用默认的double类型做除法比较好一点。 增加 if(li>=1e6) continue;判断

import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner in  = new Scanner(System.in);
        int minusCount=0;
        int postCount=0;
        double sumPostive=0;
        while(in.hasNextInt()){
            int li = in.nextInt();
            if(li>=1e6) continue;
            if(li<0){
                ++ minusCount;
            }else {
                ++ postCount;
                sumPostive +=li;
            }
        }
        System.out.println(minusCount);
        System.out.printf("%.1f\n", sumPostive/postCount);
    }
}