转义不是反斜杠\吗，文档是不是错了

视屏提到的springmvc是从哪看

# Frame是一个矩形区域 用来放置其它组件
f1 = Frame(root)
f1.pack()
f2 = Frame(root);f2.pack()

然而改成：

# Frame是一个矩形区域 用来放置其它组件
f1 = Frame(root).pack()
f2 = Frame(root).pack()

这两行代码有什么区别吗？ 不是可以这样简化的吗？

"C:\Program Files\Java\jdk-16.0.1\bin\java.exe" "-javaagent:F:\IntelliJ IDEA 2021.3\lib\idea_rt.jar=59331:F:\IntelliJ IDEA 2021.3\bin" -Dfile.encoding=UTF-8 -classpath F:\校园卡管理系统\demo1\springjdbcdemo\out\production\springjdbcdemo;D:\百战程序员java\SSM框架和项目开发\Spring\软件\lib\commons-logging-1.2.jar;D:\百战程序员java\SSM框架和项目开发\Spring\软件\lib\spring-tx-5.2.7.RELEASE.jar;D:\百战程序员java\SSM框架和项目开发\Spring\软件\lib\spring-core-5.2.7.RELEASE.jar;D:\百战程序员java\SSM框架和项目开发\Spring\软件\lib\spring-jdbc-5.2.7.RELEASE.jar;D:\百战程序员java\SSM框架和项目开发\Spring\软件\lib\spring-beans-5.2.7.RELEASE.jar;D:\百战程序员java\SSM框架和项目开发\Spring\软件\lib\mysql-connector-java-5.1.48.jar;D:\百战程序员java\SSM框架和项目开发\Spring\软件\lib\spring-context-5.2.7.RELEASE.jar;D:\百战程序员java\SSM框架和项目开发\Spring\软件\lib\spring-expression-5.2.7.RELEASE.jar com.bjsxt.test.addUsersTest

Wed Jan 19 14:41:22 CST 2022 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

Exception in thread "main" org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 237 milliseconds ago.  The last packet sent successfully to the server was 224 milliseconds ago.

at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:82)

at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:612)

at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:862)

at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:917)

at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:927)

at com.bjsxt.dao.impl.UsersDaoImpl.insertUsers(UsersDaoImpl.java:30)

at com.bjsxt.service.impl.UsersServiceImpl.addUsers(UsersServiceImpl.java:25)

at com.bjsxt.test.addUsersTest.main(addUsersTest.java:15)

Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 237 milliseconds ago.  The last packet sent successfully to the server was 224 milliseconds ago.

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:78)

at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)

at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)

at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990)

at com.mysql.jdbc.ExportControlled.transformSocketToSSLSocket(ExportControlled.java:201)

at com.mysql.jdbc.MysqlIO.negotiateSSLConnection(MysqlIO.java:4869)

at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1656)

at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1217)

at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2189)

at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2220)

at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2015)

at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:768)

at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:78)

at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)

at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)

at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:385)

at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:323)

at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)

at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:189)

at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriverManager(DriverManagerDataSource.java:155)

at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriver(DriverManagerDataSource.java:146)

at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnectionFromDriver(AbstractDriverBasedDataSource.java:205)

at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnection(AbstractDriverBasedDataSource.java:169)

at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:158)

at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:116)

at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:79)

... 7 more

Caused by: javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)

at java.base/sun.security.ssl.HandshakeContext.<init>(HandshakeContext.java:172)

at java.base/sun.security.ssl.ClientHandshakeContext.<init>(ClientHandshakeContext.java:98)

at java.base/sun.security.ssl.TransportContext.kickstart(TransportContext.java:238)

at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:434)

at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:412)

at com.mysql.jdbc.ExportControlled.transformSocketToSSLSocket(ExportControlled.java:186)

老师我想问一下出现这个异常怎么解决呀 我找了好久没找到问题....

s1s1s1 s2 s2namemajorheights2 s2s2height s2name s2major name height major

老师这样对吗

s1s1s1 s2 s2namemajorheights2 s2s2height s2name s2major name height major

老师这样对吗

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" /> 
    <script type="text/javascript" src="https://api.map.baidu.com/api?v=3.0&ak=FbonyatSbRvrD6W2ApVIpz5BGT9wE18a"></script>

    <title>Document</title>
    <style type="text/css">  
        html{height:100%}    
        body{height:100%;margin:0px;padding:0px}    
        #container{height:500px;width: 700px; border: 1px solid black;}    
    </style> 
</head>
<body>
    <div id="container"></div> 
    <button>加载</button>
    <script>
        var btn=document.querySelector('button');
        btn.onclick=function(){
            var map = new BMap.Map("container");    
var point = new BMap.Point(113.26512290418745, 23.154485582798717);    
map.centerAndZoom(point, 15);    
map.addControl(new BMap.NavigationControl());//平移缩放
//默认标注
// map.addEventListener('click',function(eve){
//     var tempMarker = new BMap.Marker(eve.point);        // 创建标注    
// map.addOverlay(tempMarker);  
// }


//------------------------自定义图标-------------------
var temPoint = new BMap.Point(113.26552290418745, 23.154485582798717);
var myIcon = new BMap.Icon("imgs/标注.gif", new BMap.Size(50, 50), {    
        // 指定定位位置。   
        // 当标注显示在地图上时，其所指向的地理位置距离图标左上    
        // 角各偏移10像素和25像素。您可以看到在本例中该位置即是   
        // 图标中央下端的尖角位置。    
        anchor: new BMap.Size(10, 25),    
        // 设置图片偏移。   
        // 当您需要从一幅较大的图片中截取某部分作为标注图标时，您   
        // 需要指定大图的偏移位置，此做法与css sprites技术类似。    
        imageOffset: new BMap.Size(-30, 10)   // 设置图片偏移    
    });      
    // 创建标注对象并添加到地图   
    var Mymarker = new BMap.Marker(temPoint, {icon: myIcon});    
    map.addOverlay(Mymarker);    
        }
    </script>
</body>
</html>

我的自定义图片怎么加载不了出来

请问下返回值类型是这个类,可以不可以自定义其他类型

老师，这里的urls导入路劲不对吗？老报错

function timesTampToTime(timestamp) {
var d = new Date(timestamp);
var year = d.getFullYear() + '-';
var month = d.getMonth() + 1 + '-';
var day = d.getDate() + ' ';
var hours = d.getHours() + ':';
var minute = d.getMinutes() + ':'
var second = d.getSeconds();
second >=10 ? d.getSeconds() : ('0' + d.getSeconds());
return year + month + day + hours + minute + second;
}
var result = timesTampToTime(1642529707845);
console.log(result)

2022-1-19 2:15:7

为什么0没有添加上呢

问题1:和1楼一样，5.47那个位置说的有点绕，应该是说在形参类型为byte数组时，read()方法返回的是读取到缓冲区（byte数组）的总字节数，当这个文件读到尾了没有可以读的东西的时候返回-1，达成结束条件

问题2:这个问题我看源码好像也没看懂。。

假设OldLu发了两百斤大米，我这个包20斤，第一次取取满了，用write方法将这个包里的米放回家里

但是我看write方法的源码里面并没有清空数组这么一个操作啊。。。都没有清空数组的操作如何进行第二次装东西，还是说根据面向对象的思维这个问题压根儿就不应该考虑

这看的一脸懵啊，根本看不懂  英语还不好

老师 这个editplus在哪能下？

private Demo[] demos;

(Demo... demo){
    .= }

这里面的“ Demo... ”是什么意思呀

有个疑惑,如果说普通方法中的this指的是类,而static也属于类方法,那为什么不能在static中输出this或者调用普通方法呢