public class TestRegex {

     public static void main(String[] args) {

         String str = "";

         String regex = "";

         // 匹配

         regex = "[1-9][a-z]";

         getMatches(str, regex);

         // 分割

         str = "1a<a>:abc123:</a>";

         regex = ":";

         getSpilt(str, regex);

         // 替换

         str = "1223334444aaabbc";

         String oldChar = "(.)\\1+";

         regex = "$1";

         getReplace(str, oldChar, regex);

         // 截取

         str = "<title>test string</title><a>url</a><content>abc123</content>";

         regex = "<a>(.*)</a>";

         getSubstring(str, regex);

     }

     public static void getMatches(String str, String regex) {

         System.out.println(str.matches(regex));

     }

     public static void getSpilt(String str, String regex) {

         String[] array = str.split(regex);

         for (String t : array) {

             System.out.println(t);

         }

     }

     public static void getReplace(String str, String oldChar, String regex) {

         System.out.println(str.replaceAll(oldChar, regex));

     }

     public static void getSubstring(String str, String regex) {

         Pattern p = Pattern.compile(regex);

         Matcher m = p.matcher(str);

         if (m.find()) {

             System.out.println(m.group(1));

         }

     }

 }