public class A{
private B b;
}
public class B{
private int id;
}
//对于List<A> 按照B对象的id进行排序：
list.stream().sorted(Comparator.comparing(x-> x.getB().getId())).collect(Collectors.toList());
原文：https://www.cnblogs.com/shuaixiaobing/p/13156533.html