Bytes Array 转化

最近 作一个Cassandra 的项目，需要bytes[]和各种类型的转换，java 干了这么多年，应该是信手拈来，但是我错了，搞了半天才搞出来， 惭愧呀

	public static final byte[] bytes(String s) {
		try {
			return s.getBytes("UTF-8");
		} catch (UnsupportedEncodingException e) {
			throw new AssertionError(
					"Cannot happen because this *is* valid encoding.");
		}
	}

	/** Encode a long in big-endian order */
	public static final byte[] bytes(long n) {
		ByteBuffer buf = ByteBuffer.allocate(8);
		buf.putLong(n);
		return buf.array();
	}

	/** Encode a long in big-endian order */
	public static final byte[] bytes(int n) {
		ByteBuffer buf = ByteBuffer.allocate(4);
		buf.putInt(n);
		return buf.array();
	}

	
	public static final String bytes2String(byte[] bs) {
		try {
			return new String(bs, "UTF-8");
		} catch (UnsupportedEncodingException e) {
			throw new AssertionError(
					"Cannot happen because this *is* valid encoding.");
		}
	}

	/** Decode a long in big-endian order */
	public static final long bytes2Long(byte[] bs){
		assert bs.length==8;
		ByteBuffer bb = ByteBuffer.wrap(bs);
		return bb.getLong();
//		ByteBuffer buf = ByteBuffer.allocate(8);
//		buf.put(bs);
//		return buf.getLong();
	}
	
	public static final int bytes2Int(byte[] bs){
		assert bs.length==4;
		ByteBuffer bb = ByteBuffer.wrap(bs);
		return bb.getInt();
	}