java - 我可以使用 addAll Collection 方法添加所有元素(类型 :byte) from arrays(byte[]) to a List of type Byte?

Question

我必须附加(可变数量的)字节数组。集合似乎只适用于包装类，即 Byte。大约 20 小时后，我想到了这个，并且它有效，但我想知道它是否可以改进(添加到列表，但欢迎任何其他改进建议:)，即

Collections.addAll method all the array elements to the specified collection. This is how Collections.addAll method is being called. It does the same as Arrays.asList method however it is much faster than it so performance wise this is a best way to get the array converted to ArrayList.

这是它当前的测试版

public static byte[] joinArrays(byte[]... args) {

    List<Byte> arrayList = new ArrayList(); 

    for (byte[] arg : args) { // For all array arguments...
        for (int i = 0; i < arg.length; i++) { // For all elements in array
            arrayList.add(Byte.valueOf(arg[i])); // ADD TO LIST
        }
    }
    byte[] returnArray = new byte[arrayList.size()]; 

    for (int i = 0; i < arrayList.size(); i++) {
        returnArray[i] = arrayList.get(i).byteValue(); //Get byte from Byte List
    }
    return returnArray;
}

Answer 1

你可以坚持你的数组并避免装箱/拆箱到 Byte 中，像这样:

public static byte[] joinArrays(byte[]... args) {
    int byteCount = 0;
    for (byte[] arg : args) { // For all array arguments...
        byteCount += arg.length;
    }
    byte[] returnArray = new byte[byteCount];
    int offset = 0;
    for (byte[] arg : args) { // For all array arguments...
        System.arraycopy(arg, 0, returnArray, offset, arg.length);
        offset += arg.length;
    }
    return returnArray;
}