java - MySQL J 连接器

Question

您可以通过 IntelliJ idea 帮助使用 J Connector 吗？我只是使用以下代码:

    String connectionString = "jdbc:mysql://127.0.0.1:33060/";
    Connection connection = DriverManager.getConnection(connectionString,"root","****");

我得到以下异常:

线程“main”中出现异常

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

最后一次成功发送到服务器的数据包是在 0 毫秒前。

The driver has not received any packets from the server.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:207)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
    at testLab.Main.main(Main.java:9)
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
    at com.mysql.cj.protocol.a.NativeProtocol.readMessage(NativeProtocol.java:555)
    at com.mysql.cj.protocol.a.NativeProtocol.readServerCapabilities(NativeProtocol.java:507)
    at com.mysql.cj.protocol.a.NativeProtocol.beforeHandshake(NativeProtocol.java:397)
    at com.mysql.cj.protocol.a.NativeProtocol.connect(NativeProtocol.java:1440)
    at com.mysql.cj.NativeSession.connect(NativeSession.java:165)
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:955)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
    ... 6 more
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
    at com.mysql.cj.protocol.FullReadInputStream.readFully(FullReadInputStream.java:67)
    at com.mysql.cj.protocol.a.SimplePacketReader.readHeader(SimplePacketReader.java:63)
    at com.mysql.cj.protocol.a.SimplePacketReader.readHeader(SimplePacketReader.java:45)
    at com.mysql.cj.protocol.a.NativeProtocol.readMessage(NativeProtocol.java:549)
    ... 12 more

If I connect through MS Visual Studio through .NET connector everything is successful. If I change anything in the port I receive the exception below having in mind I check the MySQL DB Timezone and it is in my TZ:
Exception in thread "main" java.sql.SQLException: The server time zone value '' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:207)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
    at testLab.Main.main(Main.java:9)
Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85)
    at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132)
    at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2234)
    at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2258)
    at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1319)
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:966)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
    ... 6 more

Answer 1

所以我的问题似乎是众所周知的时区。正如您在使用端口 3306 时的异常中看到的，时区值为空:线程“main”中出现异常 java.sql.SQLException:服务器时区值 '' 无法识别或代表多个时区。如果您想利用时区支持，则必须配置服务器或 JDBC 驱动程序(通过 serverTimezone 配置属性)以使用更具体的时区值。

当然，MySQL 服务器已将时区设置为系统，因此时间是正确的。将 MySQL 时区更改为 +02:00 没有任何区别，异常仍然显示空值。

现在对于每个连接，我必须在连接字符串中使用以下部分: ?serverTimezone=UTC

如果有人能给我建议如何直接在连接器上更改它，这样我就不必在每个项目中编写它，我将不胜感激。