China does not have 'official' close allies, especially not large ones. They are rather unique in their ideology (perhaps because of their size)? Quoting Wikipedia:
Much of current Chinese foreign policy is reportedly based on Premier Zhou Enlai's Five Principles of Peaceful Coexistence, and is also driven by the concept of "harmony without uniformity", which encourages diplomatic relations between states despite ideological differences.
A little further down it's noted that it often sides with Russia (to form a block against the Western countries):
China has a close economic and military relationship with Russia, and the two states often vote in unison in the UN Security Council.
As for the second question, China is slowly expanding their influence by investing in foreign infrastructure (the 'Belt and Road initiative' mentioned by Michael McFarlane), and many critics claim this is a form of diplomacy, trying to gain political influence in a more secretive way:
Debt trap diplomacy is used to describe a type of diplomacy based on debt carried out in the bilateral relations between countries with an often alleged negative intent. It involves one creditor country intentionally extending excessive credit to another debtor country with the alleged intention of extracting economic or political concessions from the debtor country when it becomes unable to honour its debt obligations. The conditions of the loans are often not made public, with the loaned money commonly used to pay contractors from the creditor country. Although the term applies to the lending practices of many countries, it is currently most commonly associated with the People's Republic of China. Recent use of bilateral agreements through China's Belt and Road Initiative have furthered this association, especially in relation to commodity backed loans for developing nations.
The alleged victims are poor countries (mostly in Africa, but I've even seen the term applied to Greece); they could be falling for this (alleged) 'trap' because other investors like Western countries might impose additional conditions, like human rights or environmental ones.