java IO to copy one File to another
Solution 1
No, there is no built-in method to do that. The closest to what you want to accomplish is the transferFrom
method from FileOutputStream
, like so:
FileChannel src = new FileInputStream(file1).getChannel();
FileChannel dest = new FileOutputStream(file2).getChannel();
dest.transferFrom(src, 0, src.size());
And don't forget to handle exceptions and close everything in a finally
block.
Solution 2
If you want to be lazy and get away with writing minimal code use
FileUtils.copyFile(src, dest)
from Apache IOCommons
Solution 3
No. Every long-time Java programmer has their own utility belt that includes such a method. Here's mine.
public static void copyFileToFile(final File src, final File dest) throws IOException
{
copyInputStreamToFile(new FileInputStream(src), dest);
dest.setLastModified(src.lastModified());
}
public static void copyInputStreamToFile(final InputStream in, final File dest)
throws IOException
{
copyInputStreamToOutputStream(in, new FileOutputStream(dest));
}
public static void copyInputStreamToOutputStream(final InputStream in,
final OutputStream out) throws IOException
{
try
{
try
{
final byte[] buffer = new byte[1024];
int n;
while ((n = in.read(buffer)) != -1)
out.write(buffer, 0, n);
}
finally
{
out.close();
}
}
finally
{
in.close();
}
}
Solution 4
Since Java 7 you can use Files.copy()
from Java's standard library.
You can create a wrapper method:
public static void copy(String sourcePath, String destinationPath) throws IOException {
Files.copy(Paths.get(sourcePath), new FileOutputStream(destinationPath));
}
that can be used in the following way:
copy("source.txt", "dest.txt");
Solution 5
In Java 7 you can use Files.copy()
and very important is: Do not forget to close the OutputStream after creating the new file.
OutputStream os = new FileOutputStream(targetFile);
Files.copy(Paths.get(sourceFile), os);
os.close();
Comments
-
Aly almost 2 years
I have two Java.io.File objects file1 and file2. I want to copy the contents from file1 to file2. Is there an standard way to do this without me having to create a method that reads file1 and write to file2
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vkraemer about 14 yearsA more complete (and correct) version of this answer is available here: stackoverflow.com/questions/106770/…. Thanks to stackoverflow.com/users/92937/twentymiles for schooling all of us.
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Jeremy Goodell about 10 yearsI'm a fan of minimal code. Not sure why it's "lazy" to use a utility package. I love StringUtils.
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Mahmoud Turki almost 5 yearsfor files and strings, you would rather use the Utils classes like FileUtils and StringUtils. They have a wide range of predefined methods to manipulate files and strings. They are included in the Apache Common package which you can add it ot your pom.xml