In the use of react router, the page url is changed, and the content is not refreshed. It needs to be manually refreshed before it will be changed. What is the problem? thank you.

in the use of react router (route is version 4.2), click the button, the page url has changed, the content does not refresh automatically, it needs to be refreshed manually before it will be changed. What is the situation, please give us your advice, thank you

here is my code

App.js code is as follows:

index.js :

Feb.28,2021

just remove the Router that wraps Link in App.js

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b380eb-e632.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b380eb-e632.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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