convert byte to int in Big endian mode

DataConvUtil.java

	public static int byteToInt(byte[] b,int start) {
		int s = 0;
		int s0 = b[start] & 0xff;// 最低位
		int s1 = b[start+1] & 0xff;
		int s2 = b[start+2] & 0xff;
		int s3 = b[start+3] & 0xff;
		s3 <<= 24;
		s2 <<= 16;
		s1 <<= 8;
		s = s0 | s1 | s2 | s3;
		return s;
	}