Hi,
I know that if a MySQL database connection is instantiated in the
constructor of a Spout or Bolt, it won't work. It should be instantiated in
open() or prepare().
Problem is, when I store this database connection as a member of a class
which is a member of a bolt. Eg:
*public class MongoIteratorBolt extends BaseRichBolt { private S1Table
s1;} public class S1Table implements Serializable { private
Connection connRef; private Statement stmt; private ResultSet rs;
public S1Table(Connection conn, final String tableName) {
try { this.connRef = conn; this.stmt =
conn.createStatement(); *
I get an error like this:
* 8811 [main] ERROR o.a.s.s.o.a.z.s.NIOServerCnxnFactory - Thread
Thread[main,5,main] diedjava.lang.IllegalStateException: Bolt 'mongoBolt'
contains a non-serializable field of type
com.mysql.jdbc.SingleByteCharsetConverter, which was instantiated prior to
topology creation. com.mysql.jdbc.SingleByteCharsetConverter should be
instantiated within the prepare method of 'mongoBolt at the earliest. at
org.apache.storm.topology.TopologyBuilder.createTopology(TopologyBuilder.java:127)
~[MyStorm.jar:?] at com.slh.Mystorm.MyStorm.main(MyStorm.java:76)
~[MyStorm.jar:?]Caused by: java.lang.RuntimeException:
java.io.NotSerializableException:
com.mysql.jdbc.SingleByteCharsetConverter at
org.apache.storm.utils.Utils.javaSerialize(Utils.java:167)
~[MyStorm.jar:?] at
org.apache.storm.topology.TopologyBuilder.createTopology(TopologyBuilder.java:122)
~[MyStorm.jar:?] ... 1 moreCaused by: java.io.NotSerializableException:
com.mysql.jdbc.SingleByteCharsetConverter at
java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184)
~[?:1.8.0_73]*
I assume it is because of one of these which aren't getting serialized:
* private Connection connRef; private Statement stmt; private
ResultSet rs; *
So if you can't declare them as class members because they don't get
serialized, then how do you declare them so that the entire class will have
access to it and I won't have to keep creating new connections for every
query?
I'm quite sure that declaring and initializing them in *prepare()* won't
ensure that the rest of the class functions would be able to access it.
--
Regards,
Navin
