Question

我有两个长度未知的byte[]数组，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;

我尝试过使用arraycopy()，但似乎无法让它发挥作用。

Answer 1

使用System.arraycopy()，以下内容应该有效：

// 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

也许是最简单的方法：

ByteArrayOutputStream output = new ByteArrayOutputStream();

output.write(ciphertext);
output.write(mac);

byte[] out = output.toByteArray();

Answer 3

您需要将out声明为字节数组，其长度等于ciphertext和mac的长度，然后复制ciphertext out和mac最后使用arraycopy。

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 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，您需要分配一个组合长度的数组，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

我编写了以下几个数组连接的过程：

  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

将byte []附加到另一个byte []的末尾

6 个答案: