Java正则表达式

import java.util.Scanner;

public class IntegerDemo {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner sc = new Scanner(System.in);
		System.out.println("请输入你的QQ号码：");
		String qq = sc.nextLine();// 录入QQ号码

		System.out.println(checkQQ(qq));// 输出校验
	}

	public static boolean checkQQ(String qq)// 校验
	{
		boolean flag = true;

		if (qq.length() >= 5 && qq.length() <= 15 && !qq.startsWith("0")) {
			char chs[] = qq.toCharArray();

			for (int i = 0; i < chs.length; i++) {
				char ch = chs[i];

				if (!Character.isDigit(ch)) {
					flag = false;
					break;
				}
			}
		} else {
			flag = false;
		}

		return flag;
	}
}