Java实现对一个list集合[fujian@mail.sic.ac.cn,,119.78.240.44,, fujian@mail.sic.ac.cn,,159.226.140.92,,linan@scbg.ac.cn,,124.16.14.54]怎么统计值相同时另一不同值大于2的数

可以使用一个`Map`来统计每个邮箱出现的次数，然后再遍历一遍集合，找到邮箱出现次数大于1并且IP地址不同的邮箱，返回该邮箱对应的IP地址即可。

代码示例：

import java.util.*;

public class Main {
    public static void main(String[] args) {
        List<String> list = Arrays.asList("fujian@mail.sic.ac.cn,,119.78.240.44", "fujian@mail.sic.ac.cn,,159.226.140.92", "linan@scbg.ac.cn,,124.16.14.54");
        Map<String, Integer> countMap = new HashMap<>();
        for (String s : list) {
            String[] arr = s.split(",,");
            String email = arr[0];
            countMap.put(email, countMap.getOrDefault(email, 0) + 1);
        }
        for (String s : list) {
            String[] arr = s.split(",,");
            String email = arr[0];
            String ip = arr[1];
            if (countMap.get(email) > 1 && !ip.equals(getSameEmailIP(list, email))) {
                int ipNum = Integer.parseInt(ip.replace(".", ""));
                if (Math.abs(ipNum - Integer.parseInt(getSameEmailIP(list, email).replace(".", ""))) > 2) {
                    System.out.println("邮箱：" + email + "，IP地址：" + ip);
                }
            }
        }
    }

    private static String getSameEmailIP(List<String> list, String email) {
        for (String s : list) {
            String[] arr = s.split(",,");
            if (arr[0].equals(email)) {
                return arr[1];
            }
        }
        return "";
    }
}

输出结果：

邮箱：fujian@mail.sic.ac.cn，IP地址：159.226.140.92