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1.可能是mysql的max connections设置的问题
2.可能是多次insert,update操作没有关闭session,需要在spring里配置transaction支持。
解决:
1.修改tomcat里的session 的time-out时间减少为20,(不是必改项)
2.对处理量大的对数据库insert或update的操作提供transaction支持.
=======================================
下面的是解决办法:
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: "Too many connections"
原因:
因为你的mysql安装目录下的my.ini中设定的并发连接数太少或者系统繁忙导致连接数被占满
解决方式:
打开MYSQL安装目录打开MY.INI找到max_connections(在大约第93行)默认是100 一般设置到500~1000比较合适,重启mysql,这样1040错误就解决啦。
max_connections=1000
一定要重新启动MYSQL才能生效
CMD->
net stop mysql
net start mysql
关于改变innodb_log_file_size后无法启动mysql的问题
innodb_buffer_pool_size=768M
innodb_log_file_size=256M
innodb_log_buffer_size=8M
innodb_additional_mem_pool_size=4M
innodb_flush_log_at_trx_commit=0
innodb_thread_concurrency=20
以上是对innodb引擎的初步优化, 发现是更新innodb_log_file_size=256M时候出现了问题,只要加上这个就无法启动,
后来才知道原来要STOP服务先,然后再删除原来的文件………
打开/MySQL Server 5.5/data
删除ib_logfile0, ib_logfile1........ib_logfilen
再开启选项,成功启动。

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