身份证验证

public class IDCard {
	// wi =2(n-1)(mod 11) 

	final int[] wi = {7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2,1}; 

	// verify digit 
	final int[] vi = {1,0,'X',9,8,7,6,5,4,3,2}; 
	private int[] ai = new int[18]; 
	public IDCard() { } 
	public boolean Verify(String idcard) { 
		if (idcard.length() == 15) { 
			idcard = uptoeighteen(idcard); 
		} 
		if (idcard.length() != 18) { 
			return false; 
		} 
		String verify = idcard.substring(17, 18); 
		if (verify.equals(getVerify(idcard))) { 
			return true; 
		} 
		return false; 
	} 

	public String getVerify(String eightcardid) { 
		int remaining = 0; 
		if (eightcardid.length() == 18) { 
			eightcardid = eightcardid.substring(0, 17); 
		} 
		if (eightcardid.length() == 17) { 
			int sum = 0; 
			for (int i = 0; i < 17; i++) { 
				String k = eightcardid.substring(i, i + 1); 
				ai[i] = Integer.parseInt(k); 
			} 
			for (int i = 0; i < 17; i++) { 
				sum = sum + wi[i] * ai[i]; 
			} 
			remaining = sum % 11; 
		} 
		return remaining == 2 ? "X" : String.valueOf(vi[remaining]); 
	} 

	public String uptoeighteen(String fifteencardid) { 

		String eightcardid = fifteencardid.substring(0,6); 
		eightcardid = eightcardid + "19"; 

		eightcardid = eightcardid + fifteencardid.substring(6,15); 

		eightcardid = eightcardid + getVerify(eightcardid); 
		return eightcardid; 

	} 

	public static void main(String[] args) {
		String idcard1 = "13052119781204208X";
		IDCard idcard = new IDCard();
		boolean flag = idcard.Verify(idcard1);
		System.out.println(flag);
	}
}