linux下程序JDBC鏈接不到mysql數據庫

　　今天在linux下部署一個 JavaEE項目的時候老是鏈接不到Mysql數據庫，檢查以後發現鏈接池的配置肯定是對的，進入linux服務器以後以mysql -uname -ppassword鏈接老是報Access denied for user 'root'@'localhost' (using password: YES」)，最終解決掉這個問題以後仍是鏈接不上(參考:http://www.cnblogs.com/qlqwjy/p/8315802.html)。

 

　　解決掉以後經過在本地的sqlyog鏈接都報錯，但是在linux服務器上能夠運行，用下面語句受權以後仍是鏈接不上，而且Java程序也是鏈接不上

受權:

mysql> grant all privileges on *.* to 'root'@'%' identified by 'admin'; mysql> grant all privileges on *.* to 'root'@'localhost' identified by 'admin'; mysql> flush privileges;

 

 查看登陸用戶信息:

mysql> select user,host,password  from mysql.user;

 

 

 此時用service myqld stop發現不起做用，也就是關不掉mysql服務，用service mysqld start啓動報錯:

Starting mysqld (via systemctl):  Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details.

 

 

最終經過查看mysql的錯誤日誌發現mysql服務一直開啓着:

mysql> show variables like 'error_log'; Empty set (0.00 sec) mysql> show variables like 'log_error'; +---------------+---------------------+
| Variable_name | Value               |
+---------------+---------------------+
| log_error     | /var/log/mysqld.log |
+---------------+---------------------+
1 row in set (0.00 sec) mysql> quit Bye [root@iz2ze46xi6pjjj69ailg9lz logs]# cat /var/log/mysqld.log

 

錯誤日誌:

180119 10:01:35 mysqld_safe Logging to '/var/log/mysqld.log'. 180119 10:01:35 mysqld_safe A mysqld process already exists
180119 10:01:37 mysqld_safe Logging to '/var/log/mysqld.log'. 180119 10:01:37 mysqld_safe A mysqld process already exists
180119 10:01:38 mysqld_safe Logging to '/var/log/mysqld.log'. 180119 10:01:38 mysqld_safe A mysqld process already exists

 

 

 

 

 解決辦法:最後是經過查看mysql相關的pid而後殺死進程以後從新啓動mysql解決的:

[root@iz2ze46xi6pjjj69ailg9lz logs]# ps -ef|grep mysql mysql 24359     1  0 10:31 ?        00:00:00 /bin/sh /usr/bin/mysqld_safe --basedir=/usr
mysql    24541 24359  0 10:31 ?        00:00:01 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --log-error=/var/log/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid --socket=/var/lib/mysql/mysql.sock
root     25420 25023  0 11:17 pts/2    00:00:00 grep --color=auto mysql
[root@iz2ze46xi6pjjj69ailg9lz logs]# kill -9 24541
[root@iz2ze46xi6pjjj69ailg9lz logs]# kill -9 24359

 

 經過上面命令查看到mysql相關的進程id以後殺掉進程，重啓mysql服務發現一切正常。

[root@iz2ze46xi6pjjj69ailg9lz logs]# service mysqld start