1.事务中包含rpc请求
send amq,db commit
db操作成功之前，amq已收到消息，db not find，a sad story
2.int Integer
method param int,传递参数Integer，npe
beanCopy一int,一integer npe
3.mysql lock
for update悲观锁
set autocommit=0;
update xxx where id=1
--------
set autocommit=0; 锁等待，死锁
update xxx where id=1
4.mysql insertorupdate
no data,insert,return 1
has same data,return 1
hsa diff data,return 2
5.spring transaction
spring 事务传递，try catch并不会起作用
6.客户端发送一次请求，服务端收到多次
http
connection:
Keep-Alive,调整为close,http长连接，网络不稳定tcp重传机制