Spring中如何使用Comparator接口

List<Integer> intList = Arrays.asList(2, 3, 1);
Collections.sort(intList, (o1, o2) -> {
   return o2-o1;
});

public class Emp {
   private int empNo;
   private String eName;
   //省略getter setter
   @Override
   public String toString()
   {
      return "empno:\t"+empno+"\tename:\t"+ename;
   }
}
Comparator<Emp> comparator = (o1, o2) -> {
            return o1.getEmpno()-o2.getEmpno();
};
empList.sort(comparator);

@Override
public int compare(@Nullable Object o1, @Nullable Object o2) {
   return doCompare(o1, o2, null);
}
private int doCompare(@Nullable Object o1, @Nullable Object o2, @Nullable OrderSourceProvider sourceProvider) {
   //判断是否实现了PriorityOrdered接口
    //o1为原先的后一个元素
    //o2为原先的前一个元素
   boolean p1 = (o1 instanceof PriorityOrdered);
   boolean p2 = (o2 instanceof PriorityOrdered);
  //p1实现了PriorityOrdered，但是p2没实现PriorityOrdered，则p1优先级更高
   if (p1 && !p2) {
         ////小于0 表示逆序 o1排前
      return -1;
   }
   else if (p2 && !p1) {
     //p2实现了PriorityOrdered，但是p1没实现PriorityOrdered，则p2优先级更高
            //大于0 表示正序 o2排前
      return 1;
   }
   int i1 = getOrder(o1, sourceProvider);
   int i2 = getOrder(o2, sourceProvider);
   return Integer.compare(i1, i2);
}
 
    protected int getOrder(@Nullable Object obj) {
        if (obj != null) {
            Integer order = findOrder(obj);
            if (order != null) {
                return order;
            }
        }
    //Integer.MAX_VALUE代表最低优先级
        return Ordered.LOWEST_PRECEDENCE;
    }
 
    @Nullable
    protected Integer findOrder(Object obj) {
        return (obj instanceof Ordered ? ((Ordered) obj).getOrder() : null);
    }

@Override
@Nullable
protected Integer findOrder(Object obj) {
   // Check for regular Ordered interface
   //检查常规的Order接口
   Integer order = super.findOrder(obj);
   if (order != null) {
      return order;
   }
     //检查@Order注解和@Priority注解
   // Check for @Order and @Priority on various kinds of elements
   if (obj instanceof Class) {
      return OrderUtils.getOrder((Class<?>) obj);
   }
   else if (obj instanceof Method) {
      Order ann = AnnotationUtils.findAnnotation((Method) obj, Order.class);
      if (ann != null) {
         return ann.value();
      }
   }
   else if (obj instanceof AnnotatedElement) {
      //AnnotatedElement代表在当前运行的java虚拟机中一个可以被注解的元素，这个接口允许通过反射读取元素上面的注解，这与我们之                前的理解是一致的
      //https://www.yuque.com/cuihualong/javaseries/sh91es
      Order ann = AnnotationUtils.getAnnotation((AnnotatedElement) obj, Order.class);
      if (ann != null) {
         return ann.value();
      }
   }
   else {
      order = OrderUtils.getOrder(obj.getClass());
      if (order == null && obj instanceof DecoratingProxy) {
         order = OrderUtils.getOrder(((DecoratingProxy) obj).getDecoratedClass());
      }
   }
   return order;
}