无法连接到Google Cloud SQL

Question

I am using Google compute engine, and has authorized my VM instance to Google cloud SQL. I am using this driver com.mysql.jdbc.Driver to connect to MySQL installed in compute engine VM, but unfortunately getting the following error:

com.workfor.service.DBConnection : null
com.mysql.jdbc.exceptions.jdbc4.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 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1137)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:674)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1086)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2508)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2541)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2323)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:832)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:417)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
at java.sql.DriverManager.getConnection(DriverManager.java:571)
at java.sql.DriverManager.getConnection(DriverManager.java:215)
at com.workfor.service.DBConnection.<init>(DBConnection.java:20)
at com.workforwow.controller.FRLoginServlet.processRequest(FRLoginServlet.java:47)
at com.workfor.controller.FRLoginServlet.doPost(FRLoginServlet.java:124)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:644)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:769)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1667)
at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:176)
at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:145)
at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:92)
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:394)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1650)
at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:125)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1650)
at com.google.apphosting.runtime.jetty9.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1650)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1650)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:583)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:553)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1125)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1059)
at com.google.apphosting.vmruntime.jetty9.VmRuntimeWebAppContext.doScope(VmRuntimeWebAppContext.java:461)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:110)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
at org.eclipse.jetty.server.Server.handle(Server.java:497)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:248)
at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:610)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:539)
at java.lang.Thread.run(Thread.java:745)
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.jdbc.MysqlIO.readFully(MysqlIO.java:3161)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:598)
... 53 more

Answer 1

Are you trying to interface with the compute engine from a separate computer?

If that is the case, it seems your server isn't receiving the connection from the client.

Check the firewall client and server side, make sure none of your connections are being blocked.