The following error occurred when opening mysql of xampp today

2017-07-26 07:35:04 11048 [Note] Plugin 'FEDERATED' is disabled.
2017-07-26 07:35:04 2874 InnoDB: Warning: Using innodb_additional_mem_pool_size is DEPRECATED. This option may be removed in future releases, together with the option innodb_use_sys_malloc and with the InnoDB's internal memory allocator.
2017-07-26 07:35:04 11048 [Note] InnoDB: The InnoDB memory heap is disabled
2017-07-26 07:35:04 11048 [Note] InnoDB: Mutexes and rw_locks use Windows interlocked functions
2017-07-26 07:35:04 11048 [Note] InnoDB: Compressed tables use zlib 1.2.3
2017-07-26 07:35:04 11048 [Note] InnoDB: Not using CPU crc32 instructions
2017-07-26 07:35:04 11048 [Note] InnoDB: Initializing buffer pool, size = 16.0M
2017-07-26 07:35:04 11048 [Note] InnoDB: Completed initialization of buffer pool
2017-07-26 07:35:04 11048 [Note] InnoDB: Highest supported file format is Barracuda.
2017-07-26 07:35:04 11048 [Note] InnoDB: The log sequence numbers 0 and 0 in ibdata files do not match the log sequence number 1735445 in the ib_logfiles!
2017-07-26 07:35:04 11048 [Note] InnoDB: Database was not shutdown normally!
2017-07-26 07:35:04 11048 [Note] InnoDB: Starting crash recovery.
2017-07-26 07:35:04 11048 [Note] InnoDB: Reading tablespace information from the .ibd files...
2017-07-26 07:35:04 11048 [ERROR] InnoDB: Attempted to open a previously opened tablespace. Previous tablespace how2java/category_ uses space ID: 1 at filepath: .\how2java\category_.ibd. Cannot open tablespace mysql/innodb_table_stats which uses space ID: 1 at filepath: .\mysql\innodb_table_stats.ibd
InnoDB: Error: could not open single-table tablespace file .\mysql\innodb_table_stats.ibd
InnoDB: We do not continue the crash recovery, because the table may become
InnoDB: corrupt if we cannot apply the log records in the InnoDB log to it.
InnoDB: To fix the problem and start mysqld:
InnoDB: 1) If there is a permission problem in the file and mysqld cannot
InnoDB: open the file, you should modify the permissions.
InnoDB: 2) If the table is not needed, or you can restore it from a backup,
InnoDB: then you can remove the .ibd file, and InnoDB will do a normal
InnoDB: crash recovery and ignore that table.
InnoDB: 3) If the file system or the disk is broken, and you cannot remove
InnoDB: the .ibd file, you can set innodb_force_recovery > 0 in my.cnf
InnoDB: and force InnoDB to continue crash recovery here.

One of the lines has an error, and then the following is a detailed explanation of what the solution is, that is, this line:

InnoDB: Error: could not open single-table tablespace file .\mysql\innodb_table_stats.ibd

This error can be done according to the solution, and then
https://stackoverflow.com/questions/19211817/mysql-not-launching-on-xampp
Others translated it and explained how to do it.
But it's not very useful. It's found to be useful in the last reply, that is.
exit Xampp server go to your C:\xampp\mysql\data directory delete the ibdata1 file restart xampp server It should work
Exit xampp, delete the D: xampp mysql data ibdata1 file, and restart xampp.