Solution ~

Solution ~ -- Linux general technology-Linux technology and application information. for details, refer to the following section. SELinux is Enforcing and vsftp test is installed.
Yum-y install vsftpd
Service vsftpd restart
Chkconfig vsftpd on

Modify context value
Ll-Z/var/www/pub
-Rw-r --. root unconfined_u: object_r: user_home_t: s0 aaa
-Rw-r --. root unconfined_u: object_r: tmp_t: s0 bbb
-Rw-r --. root unconfined_u: object_r: user_tmp_t: s0 ccc
-Rw-r --. root unconfined_u: object_r: public_context_t: s0 ddd

Test results
Lftp 40.1.1.1
Lftp 40.1.1.1:/pub> ls
-Rw-r -- 1 0 0 13 Feb 23 :49 aaa
-Rw-r -- 1 0 0 7 Feb 23 15:39 ccc
-Rw-r -- 1 0 0 18 Feb 23 :40 ddd
Lftp 40.1.1.1:/pub> get aaa
Get: Access failed: 550 Failed to open file. (aaa)
Lftp 40.1.1.1:/pub> get ccc
Get: Access failed: 550 Failed to open file. (ccc)
Lftp 40.1.1.1:/pub> get ddd
18 bytes transferred

Q: Why can I access aaa and ccc without modifying the bool value ??
Why can I see user_home_t, user_tmp_t, and public_context_t, but cannot be downloaded?

Setenforce 0: if SELinux is set to Permissive, abcd can be downloaded. This indicates the SELinux problem, but it is
Why can't I see but cannot download the changed context. I checked some
SELinux information was not answered. It may be worth classification with context: Is the service context value related to the system context value?
I hope you can answer this question for me !!! Thank you.