将byte 附加到另一个byte 的末尾

我有两个byte[]数组，长度未知，我只想将一个附加到另一个的末尾，即：

 byte[] ciphertext = blah; byte[] mac = blah; byte[] out = ciphertext + mac; 

我已经尝试使用arraycopy()但似乎无法让它工作。

Answer 1

使用System.arraycopy() ，类似以下内容应该工作：

 // create a destination array that is the size of the two arrays byte[] destination = new byte[ciphertext.length + mac.length]; // copy ciphertext into start of destination (from pos 0, copy ciphertext.length bytes) System.arraycopy(ciphertext, 0, destination, 0, ciphertext.length); // copy mac into end of destination (from pos ciphertext.length, copy mac.length bytes) System.arraycopy(mac, 0, destination, ciphertext.length, mac.length); 

Answer 2

你需要声明一个字节数组，其长度等于ciphertext和mac加在一起的长度，然后使用arraycopy在out和mac的结尾复制ciphertext 。

 byte[] concatenateByteArrays(byte[] a, byte[] b) { byte[] result = new byte[a.length + b.length]; System.arraycopy(a, 0, result, 0, a.length); System.arraycopy(b, 0, result, a.length, b.length); return result; } 

Answer 3

也许是最简单的方法：

 ByteArrayOutputStream output = new ByteArrayOutputStream(); output.write(ciphertext); output.write(mac); byte[] out = output.toByteArray(); 

Answer 4

当你想只添加2个字节的数组时，其他提供的解决方案很棒，但如果你想继续添加几个byte []块来制作一个：

 byte[] readBytes ; // Your byte array .... //for eg. readBytes = "TestBytes".getBytes(); ByteArrayBuffer mReadBuffer = new ByteArrayBuffer(0 ) ; // Instead of 0, if you know the count of expected number of bytes, nice to input here mReadBuffer.append(readBytes, 0, readBytes.length); // this copies all bytes from readBytes byte array into mReadBuffer // Any new entry of readBytes, you can just append here by repeating the same call. // Finally, if you want the result into byte[] form: byte[] result = mReadBuffer.buffer(); 

Answer 5

首先，您需要分配组合长度的数组，然后使用arraycopy从两个源填充它。

 byte[] ciphertext = blah; byte[] mac = blah; byte[] out = new byte[ciphertext.length + mac.length]; System.arraycopy(ciphertext, 0, out, 0, ciphertext.length); System.arraycopy(mac, 0, out, ciphertext.length, mac.length); 

Answer 6

我编写了以下几个连接数组的过程：

  static public byte[] concat(byte[]... bufs) { if (bufs.length == 0) return null; if (bufs.length == 1) return bufs[0]; for (int i = 0; i < bufs.length - 1; i++) { byte[] res = Arrays.copyOf(bufs[i], bufs[i].length+bufs[i + 1].length); System.arraycopy(bufs[i + 1], 0, res, bufs[i].length, bufs[i + 1].length); bufs[i + 1] = res; } return bufs[bufs.length - 1]; } 

它使用Arrays.copyOf