SelectUtils buildSelectFromTableAndExpressions not contain where clause ？

My needs are as follows
1. before
```sql
select * from  tablename where id = 18 and name='$null$'
```
2. Handling by JSqlParser
```java
some code like
if where clause contians `$null$` value, remove this where expression
```
3. after 
```sql
select * from  tablename where id = 18
```
please help，Thank you very much。