B4J Question Error in mysql

[Pooya1]

Hi
My code

Username        =    "root"
    Password        =    "1234"
    Databasename    =    "db"
  
    sql1.Initialize2("com.mysql.cj.jdbc.Driver", $"jdbc:mysql://localhost/${Databasename}?characterEncoding=utf8"$,Username,Password)
    sql1.ExecNonQuery("INSERT INTO data(sMobile,sID) VALUES('123123','434')")

Tip: when i used com.mysql.jdbc.Driver,it get error that i have to replace com.mysql.jdbc.Driver with com.mysql.cj.jdbc.Driver and after replace this driver,i dont have problem about driver

While my parameter is correct and i can connect to mysql with php
But i cannot connect to mysql with B4j

I run b4j output in VPS
My database is mariadb 5.5.56-MariaDB - MariaDB Server
connector : mysql-connector-java-8.0.11.jar

Error :

main._appstart (java line: 61)
com.mysql.cj.jdbc.exceptions.CommunicationsException: 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 com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:172)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:862)
at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444)
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230)
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
at anywheresoftware.b4j.objects.SQL.Initialize2(SQL.java:56)
at b4j.example.main._appstart(main.java:61)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:90)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:77)
at b4j.example.main.main(main.java:29)
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 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.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:103)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:149)
at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:165)
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:92)
at com.mysql.cj.NativeSession.connect(NativeSession.java:152)
at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:982)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:852)
... 14 more
Caused by: java.net.ConnectException: Connection refused (Connection refused)
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:173)
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:66)
... 17 more

 

[Erel]

Make sure that the db server accepts TCP/IP connections. MySQL doesn't allow it by default.

 

[Pooya1]

Make sure that the db server accepts TCP/IP connections. MySQL doesn't allow it by default.

How do i do it? i'm beginner in b4j and server
I also bind ip to 0.0.0.0 already but not working
Thanks

 

[sorex]

you'll need to use the % wild card to allow connections from anymachine

 

[Pooya1]

Solved
Edit my.cnf file and add
port=3306
bind-address="0.0.0.0"
to file and restart service with systemctl restart mariadb/mysql

After run jar file again,maybe you see below error
error The server time zone value 'CEST' is unrecognized or represents more than one time zone

In this error please add
&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC to b4j driver query