判断是否是汉字

对于gb2312来讲, 首字节码位从0×81 至0×FE，尾字节码位分别是0×40 至0×FE
public boolean isGB2312( String str )
{
  char[] chars = str.toCharArray();
  boolean isGB2312 = false;
  for ( int i = 0; i < chars.length; i++ )
  {
    byte[] bytes = ( "" + chars[i] ).getBytes();
    if ( bytes.length == 2 )
    {
      int[] ints = new int[2];
      ints[0] = bytes[0] & 0xff;
      ints[1] = bytes[1] & 0xff;
  if ( ints[0] >= 0x81 && ints[0] <= 0xFE && ints[1] >= 0x40 && ints[1] <= 0xFE )
      {
        isGB2312 = true;
        break;
      }
    }
  }
  return isGB2312;
}