Java 正则表达式－－匹配字符获取、IP地址排序

 

package Regex;import java.util.regex.*;import java.util.*;public class RegexGet {public static void main(String args[]){//get();//test_1();test_2();}public static void get(){String str=  "good good study,day day up ";String regex ="\\b[a-z]{4}\\b";  //取由四个字符组成的单词Pattern p = Pattern.compile(regex);//System.out.println(p);Matcher m = p.matcher(str);while(m.find()){System.out.println(m.group()+m.start()+"---"+m.end());}}/* * 练习1 *  将　我我......要要要要要.......学......学学.......编编..........程　转成 * 我要学编程　 *  * */public static void test_1(){String str = "我我......要要要要要.......学......学学.......编编..........程";// 先将里面的点全部替换掉String regex ="\\.+";str=str.replaceAll(regex,"");//　下面将重复出现的字符只保留一个 regex="(.)\\1+"; str=str.replaceAll(regex,"$1");System.out.println(str);}/*练习二 * 对　给出的IP　地址进行排序 * 192.68.1.254 102.49.23.13 10.10.10.10 2.2.2.2. 8.109.90.30 *  */public static void test_2(){String ip = "192.68.1.254 102.49.23.13 10.10.10.10 2.2.2.2 8.109.90.30";// 先对IP每一位都添加两个0String regex = "(\\d+)";ip = ip.replaceAll(regex,"00$1");// 再将IP地址只保留三位regex = "0*(\\d{3})";ip = ip.replaceAll(regex,"$1");// 下面进行切割String[] result = ip.split(" +");Arrays.sort(result);System.out.println("after");for(int i =0;i<result.length;i++)result[i]=result[i].replaceAll("0*(\\d+)","$1");  // 将前面的0　去掉for(String s : result)System.out.println(s);}}