Java 如何对存储为字符串的大数字数组进行排序

发布于11月01日

要对数组进行排序，我们不能使用整数(或Long)解析，因为大小非常大.

例如

String[] arr = new String[] {
        "545434548549387551787458475822", 
        "555434548549387551787458475822",
        "7485204875485114857489579847438573954738574359287485284574"
    };

我们在弦上只有不可分割的部分.

推荐答案

您可以使用Java的BigInteger类和一个定制的比较器对数组进行排序:

import java.util.Arrays;
import java.math.BigInteger;
import java.util.Comparator;

public class Main {
    public static void main(String[] args) {
        String[] arr = {
            "545434548549387551787458475822",
            "7485204875485114857489579847438573954738574359287485284574",
            "555434548549387551787458475822"
        };
        System.out.println("Before sorting:\n" + Arrays.toString(arr));
        Arrays.sort(arr, new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return new BigInteger(o1).compareTo(new BigInteger(o2));
            }
        });
        // Alternative lambda custom comparator: 
        // Arrays.sort(arr, (o1, o2) -> new BigInteger(o1).compareTo(new BigInteger(o2)));
        System.out.println("After sorting:\n" + Arrays.toString(arr));
    }
}

Output:个

Before sorting:
[545434548549387551787458475822, 7485204875485114857489579847438573954738574359287485284574, 555434548549387551787458475822]
After sorting:
[545434548549387551787458475822, 555434548549387551787458475822, 7485204875485114857489579847438573954738574359287485284574]