public static void main(String[] args) {
        List<Integer> startArrs = new ArrayList<>();
        for (int i = 0; i < 5000; i++) {
            startArrs.add((int) (Math.random() * 9999 + 1));
        }
        BufferedWriter bw = null;
        BufferedReader br = null;
        try {
            //5000个随机数写入
            bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("D:\\a.txt")));
            for (Integer i : startArrs) {
                bw.write(String.valueOf(i));
                bw.newLine();
            }
            //读取随机数
            br = new BufferedReader(new InputStreamReader(new FileInputStream("D:\\a.txt")) {
            });
            //读取到的随机数集合
            List<Integer> integerList = new ArrayList<>();
            String str = null;
            while ((str=br.readLine()) != null) {
                integerList.add(Integer.parseInt(str));
            }
            //求最大值，最小值，平均值
            int max=0;
            int min=0;
            int avg=0;
            int sum=0;
            for (int i=0;i<integerList.size();i++){
                if (integerList.get(i)>max){
                    max=integerList.get(i);
                }
                if (i==0){
                    min=integerList.get(i);
                }
                if (integerList.get(i)<min){
                    min=integerList.get(i);
                }
                sum+=integerList.get(i);
            }
            System.out.println("最大值："+max);
            System.out.println("最小值："+min);
            System.out.println("平均值："+(sum/integerList.size()));

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (bw != null) {
                    bw.close();
                }
                if (br != null) {
                    br.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }