I'm trying to connect MySql and Java, but I get this error from this code.
Code:
public class ConnessioneMySql { public static void main(String[] args) throws SQLException { Connection cn; Statement st; ResultSet rs; String sql; cn = DriverManager.getConnection("jdbc:mysql://localhost:3306/TelegramBot", "root", "password"); sql = "SELECT * FROM Utente;"; try { st = cn.createStatement(); rs = st.executeQuery(sql); while (rs.next() == true) { System.out.println(rs.getString("IdUtente") + "\t" + rs.getString("CAPITALE") + "\t" + rs.getString("N_Inviti") + "\t" + rs.getString("Guadagno") + "\t" + rs.getString("DataUltimoAggiornamento")); } } catch (SQLException e) { System.out.println("errore:" + e.getMessage()); } cn.close(); } } Error:
Exception in thread "main" 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:174) at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64) at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:198) at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677) at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228) at ConnessioneMySql.main(ConnessioneMySql.java:11) 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.newInstanceWithCaller(Constructor.java:500) at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481) 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.NativeSocketConnection.connect(NativeSocketConnection.java:89) at com.mysql.cj.NativeSession.connect(NativeSession.java:144) at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:956) at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) ... 6 more Caused by: java.net.ConnectException: Connection refused: connect at java.base/sun.nio.ch.Net.connect0(Native Method) at java.base/sun.nio.ch.Net.connect(Net.java:503) at java.base/sun.nio.ch.Net.connect(Net.java:492) at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:588) at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:333) at java.base/java.net.Socket.connect(Socket.java:648) at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155) at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63) ... 9 more Process finished with exit code 1 I dont actualy use a localhost, but a vps i just replace the real addres with "localhost".
MySql is running.
MySql version:8.0.21
mysql-connector-java version:8.0.22
Maybe is a problem of firewall or something...
