MySQL访问被拒绝JDBC

Question

I am using jdbc and Tomcat server. It has been running perfectly for a week, and It suddenly broken down. I also noticed that I don't even need a password to login mysql from command line. Here is my code:

 Class.forName("com.mysql.jdbc.Driver").newInstance();
    Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/larryxu","root","");

Here is the stack trace at catalina.out:

    Fri Nov 10 08:20:32 UTC 2017 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.
java.sql.SQLException: Access denied for user 'root'@'localhost'
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:873)
        at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1710)
        at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1226)
        at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2205)
        at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2236)
        at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2035)
        at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:790)
        at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
        at sun.reflect.GeneratedConstructorAccessor12.newInstance(Unknown Source)
        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:400)
        at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
        at java.sql.DriverManager.getConnection(DriverManager.java:664)
        at java.sql.DriverManager.getConnection(DriverManager.java:247)
        at larryxu.MainServlet.recordVisitor(MainServlet.java:88)
        at larryxu.MainServlet.doPost(MainServlet.java:49)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
        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:53)
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:199)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:475)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
        at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:651)
        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:500)
        at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
        at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:754)
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1376)
        at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(Thread.java:748)

Answer 1

Make sure that the provided credentials are correct.

you can also try like this

String url="jdbc:mysql://localhost:3306/larryxu";
String userName="root"
String password=""
try{

    Class.forName("com.mysql.jdbc.Driver").newInstance();

    Connection con=DriverManager.getConnection(url,username,password);
...
}

even if it did not work then you have to give PRIVILEGES

click here for granting privileges