
					span.style.color='green';				
				}else{				
					span.innerText='×'+alt+'不合法 '				
					span.style.color='red';
				}			
			}
			/**********验证码的验证***************/
			function checkYZM(){
				//获取输入的值
				var yzm=document.getElementsByName("yzm");
				//获取输入的验证码的值做判断
				var yzm2=yzm.value	
				//获取span对象
				var span=document.getElementById("yzm_span2")
				if (yzm2==null||yzm2==''||yzm2!=ran){
					span.innerHTML="验证码错误";  
					span.style.color="red";
					return false;
				}else{
					span.innerHTML="验证码正确";
					span.style.color="green";
					return true;
				}
			}			
			/**********性别的验证***************/
			function checkSex(){
				var sex=document.getElementsByName("sex");
				var span=document.getElementById("sex_span")
				for(var i in sex){
					if(sex[i].checked){
						span.innerHTML="性别选择成功";
						span.style.color="green";
						return true;
					}
				}
				span.innerHTML="请选择性别";
				span.style.color="red";
				return false;
				
			}
			/**********爱好的验证***************/
			function checkHobby(){
				var hobby=document.getElementsByName("hobby");
				var span=document.getElementById("hobby_span")
				for(var i in hobby){
					if(hobby[i].checked){
						span.innerHTML="爱好选择成功";
						span.style.color="green";
						return true;
					}
				}
				span.innerHTML="请选择你的爱好";
				span.style.color="red";
				return false;
				
			}
			/**********个人介绍验证***************/
			function checkIntroduce(){
				//获取输入的值
				var introduce=document.getElementsByName("introduce");
				//获取输入的个人介绍的值做判断
				var introduce2=introduce.value	
				//获取span对象
				var span=document.getElementById("introduce_span")
				if (introduce2==null||introduce2==''){
					span.innerHTML="请输入个人介绍";  
					span.style.color="red";
					return false;
				}else{
					span.innerHTML="个人介绍输入正确";
					span.style.color="green";
					return true;
				}
			}

			/*
			 * 正则表达式
			 * 对数据格式进行一定的规范限制
			 * ^：开始
			 * [0-9 A-Z a-z]:所有数字 字母
			 * {2,4}:限制位数，段域，至少2位，最多4位
			 * {3}:指定三位数
			 * {2,}:代表2到正无穷位置
			 * *代表随意位置
			 * $：代表限制结尾
			 * \d：代表[0-9]
			 * \w:代表[0-9 a-z A-Z]
			 */
		</script>
	</head>
	<body onload="YZM()">
		<h1 align="center">注册页面</h1>
		<hr />
		<form action="" method="get">		
		<!--普通文本框-->
		<!--表格的格式-->
			<table align="center" border="0" cellspacing="20px">
				<tr>
					<td>用户名：</td>
					<td>
						<input type="text" name="uname" id="uname" value="" alt="用户名" placeholder="3-5位汉字" onblur="checkName()"/>
						<span id='uname_span'>*用户名必须是3-5位汉字</span>
					</td>
				</tr>			
				<!--密码框-->
				<tr>
					<td>密&nbsp;码</td>
					<td>
						<input type="password" name="pwd" id="pwd" value="" alt="密码" placeholder="3-6位数字" onblur="checkPwd()"/>
						<span id="pwd_span"></span>
					</td>
				</tr>			
				<!--手机框-->
				<tr>
					<td>手机号：</td>
					<td>
						<input type="text" name="phone" id="phone" alt="手机号码" onblur="checkPhone()"/>
						<span id="phone_span"></span>
					</td>
				</tr>				
				<!--邮箱输入框-->
				<tr>
					<td>邮&nbsp;箱：</td>
					<td>
						<input type="text" name="email" id="email" alt="邮箱地址" onblur="checkEmail()"/>
						<span id="email_span"></span>
					</td>
				</tr>				
				<!--性别输入框-->
				<tr>
					<td>性&nbsp;别：</td>
					<td>
					<input type="radio" name="sex" value="1" onclick="checkSex()"/> 男
					<input type="radio" name="sex" value="0" onclick="checkSex()" /> 女
					<span id="sex_span"></span>
					</td>
				</tr>				
				<!--爱好选择-->
				<tr>
				<td>爱&nbsp;好：</td>
					<td>
						<input type="checkbox"value="1" name="hobby" onclick="checkHobby()"/>唱歌
						<input type="checkbox"value="2" name="hobby" onclick="checkHobby()"/>睡觉
						<input type="checkbox"value="3" name="hobby" onclick="checkHobby()"/>LOL <br />
						<input type="checkbox"value="4" name="hobby" onclick="checkHobby()"/>旅行
						<input type="checkbox"value="5" name="hobby" onclick="checkHobby()"/>高尔夫
						<input type="checkbox"value="6" name="hobby" onclick="checkHobby()"/>篮球 <br />
						<span id="hobby_span"></span>
					</td>
				</tr>
				
				<!--籍贯选择-->
				<tr>
				<td>籍&nbsp;贯：</td>
					<td>
						<select >
						<option selected="selected">---请选择---</option>
						<option value="1">广东</option>
						<option value="2">湖南</option>
						<option value="3">湖北</option>
						<option value="4">河南</option>
						<option value="5">河北</option>
						</select>
					</td>
				</tr>
				
				<!--验证码输入框-->
				<tr height="35px">
					<td>验证码</td>
					<td>
						<input type="number" name="yzm"  id="yzm" value="" onblur="checkYZM()"/>
						<span id="yzm_span"></span><br />
						<span id="yzm_span2"></span>
					</td>
				</tr>
				
				<!--个人介绍输入框-->
				<tr>
					<td>个人介绍：</td>
					<td align="center">
						<!--align="center">代表全部东西都在中间-->
						<textarea rows="15" cols="30" onblur="checkIntroduce()"></textarea><br />
						<span id="introduce_span"></span><br />
						<input type="checkbox"value="7" />是否同意本公司协议<br />
						<input type="submit" value="注册" /><br />
						
						
					</td>
				</tr>
			</table>
		</form>
	</body>
</html>

Python 全系列/第七阶段：网页编程基础/JavaScript 3900楼

同学您好