how to catch connection refused exception ?

[go canal]

hi,

would like to catch connection exception, for example, if mongo is not started but we want to open a database,

I saw the exception:

java.io.IOException: couldn't connect to [/127.0.0.1:27017] bc:java.net.ConnectException: Connection refused: connect

but not able to catch it. 

try {

mongo = new Mongo (mongo_host, Integer.parseInt(mongo_port));

// get a lis of databases

List<String> dbs = mongo.getDatabaseNames();

} catch (NumberFormatException e) {

logger.error("port is not a valid number");

System.exit(1);

} catch (UnknownHostException e) {

logger.error(e.getMessage());

System.exit(1);

} catch (MongoException.Network e) {

logger.error(e.getMessage());

System.exit(1);

} 

the exception happened when trying to get the list of databases. But it is not captured by the exceptions I used. So wondering which one I should add?

 

thanks,
canal

[Scott Hernandez]

java.io.IOException

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[go canal]

no, it does not catch the exception, I have no idea why.

 

thanks,
canal

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[go canal]

traced the Java driver source code, the error is thrown by fetchMaxBsonObjectSize() in the DBTCPConnector.java

    int fetchMaxBsonObjectSize() {

        if (_masterPortPool == null)

            return 0;

        DBPort port = _masterPortPool.get();

        try {

            CommandResult res = port.runCommand(_mongo.getDB("admin"), new BasicDBObject("isMaster", 1));

            // max size was added in 1.8

            if (res.containsField("maxBsonObjectSize")) {

                maxBsonObjectSize = ((Integer) res.get("maxBsonObjectSize")).intValue();

            } else {

                maxBsonObjectSize = Bytes.MAX_OBJECT_SIZE;

            }

        } catch (Exception e) {

            _logger.log(Level.WARNING, "Exception determining maxBSON size using"+maxBsonObjectSize, e);

        } finally {

            port.getPool().done(port);

        }

        return maxBsonObjectSize;

    }

later it throw MongoException.Network

 

thanks,
canal

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From: go canal <goc...@yahoo.com>
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Sent: Monday, September 26, 2011 2:10 PM

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