I am trying to generate some coins with the client ./bitcoin-qt -testnet -gen How can I config to what address the money go ?
p.s.: actually I got notification for mining success but no coins in the wallet.
It is possible that you found a block, but it got orphaned. Another miner may have found a block around the same time, and for whatever reason, the next miner to find a block chose to link to theirs instead of yours.
This happens a lot on testnet because of a special rule that if no block is found for 20 minutes, the difficulty drops temporarily to 1. When this happens, typically lots of people find blocks right away, and it's a toss up which one is used by the next miner.
You could inspect debug.log if you want to know exactly what happened.
The address is created in the wallet that is controlled by bitcoin-qt, so it will eventually pop up in your transactions, but the coins take time to mature. This is a security precaution to avoid transactions that spend coins from a block that will later be replaced. Using the Bitcoin JSON-RPC might show them already even if they have not matured yet:
./bitcoin-qt -testnet listunspent 0
should list all unspent transaction outputs with at least 0 confirmations, i.e., everything. One of them should be your reward. From the output you can deduce the generating transaction's Hash and from there you can simply use
./bitcoin-qt -testnet gettransaction <txid> to get details about the transaction.