barcode EAN13 最后一位验证码

/**
* 计算barcode最后一位
* @param code 12位的barcode
* @return
*/
public static String padBarcode(String code){
if( null == code || code.length() != 12 ){
throw new NullPointerException("code 的位数不对！");
}
//补上位数 code
String code_ = code+"0";
int totalEvent = 0;
int totalCardinal = 0;

char[] resolve = code_.toCharArray();
for( int i = 1; i <= resolve.length; i++ )
{
int temp = Integer.parseInt((resolve[i-1])+"");
if( i % 2 == 0 ){
totalEvent += temp;//偶数和
}else{
totalCardinal += temp;//基数和
}
}
int x = ( totalEvent * 3 ) + totalCardinal;

//取x的值   10最小整数倍的数
int all = x;
if( x % 10 != 0 ){
all = ( (x / 10 +1) * 10);
}
return code+(all-x);
}