message from server: “Host ‘xxxxxx‘ is blocked because of many connection errors； unblock with ‘m

Problem description

Caused by: com.mysql.cj.exceptions.CJException: null,  
message from server: "Host 'xxx.xxx.xxx.xxx' is blocked 
because of many connection errors; 
unblock with 'mysqladmin flush-hosts'"

Problem analysis

An error message indicates a phenomenon ：

Messages from the server ：“ host ‘xxxx’ Blocked due to many connection errors ;
Use ‘mysqladmin flush hosts’ Unblock ”.

The reason why I have this problem here ：
Connection access is not set MySQL Database account and password information , After starting the project , Keep reconnecting , Lead to MySQL Blocked due to multiple connection errors .

According to the description in the error message , Use flush hosts Conduct Block release .

Problem solving

• 1、 If there is no connection account and password information , Create accounts and passwords .

  create user test_user@'%' identified by '[email protected]';
  grant all privileges on test.* to test_user@'%' with grant option;
  flush privileges;
  

• 2、 Log in to the database

  mysql -u xxxx -p
   If it's a remote connection , Then take the following command 
  mysql -hXXXX -u xxxx -p
  

• 3、 After logging in , stay mysql In the implementation of flush hosts.
• 4、 Restart project , Observe the project startup log information .