Tomcat6 can't connect to MySql (The driver has not received any packets from the server)
- by Tobias Wiesenthal
Hi all,
i'm running an Apache Tomcat 6.0.20 / MySQL 5.1.37-lubuntu / sun-java6-jdk /sun-java6-jre / sun-java6-bin on my local machine using Ubuntu 9.10 as OS.
I'm trying to get a simple DB-query example running for 2 days now, but i still get this Exception:
org.apache.jasper.JasperException: javax.servlet.ServletException: javax.servlet.jsp.JspException: Unable to get connection, DataSource invalid: "org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (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.)"
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:522)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:398)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause
javax.servlet.ServletException: javax.servlet.jsp.JspException: Unable to get connection, DataSource invalid: "org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (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.)"
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:862)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:791)
org.apache.jsp.index_jsp._jspService(index_jsp.java:104)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause
javax.servlet.jsp.JspException: Unable to get connection, DataSource invalid: "org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (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.)"
org.apache.taglibs.standard.tag.common.sql.QueryTagSupport.getConnection(QueryTagSupport.java:285)
org.apache.taglibs.standard.tag.common.sql.QueryTagSupport.doStartTag(QueryTagSupport.java:168)
org.apache.jsp.index_jsp._jspx_meth_sql_005fquery_005f0(index_jsp.java:274)
org.apache.jsp.index_jsp._jspx_meth_c_005fotherwise_005f0(index_jsp.java:216)
org.apache.jsp.index_jsp._jspx_meth_c_005fchoose_005f0(index_jsp.java:130)
org.apache.jsp.index_jsp._jspService(index_jsp.java:93)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
my web.xml looks like this :
<?xml version="1.0" encoding="utf-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/testDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
the context.xml looks like this :
<?xml version="1.0" encoding="UTF-8"?>
<Context path="/my1stApp" docBase="/var/www/jsp/my1stApp" debug="5" reloadable="true" crossContext="true">
<Resource name="jdbc/testDB" auth="Container" type="javax.sql.DataSource"
maxActive="5" maxIdle="5" maxWait="10000"
username="user" password="password" driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/some"/>
</Context>
and the jsp file looks like this:
<%@ page contentType="text/html" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%@ taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql" %>
<html>
<head>
<title>DroneLootTool</title>
</head>
<body bgcolor="white">
<sql:query var="res" dataSource="jdbc/testDB">
select name, othername
from mytable
</sql:query>
<h2>Results</h2>
<c:forEach var="row" items="${res.rows}">
Name ${row.name}<br/>
MoreName ${row.othername}<br/><br/>
</c:forEach>
</body>
</html>
read lots of forum entries / tried lots of different settings (always changed back to original settings when it didnt' work)
set TOMCAT6_SECURITY=no in /etc/default/tomcat6 because TOMCAT6_SECURITY=yes was causing trouble too
the skip-networking flag is not set for the DB (BIND 127.0.0.1 is set)
firewall is swiched off (sudo ufw disable)
MySQL works (tested several times with user used in this skript)
telnet localhost 3306 says
Trying ::1...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Connection closed by foreign host.
The TestConnection.java produced the following output:
me@my-laptop:~/Desktop$ java -classpath '/usr/share/java/mysql.jar:./' TestConnection com.mysql.jdbc.Driver jdbc:mysql://localhost:3306/testDB myuser mypassword
com.mysql.jdbc.CommunicationsException: Communications link failure
Last packet sent to the server was 0 ms ago.
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1070)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2103)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:718)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:298)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:282)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at TestConnection.checkConnection(TestConnection.java:40)
at TestConnection.main(TestConnection.java:21)
Caused by: com.mysql.jdbc.CommunicationsException: Communications link failure
Last packet sent to the server was 0 ms ago.
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1070)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:666)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1069)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2031)
... 7 more
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:2431)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:590)
... 9 more
Connection failed.
i don't know if there is a difference between the way the java driver connects to the DB and the Perl DBI module does, but this PERL skript works
#!/usr/bin/perl -w
use CGI;
use DBI;
use strict;
print CGI::header();
my $dbh = DBI->connect("dbi:mysql:some:localhost", "user", "password");
my $sSql = "SELECT * from mytable";
my $ppl = $dbh->selectall_arrayref( $sSql );
foreach my $pl (@$ppl)
{
my @array = @$pl;
print @array;
}
$dbh->disconnect;
enabled --log-warnings on the mysql, but i didn't get any new warnings.
When i was searching the logs for warnings i found this messages when i restart the tomcat, don't know if it helps to find the problem :
Feb 2 19:50:37 tobias-laptop jsvc.exec[3129]: 02.02.2010 19:50:37 org.apache.catalina.startup.HostConfig checkResources#012INFO: Undeploying context [/myapp]
Feb 2 19:50:37 tobias-laptop jsvc.exec[3129]: 02.02.2010 19:50:37 org.apache.catalina.loader.WebappClassLoader clearReferencesThreads#012SCHWERWIEGEND: A web application appears to have started a thread named [MySQL Statement Cancellation Timer] but has failed to stop it. This is very likely to create a memory leak.
Feb 2 19:50:37 tobias-laptop jsvc.exec[3129]: 02.02.2010 19:50:37 org.apache.catalina.startup.HostConfig deployDescriptor#012INFO: Deploying configuration descriptor myapp.xml
