I’m using a servlet to try to connect to a mysql database on my website, but it always says that it timed out and that there is a communications link failure.<\/p>\n
final String DB_URL = \"jdbc:mysql:\/\/blah.org\/blah_DbName\";\nconn = DriverManager.getConnection(DB_URL, USER, PASS);\n<\/code><\/pre>\nThat is what I am using to connect, but it’s not working. Is my url properly created? Also, I do not know the root password, so I added a user to the database and I am using that users username and password to connect, so is there a way to get the root password.<\/p>\n
Also, some people say that the port number is required in the url, but where do I find the port number? My hosting provider is hostmantis.<\/p>\n
Stack Trace<\/p>\n
Feb 19, 2013 12:15:11 AM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc\nSEVERE: The web application [\/servlettest] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.\nFeb 19, 2013 12:15:11 AM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads\nSEVERE: The web application [\/servlettest] is still processing a request that has yet to finish. This is very likely to create a memory leak. You can control the time allowed for requests to finish by using the unloadDelay attribute of the standard Context implementation.\nFeb 19, 2013 12:15:12 AM org.apache.catalina.core.StandardContext reload\nINFO: Reloading Context with name [\/servlettest] is completed\n<\/code><\/pre>\ncom.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure\n\n\nThe last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.\n at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)\n at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)\n at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)\n at java.lang.reflect.Constructor.newInstance(Unknown Source)\n at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)\n at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1117)\n at com.mysql.jdbc.MysqlIO.(MysqlIO.java:355)\n at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2461)\n at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2498)\n at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2283)\n at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:822)\n at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:47)\n at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)\n at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)\n at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)\n at java.lang.reflect.Constructor.newInstance(Unknown Source)\n at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)\n at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:404)\n at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:317)\n at java.sql.DriverManager.getConnection(Unknown Source)\n at java.sql.DriverManager.getConnection(Unknown Source)\n at servlets.DatabaseAccess.doGet(DatabaseAccess.java:59)\n at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)\n at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)\n at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:306)\n at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)\n at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)\n at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)\n at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)\n at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)\n at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)\n at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:380)\n at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)\n at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)\n at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)\n at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:288)\n at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)\n at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)\n at java.lang.Thread.run(Unknown Source)\nCaused by: java.net.ConnectException: Connection timed out: connect\n at java.net.DualStackPlainSocketImpl.connect0(Native Method)\n at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)\n at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)\n at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)\n at java.net.AbstractPlainSocketImpl.connect(Unknown Source)\n at java.net.PlainSocketImpl.connect(Unknown Source)\n at java.net.SocksSocketImpl.connect(Unknown Source)\n at java.net.Socket.connect(Unknown Source)\n at java.net.Socket.connect(Unknown Source)\n at java.net.Socket.(Unknown Source)\n at java.net.Socket.(Unknown Source)\n at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:259)\n at com.mysql.jdbc.MysqlIO.(MysqlIO.java:305)\n ... 32 more\n<\/code><\/pre>\n\n- \n
Communications link failure<\/code><\/p>\nIt clearly says that you are behind a proxy or you doesn’t have internet connection.<\/p>\n
configure proxy using -httpProxyHost<\/code> jvm runtime parameter if you are behind proxy<\/p>\n<\/li>\n<\/ol>\nOriginally posted 2014-02-04 12:03:46. <\/small><\/p>","protected":false},"excerpt":{"rendered":"
I’m using a servlet to try to connect to a mysql database on my website, but it always says that it timed out and that there is a communications link failure. final String DB_URL = “jdbc:mysql:\/\/blah.org\/blah_DbName”; conn = DriverManager.getConnection(DB_URL, USER, PASS); That is what I am using to connect, but it’s not working. Is my […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2641","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/2641","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/comments?post=2641"}],"version-history":[{"count":0,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/2641\/revisions"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=2641"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=2641"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=2641"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}