正規表現を使用して IP を並べ替える方法を説明します

package IPSort;
import java.util.Arrays;
/**
 * 利用正则表达对IP进行排序,分四步
 * @author tiger
 *
 */
public class IPSortTest {
 public static void main(String[] args) {
 String[] ips = {"10.2.4.23","192.168.1.2","173.68.46.65","191.158.6.2","9.2.4.23"};
 
 System.out.println("------1、补零------");
 for (int i = 0; i < ips.length; i++) {
 ips[i] = ips[i].replaceAll("(\\d+)", "00$1");
 System.out.println(ips[i]);
 }
 System.out.println("------2、截取------");
 for (int i = 0; i < ips.length; i++) {
 ips[i] = ips[i].replaceAll("0*(\\d{3})", "$1");
 System.out.println(ips[i]);
 }
 System.out.println("------3、排序------");
 Arrays.sort(ips);
 for (int i = 0; i < ips.length; i++) {
 System.out.println(ips[i]);
 }
 System.out.println("------4、去零------");
 for (int i = 0; i < ips.length; i++) {
 ips[i] = ips[i].replaceAll("0*(\\d+)", "$1");
 System.out.println(ips[i]);
 }
 }
}

------原IP地址------
10.2.4.23
192.168.1.2
173.68.46.65
191.158.6.2
9.2.4.23
------1、加零，按字符串顺序比较------
0010.002.004.0023
00192.00168.001.002
00173.0068.0046.0065
00191.00158.006.002
009.002.004.0023
------2、截取,保留三位------
010.002.004.023
192.168.001.002
173.068.046.065
191.158.006.002
009.002.004.023
------3、排序------
009.002.004.023
010.002.004.023
173.068.046.065
191.158.006.002
192.168.001.002
------4、去零------
9.2.4.23
10.2.4.23
173.68.46.65
191.158.6.2
192.168.1.2