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From Liqiao Han <milk...@winlab.rutgers.edu>
Subject NullPointerException @ cocoon+ mysql //thank you!
Date Sat, 28 Feb 2004 20:07:29 GMT
I have struggled with cocoon+mysql for a week and failed to make themwork!
I am new to mysql and cocoon both. now I totally have no idea what to do.

What I did:

1. I copied the "mysql-connector-java-3.0.11-stable-bin.jar" to
$COCOON_HOME/WEB-INF/lib
2. add the following to the web.xml
   <!-- For MySQL Driver: -->
        com.mysql.jdbc.Driver
3. add the following to the cocoon.xconf
  <jdbc name="YourPoolName">
    <pool-controller min="5" max="10"/>

<dburl>jdbc:mysql://boss.mylab.org:3306/tbdb?autoReconnect=true</dburl>
    <user>YourUsername</user>
    <password>YourPassword</password>
  </jdbc>

  in fact I am not quite sure the database name, user name and password
above.
   A>  the database server doesn't require an user name or password to use
the database, but it dos require an account to login in to the OS, I don't
know  how to set the user and password here?
  B> I am not sure the database name too. After I login on to the server
by
ssh, I can type
             > mysql
              >use tbdb
and then, I can inquery the table I want,
so is "tbdb"  the one I should set after the port number?

4: here is what I add to the sitemap.xmap
   <map:match pattern="allUsers">
      <map:generate src="allUsers.xml" />
      <map:transform type="sql">
        <map:parameter name="use-connection" value="YourPoolName" />
        <map:parameter name="show-nr-of-rows" value="true" />
        <map:parameter name="clob-encoding" value="UTF-8" />
  </map:transform>
    <map:serialize type="xml" />
  </map:match>
5, here is the allUsers.xml
  <?xml version="1.0" ?>
  <document>
   <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
 <query name="allUsers">
  select uid from users;
  </query>
  </execute-query>
  </document>

So I started the server and input the Url, the response is very
veryslow(about 5 minutes) and what I got an null pointer error. I looked
at the
error log, it says:
java.sql.SQLException: Failed to obtain connection. Made 5 attempts with
5000ms interval
 at
org.apache.cocoon.transformation.SQLTransformer$Query.getConnection(SQLTrans
former.java:1038)
 at
org.apache.cocoon.transformation.SQLTransformer.executeQuery(SQLTransformer.
java:326)
 at
org.apache.cocoon.transformation.SQLTransformer.endExecuteQueryElement(SQLTr
ansformer.java:493)


I used tcpdump to see the data transfer between my machine and the
server,actually the tcp messages were sent out and the server acked it.
but I doubt
if jdbc has sent out the query because according to the tcpdump the
messagecontains no data like following:

my-domainName.1234 >server-domainName.3306 S 123456:123456(0) win 6424
(mss
1460, nop,nop, sackOK) (DF)
server-domainName.3306 >my-domainName.1234 R 0:0 ack 123457 win 0

Now I totally have no idea why
Thanks for your help and time!

following is the error stack:
Failed to execute pipeline.
org.apache.cocoon.ProcessingException: Failed to execute pipeline.:
java.lang.NullPointerException 
Original Exception: java.lang.NullPointerException  at
org.apache.xml.serializer.ToStream.ensurePrefixIsDeclared(ToStream.java:2675
)          at
org.apache.xml.serializer.ToStream.startElement(ToStream.java:1777)
at
org.apache.xalan.transformer.TransformerIdentityImpl.startElement(Transforme
rIdentityImpl.java:1073)          at
org.apache.cocoon.xml.AbstractXMLPipe.startElement(AbstractXMLPipe.java:130)
at
org.apache.cocoon.xml.AbstractXMLPipe.startElement(AbstractXMLPipe.java:130)
at
org.apache.cocoon.transformation.AbstractSAXTransformer.startTransformingEle
ment(AbstractSAXTransformer.java:692)          at
org.apache.cocoon.transformation.SQLTransformer.start(SQLTransformer.java:80
1)          at
org.apache.cocoon.transformation.SQLTransformer.executeQuery(SQLTransformer.
java:340)          at
org.apache.cocoon.transformation.SQLTransformer.endExecuteQueryElement(SQLTr
ansformer.java:493)          at
org.apache.cocoon.transformation.SQLTransformer.endTransformingElement(SQLTr
ansformer.java:774)          at
org.apache.cocoon.transformation.AbstractSAXTransformer.endElement(AbstractS
AXTransformer.java:358)



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