这里common如果是创建在captcha_app下的话，路径就要写

from .common.captcha_4char import capcha

#测试单例模式

class MySingleton:
    __obj = None        #类属性

    def __new__(cls,*args,**kwargs):
        if cls.__obj ==None:
            cls.__obj = object.__new__(cls)

            return cls.__obj
    def __init__(self,name):

        print("init....")
        self.name = name


a = MySingleton("aa")
b = MySingleton("bb")
print(a)
print(b)

老师，代码一样，但是结果不一样

老师，我这个填入登录名和密码后就报错，这个怎么改啊

老师，请问线程的联合和方法有什么区别吗？

我上传的是一个jpg文件 都是乱码。。。

老师，网盘下载的文档只有目录，没有老师的课件资料，可以和讲课老师反馈一下吗

测试调用提供者服务报以下错：连接超时

2020-09-14 17:39:32.425 ERROR 19208 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Filtered request failed.] with root cause

java.net.SocketTimeoutException: connect timed out
	at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) ~[na:1.8.0_251]
	at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85) ~[na:1.8.0_251]
	at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_251]
	at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_251]
	at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_251]
	at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) ~[na:1.8.0_251]
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_251]
	at java.net.Socket.connect(Socket.java:606) ~[na:1.8.0_251]
	at redis.clients.jedis.Connection.connect(Connection.java:181) ~[jedis-3.1.0.jar:na]
	at redis.clients.jedis.BinaryClient.connect(BinaryClient.java:100) ~[jedis-3.1.0.jar:na]
	at redis.clients.jedis.BinaryJedis.connect(BinaryJedis.java:1866) ~[jedis-3.1.0.jar:na]
	at redis.clients.jedis.JedisFactory.makeObject(JedisFactory.java:117) ~[jedis-3.1.0.jar:na]
	at org.apache.commons.pool2.impl.GenericObjectPool.create(GenericObjectPool.java:889) ~[commons-pool2-2.7.0.jar:2.7.0]
	at org.apache.commons.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:424) ~[commons-pool2-2.7.0.jar:2.7.0]
	at org.apache.commons.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:349) ~[commons-pool2-2.7.0.jar:2.7.0]
	at redis.clients.jedis.util.Pool.getResource(Pool.java:50) ~[jedis-3.1.0.jar:na]
	at redis.clients.jedis.JedisPool.getResource(JedisPool.java:234) ~[jedis-3.1.0.jar:na]
	at org.crazycake.shiro.RedisManager.getJedis(RedisManager.java:35) ~[shiro-redis-3.2.3.jar:na]
	at org.crazycake.shiro.WorkAloneRedisManager.get(WorkAloneRedisManager.java:50) ~[shiro-redis-3.2.3.jar:na]
	at org.crazycake.shiro.RedisSessionDAO.doReadSession(RedisSessionDAO.java:152) ~[shiro-redis-3.2.3.jar:na]
	at org.apache.shiro.session.mgt.eis.AbstractSessionDAO.readSession(AbstractSessionDAO.java:168) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.session.mgt.DefaultSessionManager.retrieveSessionFromDataSource(DefaultSessionManager.java:236) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.session.mgt.DefaultSessionManager.retrieveSession(DefaultSessionManager.java:222) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.session.mgt.AbstractValidatingSessionManager.doGetSession(AbstractValidatingSessionManager.java:118) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.session.mgt.AbstractNativeSessionManager.lookupSession(AbstractNativeSessionManager.java:148) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.session.mgt.AbstractNativeSessionManager.getSession(AbstractNativeSessionManager.java:140) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.mgt.SessionsSecurityManager.getSession(SessionsSecurityManager.java:156) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.mgt.DefaultSecurityManager.resolveContextSession(DefaultSecurityManager.java:456) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.mgt.DefaultSecurityManager.resolveSession(DefaultSecurityManager.java:442) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.mgt.DefaultSecurityManager.createSubject(DefaultSecurityManager.java:338) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.subject.Subject$Builder.buildSubject(Subject.java:846) ~[shiro-core-1.3.2.jar:1.3.2]
	at org.apache.shiro.web.subject.WebSubject$Builder.buildWebSubject(WebSubject.java:148) ~[shiro-web-1.5.3.jar:1.5.3]
	at org.apache.shiro.web.servlet.AbstractShiroFilter.createSubject(AbstractShiroFilter.java:292) ~[shiro-web-1.5.3.jar:1.5.3]
	at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:359) ~[shiro-web-1.5.3.jar:1.5.3]
	at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) ~[shiro-web-1.5.3.jar:1.5.3]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1594) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_251]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_251]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.33.jar:9.0.33]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_251]

麻烦老师下载附件查看

老师你好

垃圾=没有被变量引用的对象

清除垃圾的方法：把null赋给变量，不让任何变量指向对象

那如果我创建了一个对象，但是我没赋给任何变量，这个对象就被JVM给清楚了？等于没创建吗？

//修改
obj.name='张先生';
obj['height']='170cm';
console.log(obj);

这两个obj，修改方式什么时候是

obj.name='张先生'

什么时候是

obj['height']='170cm';

老师您好我想问一下那个.fooetr-link ul标签下的line-height属性是不是写错了，后面没有写单位px

老师，这个问题的解决思路和方法是什么？

麻烦老师了

哎呀，老师，这就没有了，呜呜。