springboot:Whitelabel Error Page，type=Internal Server Error, status=500

error in browser¶

"Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.
Mon Mar 21 12:43:37 CST 2022
There was an unexpected error (type=Internal Server Error, status=500)."

500 refers to the abnormal execution of the backend. Check the backend error message:

" Error attempting to get column 'username' from result set.  Cause: java.sql.SQLDataException: Cannot determine value type from string 'admin'
; Cannot determine value type from string 'admin'; nested exception is java.sql.SQLDataException: Cannot determine value type from string 'admin'] with root cause"

Wrong type of string before code at username.

Solution¶

private Integer username; changed to private String username; It turned out that I forgot to modify the string type when I typed the code. . .