有效沟通问答-【官方】百战程序员_IT在线教育培训机构

class A:
    def __init__(self):
        print("A的构造方法")

    def say(self):
        print("A:",self)
        print("say AAA")

class B(A):  #B中使用了A的方法
    def __int__(self):
        # A.__init__(self)
        super(B,self).__init__()  # 调用父类的构造方法
        print("B的构造方法")

    def say(self):
        super().say()  # 通过super()调用父类的方法  即相当于在原来的方法上有添加
        print("say BBB")

b = B()
b.say()

老师，麻烦帮我看一下为什么按照老师的代码来敲，但是输出结果老师能输入“B的构造方法”，但是我这边自己尝试了之后却总是打不出来

Python 全系列/第一阶段：Python入门/面向对象 2102楼

老师请问视频里：

当newCapacity等于15时，执行完第一个if语句15-10<0返回为false之后为什么不执行第二个if语句？

而是直接copy了呢？

JAVA 全系列/第二阶段：JAVA 基础深化和提高/容器（旧） 2103楼

老师，如何爬取移动端的数据，我fidder现在已经能够抓到移动端的数据，但是不知道代码这些应该怎么写

Python 全系列/第十四阶段：Python 爬虫开发/动态数据抓取 2104楼

#encoding=utf-8
from threading import Thread
from time import sleep
def func1(name):
    for i in range(4):
        print(f"线程：{name}:{i}")
        sleep(1)  #每打一个暂停一下
if __name__=="__main__":
    print("主线程，start")
    #创建线程
    t1=Thread(target=func1,args=("t1,"))
    t2=Thread(target=func1,args=("t2,"))
    #启动线程
    t1.start()
    t2.start()
    print("主线程，end")

老师，为什么我这个报错了呀，还有为啥第6行要加f啊？

Python 全系列/第三阶段：Python 网络与并发编程/并发编程 2105楼

用input输入数字后如何让用一个参数或者变量接收输入这个值，举个例子，谢谢老师.

Python 全系列/第一阶段：Python入门/编程基本概念 2106楼

老师你看我在做打印空心正方形时，我用的这个思路打印，就是把i==0和把i==9和j==0和j==9的打印出来，写了代码后发现，有些不正确，我也想不出哪不对

一.代码

/**
 * 打印出空心 10*10 正方形
 */
public class Test22 {
    public static void main(String[] args){
        for (int i =0;i<10;i++){
            for(int j =0;j<10;j++){
                if (i==0||i==9||j==0||j==9){
                    System.out.print("*"+"\t");
                }

            }
            System.out.println();
        }
    }
}

二.代码运行截图

JAVA 全系列/第一阶段：JAVA 快速入门/控制语句、方法、递归算法 2107楼

获取key的低16位去比较hascode的高16位,然后取与或运算相同为0不同为1,返回hash值,然后把数组长度16-1的二进制去进行运算hash值返回的二进制转换为10进制就是数组索引了对吗

JAVA 全系列/第二阶段：JAVA 基础深化和提高/容器（旧） 2108楼

刚刚鼠标右击，不知道怎么了，现在每次要运行就这样了

Python 全系列/第二阶段：Python 深入与提高/异常机制 2109楼

springbootjdbc.zip

老师这个项目里报了这个错误怎么解决呢？找了好久错误没有找到

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'usersController': Unsatisfied dependency expressed through field 'usersService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'usersServiceImpl': Unsatisfied dependency expressed through field 'usersDao'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'usersDaoImpl': Unsatisfied dependency expressed through field 'jdbcTemplate'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'dataSourceScriptDatabaseInitializer' defined in class path resource [org/springframework/boot/autoconfigure/sql/init/DataSourceInitializationConfiguration.class]: Unsatisfied dependency expressed through method 'dataSourceScriptDatabaseInitializer' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Generic.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: com.mysql.jdbc.Driver

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:659) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:639) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1431) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:619) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:953) ~[spring-beans-5.3.16.jar:5.3.16]

at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.16.jar:5.3.16]

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.16.jar:5.3.16]

at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.4.jar:2.6.4]

at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:740) [spring-boot-2.6.4.jar:2.6.4]

at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:415) [spring-boot-2.6.4.jar:2.6.4]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-2.6.4.jar:2.6.4]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:1312) [spring-boot-2.6.4.jar:2.6.4]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301) [spring-boot-2.6.4.jar:2.6.4]

at com.bjsxt.springbootjdbc.SpringbootjdbcApplication.main(SpringbootjdbcApplication.java:10) [classes/:na]

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'usersServiceImpl': Unsatisfied dependency expressed through field 'usersDao'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'usersDaoImpl': Unsatisfied dependency expressed through field 'jdbcTemplate'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'dataSourceScriptDatabaseInitializer' defined in class path resource [org/springframework/boot/autoconfigure/sql/init/DataSourceInitializationConfiguration.class]: Unsatisfied dependency expressed through method 'dataSourceScriptDatabaseInitializer' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Generic.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javax.sql.DataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: com.mysql.jdbc.Driver