Java中的正整数怎么利用正则表达式进行验证

package des;import java.util.regex.Matcher;import java.util.regex.Pattern;public class Num {  public static void main(String[] args) { // TODO Auto-generated method stub Num p=new Num();    String ii="10";    String ii2="0";    String ii3="00";    String ii4="009";    String ii5="3g0";    String ii6="3re";    String ii7="ss";    String ii8="gg031";    String ii9="45*";    String ii10="12.435";    String ii11="3b33";    String ii12="g'gf";    String ii13="1222";    System.out.println("来自 www.jb51.net 的测试结果：");    p.isMatches(ii);    p.isMatches(ii2);    p.isMatches(ii3);    p.isMatches(ii4);    p.isMatches(ii5);    p.isMatches(ii6);    p.isMatches(ii7);    p.isMatches(ii8);    p.isMatches(ii9);    p.isMatches(ii10);    p.isMatches(ii11);    p.isMatches(ii12);    p.isMatches(ii13); } //是否数字 public boolean isMatches(String bot){ boolean flag=false; try{  String regex="^[1-9]+[0-9]*$";  //^[1-9]+\\d*$  Pattern p=Pattern.compile(regex);  Matcher m=p.matcher(bot);  if(m.find()){   System.out.println("successss");  return true;  }else{  System.out.println("falsss");  } }catch(Exception e){  e.printStackTrace(); } return flag; }}