# 重新建立索引，并添加缺失值
g = pd.read_excel("stu_data.xlsx",sheetname="Sheet1" ,index_col="date")
# print(g)
index_new=pd.date_range("2005/1/1","2015/1/30" )
print(index_new)
h=g.reindex(index_new,method="bfill" )
print(h)

ValueError: cannot reindex a non-unique index with a method or limit

为什么一直报错？

老师，我安装mysql的时候这个应该选哪个

这里直接把图片放进image目录中然后把路径改成(image/尚学堂.jpg),不是一样可以支持跨平台吗?为什么要创建image目录后在去获取它的绝对路径呢?相比这样用绝对路径有什么更好作用吗?

请问老师，为什老师的代码在爬取不同网页时，有些会报错（报的错是啥意思呀），有些不会

package com;

import java.io.*;
import java.net.URL;

public class TestURL2 {
    public static void main(String[] args) throws IOException {
        URL url=new URL("https://www.baidu.com/");
        InputStream is=url.openStream();
        BufferedReader br=new BufferedReader(new InputStreamReader(is,"utf-8"));
        BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream("index.html"),"utf-8"));
        String line=null;
        while((line=br.readLine())!=null){
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        bw.close();
    }
}

package com;

import java.io.*;
import java.net.URL;

public class TestURL2 {
    public static void main(String[] args) throws IOException {
        URL url=new URL("https://www.bilibili.com/");
        InputStream is=url.openStream();
        BufferedReader br=new BufferedReader(new InputStreamReader(is,"utf-8"));
        BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream("index.html"),"utf-8"));
        String line=null;
        while((line=br.readLine())!=null){
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        bw.close();
    }
}

把依赖全写到pojo里有没有事，然后mapper调用pojo依赖，service调用mapper依赖，controller调用service依赖。

老师 问一下between and 和 in 之间的区别 都是表示范围，为什么查到的数据不一样？

select last_name ,salary from employees where salary not in (5000,12000);

select last_name , salary from employees where salary not between 5000 and 12000;

a=[10,20,30,40,50,60]
for x in a:
        print(x,end="#")

这段代码中print（x，end=“#”）

end=“#”这是什么意思

老师，我什么我又定了一个mainth2还是一样的

一、过程描述

这块是springboot_dubbo的provider部分

启动SpringBootApplication之后报错如上图

根据翻译和百度查到slf4j有两个，冲突导致

老师，麻烦问一下属性和方法的含义和不同。

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-03-17 14:15:58.981 ERROR 20832 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userServiceImpl': Injection of @Reference dependencies is failed; nested exception is java.lang.IllegalStateException: zookeeper not connected
	at com.alibaba.spring.beans.factory.annotation.AbstractAnnotationBeanPostProcessor.postProcessPropertyValues(AbstractAnnotationBeanPostProcessor.java:146) ~[spring-context-support-1.0.6.jar:na]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1427) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:882) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
	at com.bjsxt.consumer.UserConsumerApplication.main(UserConsumerApplication.java:10) [classes/:na]
Caused by: java.lang.IllegalStateException: zookeeper not connected
	at org.apache.dubbo.remoting.zookeeper.curator.CuratorZookeeperClient.<init>(CuratorZookeeperClient.java:83) ~[dubbo-remoting-zookeeper-2.7.6.jar:2.7.6]
	at org.apache.dubbo.remoting.zookeeper.curator.CuratorZookeeperTransporter.createZookeeperClient(CuratorZookeeperTransporter.java:26) ~[dubbo-remoting-zookeeper-2.7.6.jar:2.7.6]
	at org.apache.dubbo.remoting.zookeeper.support.AbstractZookeeperTransporter.connect(AbstractZookeeperTransporter.java:70) ~[dubbo-remoting-zookeeper-2.7.6.jar:2.7.6]
	at org.apache.dubbo.remoting.zookeeper.ZookeeperTransporter$Adaptive.connect(ZookeeperTransporter$Adaptive.java) ~[dubbo-common-2.7.6.jar:2.7.6]
	at org.apache.dubbo.configcenter.support.zookeeper.ZookeeperDynamicConfiguration.<init>(ZookeeperDynamicConfiguration.java:70) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.configcenter.support.zookeeper.ZookeeperDynamicConfigurationFactory.createDynamicConfiguration(ZookeeperDynamicConfigurationFactory.java:37) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.common.config.configcenter.AbstractDynamicConfigurationFactory.lambda$getDynamicConfiguration$0(AbstractDynamicConfigurationFactory.java:39) ~[dubbo-common-2.7.6.jar:2.7.6]
	at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660) ~[na:1.8.0_261]
	at org.apache.dubbo.common.config.configcenter.AbstractDynamicConfigurationFactory.getDynamicConfiguration(AbstractDynamicConfigurationFactory.java:39) ~[dubbo-common-2.7.6.jar:2.7.6]
	at org.apache.dubbo.common.config.configcenter.DynamicConfiguration.getDynamicConfiguration(DynamicConfiguration.java:223) ~[dubbo-common-2.7.6.jar:2.7.6]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.prepareEnvironment(DubboBootstrap.java:857) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.startConfigCenter(DubboBootstrap.java:603) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.useRegistryAsConfigCenterIfNecessary(DubboBootstrap.java:671) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.initialize(DubboBootstrap.java:509) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.init(DubboBootstrap.java:494) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.config.ReferenceConfig.init(ReferenceConfig.java:190) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.config.ReferenceConfig.get(ReferenceConfig.java:158) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.config.spring.beans.factory.annotation.ReferenceAnnotationBeanPostProcessor.getOrCreateProxy(ReferenceAnnotationBeanPostProcessor.java:274) ~[dubbo-2.7.6.jar:2.7.6]
	at org.apache.dubbo.config.spring.beans.factory.annotation.ReferenceAnnotationBeanPostProcessor.doGetInjectedBean(ReferenceAnnotationBeanPostProcessor.java:143) ~[dubbo-2.7.6.jar:2.7.6]
	at com.alibaba.spring.beans.factory.annotation.AbstractAnnotationBeanPostProcessor.getInjectedObject(AbstractAnnotationBeanPostProcessor.java:359) ~[spring-context-support-1.0.6.jar:na]
	at com.alibaba.spring.beans.factory.annotation.AbstractAnnotationBeanPostProcessor$AnnotatedFieldElement.inject(AbstractAnnotationBeanPostProcessor.java:539) ~[spring-context-support-1.0.6.jar:na]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:130) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at com.alibaba.spring.beans.factory.annotation.AbstractAnnotationBeanPostProcessor.postProcessPropertyValues(AbstractAnnotationBeanPostProcessor.java:142) ~[spring-context-support-1.0.6.jar:na]
	... 17 common frames omitted
Caused by: java.lang.IllegalStateException: zookeeper not connected
	at org.apache.dubbo.remoting.zookeeper.curator.CuratorZookeeperClient.<init>(CuratorZookeeperClient.java:80) ~[dubbo-remoting-zookeeper-2.7.6.jar:2.7.6]
	... 39 common frames omitted

老师，这是什么错误？

class Man:
    def eat(self):
        print("饿了，吃饭")

class Chinese(Man):
    def eat(self):
        print("中国人吃饭用筷子")

class English(Man):
    def eat(self):
        print("英国人吃饭用刀叉")

class Indian(Man):
    def eat(self):
        print("印度人吃饭也用手")

def manEat(m):
    if isinstance(m,Man):
        m.eat
    else:
        print("不能吃饭")

manEat(Chinese())

老师，为什么我的代码 打印什么都没有的，讲讲问题点

怎么回事？

老师 这里代码不全呀，每个用户登录时显示的菜单权限都一样