如何在android中复制一个文件?

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);
}
}
}
}

或者，你也可以使用FileChannel来复制文件。当复制一个大文件时，它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();
}

下面是一个解决方案，如果在复制时发生错误，它实际上会关闭输入/输出流。这个解决方案利用apache Commons IO IOUtils方法来复制和处理流的关闭。

    public void copyFile(File src, File dst)  {
InputStream in = null;
OutputStream out = null;
try {
in = new FileInputStream(src);
out = new FileOutputStream(dst);
IOUtils.copy(in, out);
} catch (IOException ioe) {
Log.e(LOGTAG, "IOException occurred.", ioe);
} finally {
IOUtils.closeQuietly(out);
IOUtils.closeQuietly(in);
}
}

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();
}
}
}

现在回答可能太迟了，但最方便的方法是使用

FileUtils的

static void copyFile(File srcFile, File destFile)

这就是我所做的

｀

private String copy(String original, int copyNumber){
String copy_path = path + "_copy" + copyNumber;
try {
FileUtils.copyFile(new File(path), new File(copy_path));
return copy_path;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}

｀

Kotlin扩展它

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

  @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

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

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

简单易行的方法!

import android.os.FileUtils;


try (InputStream in = new FileInputStream(sourceFile);
OutputStream out = new FileOutputStream(destinationFile) ){
                

FileUtils.copy(in, out);


}catch(Exception e){
Log.d("ReactNative","Error copying file: "+e.getMessage());
}