在kotlin中，只需:

val fileSrc : File = File("srcPath")
val fileDest : File = File("destPath")

fileSrc.copyTo(fileDest)

在Kotlin:很短的路

// fromPath : Path the file you want to copy 
// toPath :   The path where you want to save the file
// fileName : name of the file that you want to copy
// newFileName: New name for the copied file (you can put the fileName too instead of put a new name)    

val toPathF = File(toPath)
if (!toPathF.exists()) {
   path.mkdir()
}

File(fromPath, fileName).copyTo(File(toPath, fileName), replace)

这适用于任何文件，如图像和视频

要复制文件并将其保存到目标路径，您可以使用下面的方法。

public static void copy(File src, File dst) throws IOException {
    InputStream in = new FileInputStream(src);
    try {
        OutputStream out = new FileOutputStream(dst);
        try {
            // Transfer bytes from in to out
            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0) {
                out.write(buf, 0, len);
            }
        } finally {
            out.close();
        }
    } finally {
        in.close();
    }
}

在API 19+上，您可以使用Java自动资源管理:

public static void copy(File src, File dst) throws IOException {
    try (InputStream in = new FileInputStream(src)) {
        try (OutputStream out = new FileOutputStream(dst)) {
            // Transfer bytes from in to out
            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0) {
                out.write(buf, 0, len);
            }
        }
    }
}

Kotlin扩展它

fun File.copyTo(file: File) {
    inputStream().use { input ->
        file.outputStream().use { output ->
            input.copyTo(output)
        }
    }
}

或者，您也可以使用FileChannel来复制文件。在复制大文件时，它可能比字节复制方法更快。如果你的文件大于2GB，你就不能使用它。

public void copy(File src, File dst) throws IOException {
    FileInputStream inStream = new FileInputStream(src);
    FileOutputStream outStream = new FileOutputStream(dst);
    FileChannel inChannel = inStream.getChannel();
    FileChannel outChannel = outStream.getChannel();
    inChannel.transferTo(0, inChannel.size(), outChannel);
    inStream.close();
    outStream.close();
}

在kotlin中你可以用

file1.copyTo(file2)

file1是原始文件的对象，而file2是要复制到的新文件的对象