老师好，在将商品加入购物车的时候，我发现，并没有向后端传递商品数量num的参数，请问怎么解决？

老师，一个类继续另外一个类不应该是在初始化中显式调用吗？

问题点：明明设置了打印键和之间存在空格，为什么打印结果只有第一行“”world 456“”输出的键和值之间有空格，而剩下的键java和值567   都没有打印出键和值之间的空格呢

代码如下：

import java.util.HashMap;

import java.util.Map.Entry;

import java.util.Set;

public class TestMap {

public static void main(String[] args) {

HashMap<String, Integer> hm = new HashMap<String, Integer>();

hm.put("hello", 123);

hm.put("world", 456);

hm.put("java", 567);

// 遍历1.0

Set<String> set = hm.keySet();//获取所有键的集合

for (String str : set) {

System.out.println(str+"\t"+hm.get(str));//根据键去获取值str是迭代器作为键来被获取值

}

System.out.println("\n*********************************************\n");

// 遍历2.0 Entry<String, Integer>键值关系的类型

Set<Entry<String, Integer>> entry = hm.entrySet();//Entry为接口被定义在Map中

for (Entry<String, Integer> ent : entry) {//Set集合中每一个元素都是Entry类型

System.out.println(ent.getKey()+"\t"+ent.getValue());//获取键值关系

}

}

}

输出结果如下：

项目目标：求1x2x3x4...........x100的值

import java.util.*;
public class Test_While {
	public static void main(String[]args) {
		int a=1;
		int sum=1;
		while(a<=100){
			sum=sum*a;
			a++;
		}
		
		System.out.println(sum);
		
	}
}

运行结果：

请问老师为什么显示的是0呀？

我的逻辑是sum=1x1   sum=1  a++=2

                sum=1x2    sum=2  a++=3

                sum=2x3    sum=6  a++=4

以此类推然后得出1x2x3x4...........x100的结果

老师分享一下课件资料啊。这个知识点对现在阶段的我很重要啊！

老师为什么我能连接虚拟机，但是命令好像执行不太对，左边是虚拟机上的ll命令可以看到相关的目录信息，Xshell上写ll命令就不行

解决了。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。

十二月 10, 2019 5:16:42 下午 org.springframework.test.context.support.AbstractTestContextBootstrapper getDefaultTestExecutionListenerClassNames
信息: Loaded default TestExecutionListener class names from location [META-INF/spring.factories]: [org.springframework.test.context.web.ServletTestExecutionListener, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener, org.springframework.test.context.support.DependencyInjectionTestExecutionListener, org.springframework.test.context.support.DirtiesContextTestExecutionListener, org.springframework.test.context.transaction.TransactionalTestExecutionListener, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener]
十二月 10, 2019 5:16:42 下午 org.springframework.test.context.support.AbstractTestContextBootstrapper instantiateListeners
信息: Could not instantiate TestExecutionListener [org.springframework.test.context.web.ServletTestExecutionListener]. Specify custom listener classes or make the default listener classes (and their required dependencies) available. Offending class: [javax/servlet/ServletContext]
十二月 10, 2019 5:16:42 下午 org.springframework.test.context.support.AbstractTestContextBootstrapper getTestExecutionListeners
信息: Using TestExecutionListeners: [org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener@1daadbf7, org.springframework.test.context.support.DependencyInjectionTestExecutionListener@3c4f4458, org.springframework.test.context.support.DirtiesContextTestExecutionListener@78100c56, org.springframework.test.context.transaction.TransactionalTestExecutionListener@659a1fae, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener@69960c9e]
十二月 10, 2019 5:16:42 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [ApplicationContext.xml]
十二月 10, 2019 5:16:42 下午 org.springframework.test.context.TestContextManager prepareTestInstance
严重: Caught exception while allowing TestExecutionListener [org.springframework.test.context.support.DependencyInjectionTestExecutionListener@3c4f4458] to prepare test instance [com.yangge.test.UsersDaoImplTest@188553b2]
java.lang.IllegalStateException: Failed to load ApplicationContext
 at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)
 at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83)
 at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117)
 at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
 at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:228)
 at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:217)
 at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:276)
 at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
 at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:278)
 at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:236)
 at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)
 at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
 at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
 at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
 at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
 at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
 at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
 at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
 at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
 at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180)
 at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
 at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 41 in XML document from class path resource [ApplicationContext.xml] is invalid; nested exception is org.xml.sax.SAXParseException; lineNumber: 41; columnNumber: 102; cvc-complex-type.2.4.a: 发现了以元素 'bean' 开头的无效内容。应以 '{"http://www.springframework.org/schema/beans":description, "http://www.springframework.org/schema/beans":meta, "http://www.springframework.org/schema/beans":constructor-arg, "http://www.springframework.org/schema/beans":property, "http://www.springframework.org/schema/beans":qualifier, "http://www.springframework.org/schema/beans":lookup-method, "http://www.springframework.org/schema/beans":replaced-method, WC[##other:"http://www.springframework.org/schema/beans"]}' 之一开头。
 at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:399)
 at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:336)
 at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:304)
 at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:181)
 at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:217)
 at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:188)
 at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:252)
 at org.springframework.test.context.support.AbstractGenericContextLoader.loadBeanDefinitions(AbstractGenericContextLoader.java:253)
 at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:122)
 at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60)
 at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:109)
 at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:261)
 at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98)
 at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116)
 ... 25 more
Caused by: org.xml.sax.SAXParseException; lineNumber: 41; columnNumber: 102; cvc-complex-type.2.4.a: 发现了以元素 'bean' 开头的无效内容。应以 '{"http://www.springframework.org/schema/beans":description, "http://www.springframework.org/schema/beans":meta, "http://www.springframework.org/schema/beans":constructor-arg, "http://www.springframework.org/schema/beans":property, "http://www.springframework.org/schema/beans":qualifier, "http://www.springframework.org/schema/beans":lookup-method, "http://www.springframework.org/schema/beans":replaced-method, WC[##other:"http://www.springframework.org/schema/beans"]}' 之一开头。
 at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:198)
 at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134)
 at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:437)
 at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:368)
 at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:325)
 at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator$XSIErrorReporter.reportError(XMLSchemaValidator.java:458)
 at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.reportSchemaError(XMLSchemaValidator.java:3237)
 at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:1796)
 at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.startElement(XMLSchemaValidator.java:746)
 at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:378)
 at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2778)
 at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606)
 at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:117)
 at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
 at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848)
 at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777)
 at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
 at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:243)
 at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:347)
 at org.springframework.beans.factory.xml.DefaultDocumentLoader.loadDocument(DefaultDocumentLoader.java:76)
 at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadDocument(XmlBeanDefinitionReader.java:429)
 at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:391)
 ... 38 more

老师这是提示路径错误吗 但是我得路径也没错啊

package com.yangge.test;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.annotation.Transactional;

import com.yangge.dao.UsersDao;
import com.yangge.pojo.Users;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:ApplicationContext.xml")
public class UsersDaoImplTest {
 @Autowired
 private UsersDao usersDao;
 @Test
 @Transactional
 public void insert(){
  Users users =new Users(1,"寮犱笁",22);
  usersDao.insertUsers(users);
 }

}

在src目录下得

代码区：

/**
 * 测试递归
 * @author 一姐姐
 *
 */
public class TestDigui1 {
        public static void main(String[]args) {
        //打印实心10*10正方形
        for(int m=0;m<=10;m++);
            for(int n=0;n<=10;n++) {
                    System.out.print("*  ");
            }
            System.out.println();
        }
        System.out.println("##########################");
      //打印空心10*10正方形
        for (int p=1;p<=10;p++) {
            if(p>1&&p<10) {
                System.out.println("*                  *");
            }else {
                System.out.println("*  *  *  *  *  *  *  *  *  *");
            }
        }
}

运行结果

Exception in thread "main" java.lang.Error: Unresolved compilation problem:

    at TestDigui1.main(TestDigui1.java:8)

老师，这是哪里错啦？

老师，这为什么会请求超时啊，都设置好的的，我ping了一下一网段的pc1和二网段的pc5通不通，结果请求超时

全英文版。。。那个中文包不知道放哪去，没有那个lib文件夹

老师，我这个将程序作为广播方，将网络调试助手作为接收方，为什么网络调试助手没收到消息啊

# udp广播
import socket
addr = ('<broadcast>', 8888)
s =socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST,1)
s.sendto(b'nihao', addr)

import pygame
screen_width = 700
screen_height = 400
BG_color = pygame.Color(0, 0, 0)
Text_COLOR = pygame.Color(255, 0, 0)

class MainGame():
    window = None

    def __init__(self):
        pass

    def startGame(self):
        # 初始化显示模块
        pygame.display.init()
        # 初始化显示窗口
        MainGame.window = pygame.display.set_mode([screen_width, screen_height])
        pygame.display.set_caption("坦克大战1.0")
        while True:
            # 给窗口设置填充色
            self.getEvent()
            MainGame.window.blit(self.getTextSurface('剩余敌方坦克数量%d'%6), (10, 10))
            MainGame.window.fill(BG_color)
            pygame.display.update()

    def endGame(self):
        pass

    def getTextSurface(self, text):
# 初始化字体模块
        pygame.font.init()
        # 获取字体font对象
        pygame.font.get_fonts()

        s= pygame.font.SysFont("kaiti", 18)
        #绘制文本信息
        textSurface = s.render(text, True, Text_COLOR)
        return textSurface

    def getEvent(self):
        #获取所有事件
        eventList = pygame.event.get()
        #遍历事件
        for event in eventList:
# 判断按下的
            if event.type == pygame.QUIT:
                exit()



class Tank():
    def __init__(self):
        pass

    def move(self):
        pass

    def shot(self):
        pass

    def display(self):
        pass


# 我方坦克
class MyTank(Tank):
    def __init__(self):
        pass


class EnmeyTank(Tank):
    def __init__(self):
        pass


class Bullet():
    def __init__(self):
        pass

    def move(self):
        pass

    def displayBullet(self):
        pass


class Wall():
    def __init__(self):
        pass

    def displayWall(self):
        pass


class Explode():
    def __init__(self):
        pass

    def displayExplode(self):
        pass


class Music():
    def __init__(self):
        pass

    def playMusic(self):
        pass


if __name__ == "__main__":
    MainGame().startGame()

老师我这段代码没有报错，但是左上角却没有文本信息的显示，新surface没出来啊，帮忙看看，谢谢

public class test1 {
	public static void main(String[]args) {
		int sum01=0;
		int sum02=0;
		int i =1;
		while( i<=100) {
			i++;
			if(i%2==0) {
				sum01+=i;
			}else {
				sum02+=i;
			}
			
		}
		System.out.println("偶数和="+sum01);
		System.out.println("奇数和="+sum02);	
	}
}

为什么运算结果是偶数=2550，奇数=2600，哪边出了问题