Connect timed out of database connection

The requirement is to write a script , I just wanted to write jar Bag lost linux It's OK to execute in .jar It's local windows The execution in the environment is normal , Throw it to linux Let's say the connection timed out , There must be no problem with the database account and password , After doing this for a long time, I still don't know what the problem is . Jomi

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Take the answer ：

1、 Under confirmation linux Whether the firewall is shielded
2、linux Server to mysql Whether there are network devices between them , Whether the network device is configured correctly
3、telnet mysql The port of , See if it works
4、 have a look mysql Whether the corresponding port on the server normally provides external services

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