Hutool 3.9 Upd __hot__ ❲90% Full❳

Fix null pointer exception in StrUtil.blankToDefault when input is null (issue #I23K7F).

## Hutool 3.9.UPD (Midnight Edition)

: Concise filtering and transformation methods via CollUtil . Hutool 3.9 UPD

Months later, Lina was promoted. In her farewell speech, she raised a cup of coffee and said: Fix null pointer exception in StrUtil

"Update. But in our world, UPD means ."