public static String toString(int[] a) {
if (a == null) //非空校验
return "null";
int iMax = a.length - 1;
if (iMax == -1)
return "[]";
StringBuilder b = new StringBuilder();
b.append('[');//"["
for (int i = 0; ; i++) {
b.append(a[i]);
if (i == iMax){
return b.append(']').toString();
}
b.append(", ");
}
}