Mon Mar 27 16:22:15 GMT+08:00 2023 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" com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 1,405 milliseconds ago.  The last packet sent successfully to the server was 1,405 milliseconds ago.

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:423)

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 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:423)

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.DriverManager.getConnection(DriverManager.java:664)

at java.sql.DriverManager.getConnection(DriverManager.java:247)

at com.itbaizhan.jdbcTest.main(jdbcTest.java:15)

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

at sun.security.ssl.HandshakeContext.<init>(HandshakeContext.java:171)

at sun.security.ssl.ClientHandshakeContext.<init>(ClientHandshakeContext.java:106)

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

at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:410)

at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:389)

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

... 18 more

老师我的代码和课的一样可是运行结果是上面这些为什么啊

老师，这个问题要紧吗，我在后面加了useSSL=false也不管用

我的为什么就单显示了users这一个

不应该是1吗？

老师，我这不知道怎么错的

老师，我这个出了什么问题呀

老师，请问一下，在cmd中登录MySQL需要使用账号，密码，但是在navicat进入本地连接，就可以直接登录，不需要输入密码。想要navicat进入本地连接，也输入密码才可以，怎么设置？

查找各部门收入为部门最低的那些雇员。显示他们的名字，薪水以及部门 ID。

select  em.last_name,em.salary,em.department_id from  employees  em where  em.salary in(select min(e.salary) from employees e group by e.department_id) group by em.department_id;

这个例子逻辑不对吧

老师，我也需要安装包，v：q18079205121

这是没有链接到数据库吗

老师我这个是什么问题

PropertiesTest {
    (String[] args) IOException {
        Properties prop=Properties()InputStream is = PropertiesTest..getClassLoader().getResourceAsStream()prop.load(is)String value1 = prop.getProperty()String value2 = prop.getProperty()System..println(value1++value2)}
}

这是那儿的问题呢？

com.itbaizhanjava.sql.Connectionjava.sql.DriverManagerjava.sql.SQLExceptionJdbcTest {
    (String[] args) ClassNotFoundExceptionSQLException {
        String url=String name=String pwd=Class.()Connection connection = DriverManager.(urlnamepwd)System..println(connection)}
}

老师，这是版本问题吗？这个useSSL=false怎么加，加/吗？

老师，我已经设置name为非空约束，为什么name的值还可以为空

试了很多地方  就是改不过来 依然是乱码 不知道怎么解决