I have written a JPA attribute converter to convert values between java.lang.String
and java.nio.Path
.
The converter works fine for non-null value. In case of converting null
from the Java world to SQL, Hibernate inserts the string value null
into the database row. But I would to have (SQL) NULL
, so that the column is either empty or in case of NOT NULL contraint a constraint violation will be caused.
What do I wrong?
The converter looks like this:
@Converter
public class PathConverter
implements AttributeConverter<Path, String> {
@Override
public String convertToDatabaseColumn(Path path) {
return Objects.toString(path);
}
@Override
public Path convertToEntityAttribute(String columnValue) {
return Optional.ofNullable(columnValue)
.map(Paths::get).orElse(null);
}
}
I am using Spring Boot 2.7.1 with Hibernate for my application.
CodePudding user response:
Change:
public String convertToDatabaseColumn(Path path) {
return Objects.toString(path);
}
To:
public String convertToDatabaseColumn(Path path) {
return path == null ? null : Objects.toString(path);
}
because Objects.toString()
return the string "null" if the value is null
From the documentation:
Returns the result of calling toString for a non-null argument and "null" for a null argument.