老师,这个选什么呀
老师,是不是没有注册root这个用户,还是权限没开
为什么没有任何反应呢老师。
啊,有个疑问啊老师,咱properties文件里不是只给到数据库名,他咋知道操作哪个表
为社么要在外面定义一个空Connection
不直接在里面定义
这是什么意思啊
老师 没有注册激活 可以一直使用吗
这个查询用and只能查询一条数据 不能查询多条
varchar后面的长度是指的多少空间,或者说一个长度是指一个字符或者字节,还是等于一个字
续7楼问题,解决了该bug后,又出现新的
代码 grant select on sxt.a123 to 'u_sxt'@ with grant option;
报错 1410 - You are not allowed to create a user with GRANT
老师这个注册码用不了怎么办啊
老师我这个是什么问题为啥链接失败 Tue Nov 07 04:20:51 CST 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 782 milliseconds ago. The last packet sent successfully to the server was 774 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 jdbcTest.main(jdbcTest.java:22) 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:101) at sun.security.ssl.TransportContext.kickstart(TransportContext.java:238) at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:394) at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:373) at com.mysql.jdbc.ExportControlled.transformSocketToSSLSocket(ExportControlled.java:186) ... 18 more
有没有一章是专门讲这些部分名称的 根本分不清哪个是哪个 看的云里雾里的
直接写关闭ResultSet、Statement、Connection,前面的关闭Connection和Statement方法可以不再写吗?
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