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();
}

这些对我来说很有效

public static void copyFileOrDirectory(String srcDir, String dstDir) {

    try {
        File src = new File(srcDir);
        File dst = new File(dstDir, src.getName());

        if (src.isDirectory()) {

            String files[] = src.list();
            int filesLength = files.length;
            for (int i = 0; i < filesLength; i++) {
                String src1 = (new File(src, files[i]).getPath());
                String dst1 = dst.getPath();
                copyFileOrDirectory(src1, dst1);

            }
        } else {
            copyFile(src, dst);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

public static void copyFile(File sourceFile, File destFile) throws IOException {
    if (!destFile.getParentFile().exists())
        destFile.getParentFile().mkdirs();

    if (!destFile.exists()) {
        destFile.createNewFile();
    }

    FileChannel source = null;
    FileChannel destination = null;

    try {
        source = new FileInputStream(sourceFile).getChannel();
        destination = new FileOutputStream(destFile).getChannel();
        destination.transferFrom(source, 0, source.size());
    } finally {
        if (source != null) {
            source.close();
        }
        if (destination != null) {
            destination.close();
        }
    }
}

Kotlin扩展它

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

这在Android O (API 26)上很简单，如你所见:

  @RequiresApi(api = Build.VERSION_CODES.O)
  public static void copy(File origin, File dest) throws IOException {
    Files.copy(origin.toPath(), dest.toPath());
  }

现在使用Kotlin要简单得多:

 File("originalFileDir", "originalFile.name")
            .copyTo(File("newFileDir", "newFile.name"), true)

Trueorfalse用于覆盖目标文件

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.io/java.io.-file/copy-to.html