JAVA intToBytes and bytesToInt

數字存入到字節數組中，和從字節數組中還原數字

//注意高低位問題
public static int bytesToInt(byte[] src, int offset) {
        int value;
        value = (int) ((src[offset] & 0xFF) | ((src[offset + 1] & 0xFF) << 8) | ((src[offset + 2] & 0xFF) << 16) | ((src[offset + 3] & 0xFF) << 24));
        return value;
    }

public static byte[] toByteArray(int i) {
        byte[] bt = new byte[4];
        bt[0] = (byte) (0xff & i);
        bt[1] = (byte) ((0xff00 & i) >> 8);
        bt[2] = (byte) ((0xff0000 & i) >> 16);
        bt[3] = (byte) ((0xff000000 & i) >> 24);
        return bt;
    }