代码：

package cn.sxt.game;

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;

import javax.imageio.ImageIO;

public class GameUtil {
	//工具类最好将构造器私有化。
	private GameUtil() {
	}
	
	public static Image getImage(String path) {
		BufferedImage bi =null;
		try {
			URL u=GameUtil.class.getClassLoader().getResource(path);
			bi=ImageIO.read(u);
		}catch(IOException e) {
			e.printStackTrace();
		}
		return bi;
	}
}

我的代码是照着敲的，为什么大部分报错，但是把这些都导入进去就不报错了，但是视频上很明显没有导入这些包的操作，因为我发现我的都要等他报错再导入，然后餐算解决，我想知道出现这样的情况是因为什么原因所导致？现在的我感觉和老师步骤不一致，所以让我很是烦恼，再加上是英文，看不懂，都不知道自己导入了什么

本章的学习资料中，没有上面件资源啊。老师分享下啊

老师为什么我输入 import jsonpickle的代码 显示不可以调用呢？

老师，我的代码按照视频中的敲的，但是出了问题，反复检查了几遍无结果还请老师帮忙看一下！

book.xsd中的代码：

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" >
	<xs:element name="books">
		<xs:complexType>   <!-- 复杂元素 -->
			<xs:sequence>
				<xs:element name="book" maxOccurs="unbounded"><!-- 第一个元素以及可以出现多个所以为unbounded -->
					<xs:complexType>
						<xs:sequence><!-- 子标签出现是有一定顺序的 -->
							<xs:element name="name" type="xs:string"></xs:element>
							<xs:element name="author" type="xs:string" ></xs:element>
							<xs:element name="price" type="xs:double"></xs:element>
						</xs:sequence>
						<xs:attribute name="id" type="xs:positiveInteger" use="required"></xs:attribute>
					</xs:complexType>
				</xs:element>
			</xs:sequence>
		</xs:complexType>
	</xs:element>
</xs:schema>

book.xml中的代码:

<?xml version="1.0" encoding="UTF-8"?>
<books xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:noNamespaceSchemaLocation="{book.xsd}">
	<book id="1001">
		<name>java开发实战</name>
		<author>江小欧</author>
		<price>99.9</price>
		
	</book>
	<book id="1002">
		<name>mysql从删库到跑路</name>
		<author>江小白</author>
		<price>89.7</price>
	</book>
</books>

Test类：

package cn.sxt.schema;

import java.io.File;
import java.io.IOException;

import javax.xml.bind.JAXBException;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;

import org.xml.sax.SAXException;

public class Test92 {
	public static void main(String[] args) throws SAXException {
		//1.创建SchemaFactory工厂
		SchemaFactory sch = SchemaFactory.newInstance("http://www.w3.org/2001/XMLSchema");
		//2.建立验证文件对象
		File schemaFile = new File("book.xsd");
		//3.利用SchemaFactory工厂对象，接收验证的文件对象，生成Schema对象
		Schema schema = sch.newSchema(schemaFile);
		//4.生产对此schema的验证器
		Validator validator = schema.newValidator();
		//5.要验证的数据(准备数据源)
		Source source = new StreamSource();
		//6.开始验证
		try {
			validator.validate(source);
			System.out.println("成功");
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("失败");
		}
	}
}

运行错误图：

信息: Illegal access: this web application instance has been stopped already. Could not load []. The following stack trace is thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access.

java.lang.IllegalStateException: Illegal access: this web application instance has been stopped already. Could not load []. The following stack trace is thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access.

at org.apache.catalina.loader.WebappClassLoaderBase.checkStateForResourceLoading(WebappClassLoaderBase.java:1305)

at org.apache.catalina.loader.WebappClassLoaderBase.getResource(WebappClassLoaderBase.java:986)

at com.mysql.cj.jdbc.AbandonedConnectionCleanupThread.checkContextClassLoaders(AbandonedConnectionCleanupThread.java:96)

at com.mysql.cj.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:69)

at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135)

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)

at java.base/java.lang.Thread.run(Thread.java:844)

浏览器显示无限循环重定向，不知道什么原因

有个疑问，为啥我两个打印出来的东西不一样呢？

代码如下：

class Solution:
    def __init__(self):
         self.c = []
    def twoSum(self,nums,target):
        i = 0
        j=len(nums)-1
        num = sorted(nums)
        while j>i:
            if num[i] + num[j] ==target:
                self.c.append([i,j])
                j -=1
            elif num[i] +num[j] < target:
                i += 1
            else:
                j -=1
        return self.c
a1 = Solution().twoSum([1,2,4,5,6],7)
print(a1)
print(Solution().c)

老师，代码是照着敲的，可是运行的时候提示 'Tank' object has no attribute 'imges'

代码如下：

运行结果：

老师，代码是照着敲的，可是运行的时候提示 'Tank' object has no attribute 'imges'

代码如下：

pygame
_display = pygame.display
COLOR_BLACK = pygame.Color(,,)    COLOR_RED = pygame.Color(,,)    version = MainGame():    window = SCREN_HWIDTH = SCREN_WIDTH = TANK_P1 = ():
        startGame():    _display.init()    MainGame.window = _display.set_mode([MainGame.SCREN_WIDTH,MainGame.SCREN_HWIDTH])    MainGame.TANK_P1 = Tank(, )  _display.set_caption(+ version)
        :
            MainGame.window.fill(COLOR_BLACK)    .getEvent()    MainGame.window.blit(.getTextSurface(%),(,))
            MainGame.TANK_P1.displayTanck()
            _display.update()  getEvent():    eventList = pygame.event.get()    event eventList:
            event.type == pygame.QUIT:
                .endGame()
            event.type ==  pygame.KEYDOWN:
                event.key == pygame.K_LEFT:    ()
                event.key == pygame.K_RIGHT:
                    ()
                event.key == pygame.K_UP:
                    ()
                event.key == pygame.K_DOWN:
                    ()
                event.key == pygame.K_SPACE:
                    ()
    getTextSurface(,text):
        pygame.font.init()
        font = pygame.font.SysFont(,)
        textSurface = font.render(text,,COLOR_RED)
        textSurface
    endGame():    ()
        ()    Tank():
    (,left,top):
        .iamges = {
            :pygame.image.load() , :pygame.image.load(),
            :pygame.image.load(),
            :pygame.image.load()
        }
        .directtion = .image = .imges[.directtion]    .rect = .image.get_rect()
        .rect.left = left
        .rect.top = top
    move():     shot():   displayTanck():        .image = .image[.directtion]
        MainGame.window.blit(.image,.rect)
MyTanck(Tank):    ():
        EnemyTank(Tank):    ():
        Bullet():    ():
        move():
        displayBulet():
        Explode():
    ():
        displayExplode():      Wall():    ():
        displayWall():
        Music():    ():
        MainGame().startGame()

运行结果：

老师，防火墙关闭了，环境变量也配置对了，Tomcat也启动成功了，为啥我就是访问不了呢？

pymysql
con=pymysql.connect()
cursor=con.cursor()
:
    spl=cursor.execute(sal)
    con.commit()
:
    ()
    con.rollback()
:
    con.close()

老师看看我这什么问题，我一执行就出现下面报错

Traceback (most recent call last):

  File "C:\Users\acer\AppData\Roaming\Python\Python37\site-packages\pymysql\connections.py", line 583, in connect

    **kwargs)

  File "C:\Program Files (x86)\Python37-32\lib\socket.py", line 707, in create_connection

    for res in getaddrinfo(host, port, 0, SOCK_STREAM):

  File "C:\Program Files (x86)\Python37-32\lib\socket.py", line 748, in getaddrinfo

    for res in _socket.getaddrinfo(host, port, family, type, proto, flags):

socket.gaierror: [Errno 11001] getaddrinfo failed

During handling of the above exception, another exception occurred:

Traceback (most recent call last):

  File "D:/python/pythondemo/com/插入数据.py", line 2, in <module>

    con=pymysql.connect('localhosrt','root','sen6263234','pythondemo',3306)

  File "C:\Users\acer\AppData\Roaming\Python\Python37\site-packages\pymysql\__init__.py", line 94, in Connect

    return Connection(*args, **kwargs)

  File "C:\Users\acer\AppData\Roaming\Python\Python37\site-packages\pymysql\connections.py", line 325, in __init__

    self.connect()

  File "C:\Users\acer\AppData\Roaming\Python\Python37\site-packages\pymysql\connections.py", line 630, in connect

    raise exc

pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on 'localhosrt' ([Errno 11001] getaddrinfo failed)")

                                        老师，因为我一开始装的时候虚拟驱动一直挂载不了，就卸载了，现在重装

                                    一直出现下面的问题无法安装，请问该如何解决？

--------------------------------------

老师怎么理解笔记的这句话：

如果未使用 ORDER BY 子句，排序次序就未定义，并且 Oracle 服务器可能对于相同查询的两次执行取回行的顺序不同。

老师，这个head命令，是只对数字文本起作用么？为啥我只让它显示12行，它统统都给我显示出来了..

引入图片时一定要把图片引到webstorm中吗，如果不用需要怎么做？