###byte[] -> int

int result = ByteBuffer.wrap(bytes).getInt();

或者：

    public static byte[] intToBytes(int i) {  
        byte[] targets = new byte[4];  
        targets[3] = (byte) (i & 0xFF);  
        targets[2] = (byte) (i >> 8 & 0xFF);  
        targets[1] = (byte) (i >> 16 & 0xFF);  
        targets[0] = (byte) (i >> 24 & 0xFF);  
        return targets;  
    }  

###int -> byte[]

byte[] bytes = ByteBuffer.allocate(4).putInt(1695609641).array();

或

  public static int bytesToInt(byte[] bytes, int off) {  
        int b0 = bytes[off] & 0xFF;  
        int b1 = bytes[off + 1] & 0xFF;  
        int b2 = bytes[off + 2] & 0xFF;  
        int b3 = bytes[off + 3] & 0xFF;  
        return (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;  
    }  

   public static byte[] toByteArray(long value) {
        return ByteBuffer.allocate(Long.SIZE / Byte.SIZE).putLong(value).array();
    }

    public static long byteArrayToLong(byte[] bytes) {
        ByteBuffer buffer = ByteBuffer.allocate(8);
        buffer.put(bytes, 0, bytes.length);
        buffer.flip();
        return buffer.getLong();
    }