how to check wheather the mysql server is down or up using java code

Hi thanks for ur reply ,

can you please tell that what kind of exception i will get if the mysql server is down,

I am getting an exception called java.net.ConnectException ,

Is this the exception i will get if the mysql server is not running in the machine .

Please explain me ..

Thanks in advance.

Thanks,

Prakash

prakash.nmsp@gmail.coma at 2007-7-12 20:02:59 >

Thanks for ur updates

but now the problem is

am using code like this

catch(java.net.ConnectException e )

{

doing some process

}

but am not able to catch this exception here

instead am getting this exception under

catch(java.sql.SQLException e )

{

System.out.println(e);

}

how to catch the java.net.ConnectException

please help me

thanks in advance

thanks,

Prakash

prakash.nmsp@gmail.coma at 2007-7-12 20:02:59 >

Hi D,

Thank very much for ur updates .

see wen am trying to connect the mysql server if the server is down

then i should get the java.net.ConnectException right ? but now the problem is am not able to catch this exception if am using

catch(java.net.ConnectException e)

{

System.out.println(e);

}

i dont no why this ? am not able to catch this exception here instead

am getting java.net.connectException using this exception

catch(java.sql.SQLException e)

{

System.out.println(e)

}

the output am getting is :

java.sql.SQLEXcception :java.net.ConnectException :connection refused .

but actuall output shoud be

java.net.ConnectExceptoin: connection refused Right ?

are you getting my problem .

Main thing is I need to catch java.net.ConnectExcepton ..

please explain me ..

thanks in advance

thanks

~Prakash

prakash.nmsp@gmail.coma at 2007-7-12 20:02:59 >

Hi jayant,

Thank you very much for ur updates :

But now the problem is

now am trying to connecting to the mysql server and i want to do some process say i want to send a mail only if i get ConnectException

but if i cant catch this specific exception i cant send the email .

so please explain me how to catch that specific exception

i dont want to catch java.sql.SQLException ....

or Is there is any way to check the getting exception is ConnectException or something else in java.sql.SQLException catch block

please give me an idea ..

thanks in advance

Thanks,

Prakash

prakash.nmsp@gmail.coma at 2007-7-12 20:02:59 >

Hi Jayant,

Thanks for ur updates ..

Yes Jayant ,thats what am looking for

How to check the Exception type .

Please give me sample code or syntax to proceed more on this issue.

i want to check the ConnectException type under java.sql.SQLException

How to check it ? please provie me sample code or syntax if possible..

i tried in this way but its not working :

catch(java.sql.SQLException e)

{

if (e=="java.net.ConnectException")// getting error incompatible operation sqlexception and string ..

{

}

}

please give me an idea how to check the exception type .

thanks in advance

Thanks

Prakash

prakash.nmsp@gmail.coma at 2007-7-12 20:02:59 >

hi jschell,

I did not mean to exactly check instanceof ConnectException in the catch block (my fault of wrting like that), I was intending to suggest how it could be done. You are correct that ConnectException is not a SQLException.

Prakash,

You may need to check the SQL State and then take the proper action.

Thanks,

Jayant

jayantkdasa at 2007-7-21 22:35:39 >

Hi jschell ,

Thanks for your updates .

To Make it very clear what is my requirements is :

Now am getting this exception if mysql server is not running in my machine under this exception

catch(java.sql.SQLException e)

{

System.out.println(e.getMessage()));

}

and am getting output as :

java.sql.SQLException: java.net.ConnectException Unable to connect to any hosts due to exception: java.net.ConnectException: Connection refused: connect

** BEGIN NESTED EXCEPTION **

java.net.ConnectException

MESSAGE: Connection refused: connect

STACKTRACE:

java.net.ConnectException: Connection refused: connect

at java.net.PlainSocketImpl.socketConnect(Native Method)

at java.net.PlainSocketImpl.doConnect(Unknown Source)

at java.net.PlainSocketImpl.connectToAddress(Unknown Source)

at java.net.PlainSocketImpl.connect(Unknown Source)

at java.net.SocksSocketImpl.connect(Unknown Source)

........etc...

so its very clear am getting this exception coz of mysql server is not running in the machine.

Now can you please tell me i want to do some process like sending email .. only when i get this ConnectException

Please give me idea for that..

How to put a code for this ...

I dont want to worry about any other sql exceptions. i need to do proceess only wen i get this Connect Exception ..

how to proceed more on this issue.

Thanks in advance ..

Thanks,

~Prakash

prakash.nmsp@gmail.coma at 2007-7-21 22:35:39 >

Hi Jscell.

Thanks for ur updates.

sorry for putting more questions ..

I have tried this option in my codiNg part.

Note : mysql server is not running so i should get java.net.ConnectException

catch(java.sql.SQLException e)

{

e.getSQLState();

..

some coding here

}

i got the output as :

08S01

It gives the above value for e.getSQLState()- Is this the unique value for java.net.ConnectException.

Please update me .

one more question :

In what situations we will get this java.net.ConnectException ..

1. if mysql server is not running in the server and if we trying to connect to database we will get this exceptoin

..like that ..

wat are the other options we will get this java.net.ConnectException...

Or we will get this exception only mysql is not running . plz give me updates on this ..

Thanks in advance

ThanKs

~Prakash

prakash.nmsp@gmail.coma at 2007-7-21 22:35:39 >

> Hi Jscell,

>

> Do u have any idea on this.(see my previous reply..)

>

I have the idea that you are ignoring my suggestions and instead doing exactly what I said would not work.

The following is NOT a method of Throwable...

e.getSQLState();

Again you MUST read the java docs for Throwable.

jschella at 2007-7-21 22:35:39 >

> > coz i tried like this i got null value

> >

> > catch(java.sql.SQLException e)

> > {

> > System.out.println(e.getCause());// am getting

> > nulll value ..wat to do with this null value..

> > }

> >

>

> I too find that the getCause() method of the

> SQLException returns null in this particular

> situation.

And what exactly why is that relevant in terms of the OP?

The OP posted a specific example in reply #17. That example does in fact, by definition, have a nested exception.

The fact that your case is different has nothing to do with that.

The result will vary by database and driver.

> But jschell, is this the method to which you refer?

> I've always suspected that my code was a bad hack

> because ultimately mysql in it's discretion could

> alter the message itself,

Correct, but there is no other way.

You can only do what the database/driver/version allows.

jschella at 2007-7-21 22:35:39 >

>

> I am in fact using MySQL which is why I've posted to

> this thread. The stack trace that appears when I

> attempt to connect to MySQL when the server has not

> been started is similar to the one that appears in

> post 17, referring explicitly to a nested exception.

>

Either there is or isn't a nested exception attached to the exception that is thrown.

If there isn't then it means that the driver is attaching the nested part as text into the message itself.

jschella at 2007-7-21 22:35:39 >