How to properly connect to MySql database using Java (JDBC)?

Question

MySQL

I'm trying to connect to a database.

String URL = "jdbc:mysql://localhost:3306/schema";
        String UserName = "root";
        String Password = "1234";
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection connection = DriverManager.getConnection(URL, UserName, Password);
            Statement statement = connection.createStatement();
            //ResultSet resultSet = statement.executeQuery("SELECT * FROM maps");
            //while (resultSet.next()) {
            //    System.out.println(resultSet.getString(1));
            //}
            //resultSet.close();
            statement.close();
            connection.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

Gives an error message:

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Client does not support authentication protocol requested by server; consider upgrading MySQL client
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:488)
at com.mysql.jdbc.Util.handleNewInstance(Util.java: 406)
at com.mysql.jdbc.Util.getInstance(Util.java:381)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:984)
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423 )
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:910)
at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:3923)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java: 1273)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2031)
at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:718)
at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:46 )
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
) .reflect.Constructor.newInstance(Constructor.java:488)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:302)
at com. mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:282)
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java: 228)
at com.maps.Main.process(Main.java:34)
at com.maps.Main.doGet(Main.java:20)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter. doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache .catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke
(AuthenticatorBase.java:493)
(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
at org.apache. catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java: 800)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol
$ConnectionHandler.process(AbstractProtocol.java:800)
.doRun(NioEndpoint.java:1471)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135 )
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java. base/java.lang.Thread.run(Thread.java:844)

Connection line error. How to connect to the database?

Answer 1

Client does not support authentication protocol requested by server; consider upgrading MySQL client

Something is not clear in the message? Update the client library.
If we are talking about mysql 8.0, then the second opportunity is to change the default-authentication-plugin , which was changed in 8.0.

Answer 2

The string is not needed since Java 6 - now the JDBC driver is searched and loaded using SPI technology Class.forName("com.mysql.jdbc.Driver");