MySQL DB 上的 SimpleJdbcInsert 在 executeAndReturnKey 方法后返回 BigInteger 而不是 Long

Question

I am running a simple insert query on a MySQL table with the following primary key declaration:

id BIGINT AUTO_INCREMENT NOT NULL PRIMARY KEY

They key returned is a BigInteger for some reason. What changes do I need to make for a Long value to be returned as the key?

EDIT

I'm making a mini-ORM basically and the Long type is not known at compile time since it is a class parameter ( AbstractDao<T, I> ). Essentially I need to be able to convert a Number to a Long without using anything that has long in it (Long.valueOf(), .longValue(), etc).

I do however have a Class instance that contains Long.class:

protected Class<?> idClass = ((Class<?>) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[1]);

Can that instance somehow be used to perform the casting? You cannot just cast a BigInteger to a Long, nor can you cast a String representation of BigInteger to a Long sadly. If there was a way to access valueOf() from my class object this might work?

Answer 1

executeAndReturnKey(...) returns aNumber , so call longValue() if you want the result as a long .

If your method doesn't know the exact numeric type needed by the caller, let the caller do the longValue() . Alternatively, write multiple methods, for the various return types you want to support, eg

public Number insertAndGetKey(...) {
    return ...executeAndReturnKey(...);
}
public int insertAndGetIntKey(...) {
    return insertAndGetKey(...).intValue();
}
public long insertAndGetLongKey(...) {
    return insertAndGetKey(...).longValue();
}

Answer 2

This, although extremely ugly, works like a charm:

var method = idClass.getMethod("valueOf", String.class);
var result = method.invoke(null, key.toString());

This returns something I can then typecast to (I) without issues. Please do let me know if you have a better solution to all this. The original question being about the BigInteger return type, this can probably be avoided.