请问下面这串代码,super()的作用是什么,我记得super是之类直接访问父类对象,下面这个代码里好像没有继承
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> div{ width: 20px; height: 20px; border: 1px solid black; position: absolute; } </style> </head> <body> <input type="range" min="0" max="100" value="50"> <div></div> <script> var input=document.querySelector("input"); var div=document.querySelector("div"); input.onmounsemove=function () { console.log("(x,y):("+event.clientX+","+event.clientY+")"); } </script> </body> </html>
本视频6分57秒,我的代码和老师一摸一样但是出不来效果,“event”这个单词显示有删除线,不知道是什么意思,是因为这个显示不出效果吗?怎样才能没有删除线
老师,我在做<embed>音频时,加入的原来的音频是.m4a格式的,出现了乱码(如下)
代码如下:
但是将音频格式改为.mp3就正确,能够播放出来了,
所以是怎么回事呢?是不支持m4a格式的么?但在做<audio>的时候是可以播放出m4a格式的音频。
老师,我这个浏览器总是报错,我不知道哪里写错了。
<style> #div1{ background:red; width:100px; height:100px; } #div2{ background:green; width:50px; height:50px; } </style> <body> <div id="div1" > <div id="div2" > </div></div> <script> var div1=document.querySelector('#div1') var div2=document.querySelector('#div2') function test(){ console.log("文本3") } div2.attachEvent('onclick',test); div2.attachEvent("onclick",function(){ console.log("文本1") }) </script> </body>
讲课视频中,是接口引用指向实例对象 Test_A
为什么,用类引用指向实例对象Test_A,就不可以呢
老师,这里把移除代码写在前面,为什么函数还会执行一遍?我理解代码是自上而下执行,不会打印出才对,当div2移除成功,为什么点击div2部分,div1函数还会执行呢?我的理解是移除后点击div2部分div1不会执行。
<style> #div1{ background:red; width:100px; height:100px; } #div2{ background:green; width:50px; height:50px; } </style> <body> <div id="div1" onclick="te()">eee <div id="div2" onclick="te2();te3()">wen </div> </div> <span>wen</span> <script> var div1=document.querySelector('#div1') var div2=document.querySelector('#div2') function te(){ console.log("文本") } function te2(){ div2.setAttribute("onclick","null"); console.log("文本2"); } function te3(){ div2.setAttribute("onclick","null"); console.log("文本3"); } </script> </body>
老师,这里是因为这个函数为监听事件,决定了这个是事件捕获吗?除了这个自下而上的效果上区分,还可以怎么区分哪些算是事件捕获,哪些算是冒泡事件。
我第十八行这么写居然对了,但是我写 Outer2.Inner2 inn2=new Outer2().new Inner2();反而会错为什么?
对于万能参数 小括号填的怎么确定,从哪看?
参数后不用填的是显示了xxx=xxx 这样的吗
老师您好,每次一到这就卡。。。。。。 怎么解决
这种注释是什么类型的注释,怎么操作出来的,快捷键是什么
请问创建类和创建对象是一回事吗?
如果不是,那么在它们在代码中如何区别?
问题解决了..........................................
启动common_item错误代码如下,
TxManager启动正常,
防火墙已关,
org.springframework.beans.factory.BeanDefinitionStoreException: Failed to process import candidates for configuration class [com.bjsxt.item.CommonItemApplication]; nested exception is java.io.FileNotFoundException: class path resource [com/codingapi/txlcn/txmsg/MessageConfiguration.class] cannot be opened because it does not exist at org.springframework.context.annotation.ConfigurationClassParser.processImports(ConfigurationClassParser.java:596) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:302) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:242) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:199) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:167) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:315) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:232) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:275) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:95) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:705) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:531) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:742) ~[spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:389) ~[spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:311) ~[spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1213) ~[spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1202) ~[spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at com.bjsxt.item.CommonItemApplication.main(CommonItemApplication.java:18) ~[classes/:na] Caused by: java.io.FileNotFoundException: class path resource [com/codingapi/txlcn/txmsg/MessageConfiguration.class] cannot be opened because it does not exist at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:180) ~[spring-core-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.core.type.classreading.SimpleMetadataReader.<init>(SimpleMetadataReader.java:51) ~[spring-core-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:103) ~[spring-core-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.boot.type.classreading.ConcurrentReferenceCachingMetadataReaderFactory.createMetadataReader(ConcurrentReferenceCachingMetadataReaderFactory.java:86) ~[spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.type.classreading.ConcurrentReferenceCachingMetadataReaderFactory.getMetadataReader(ConcurrentReferenceCachingMetadataReaderFactory.java:73) ~[spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:81) ~[spring-core-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.annotation.ConfigurationClassParser.asSourceClass(ConfigurationClassParser.java:682) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.annotation.ConfigurationClassParser.asSourceClasses(ConfigurationClassParser.java:661) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.context.annotation.ConfigurationClassParser.processImports(ConfigurationClassParser.java:567) ~[spring-context-5.1.8.RELEASE.jar:5.1.8.RELEASE] ... 17 common frames omitted
老师为什么下面这个类不加static上面的创建对面就会报错,这是为什么
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