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Java 8: How to copy files written in a list to a TXT file from one directory to another directory?

I have a simple text file called small_reports.txt that looks like:
report_2021_05_02.csv
report_2021_05_05.csv
report_2021_06_08.csv
report_2021_06_25.csv
report_2021_07_02.csv
This reported is generated with my java code and takes in each of these files from the directory /work/dir1/reports and writes them into the file combined_reports.txt and then places the txt file back into /work/dir1/reports.
My question is, for each line in small_reports.txt, find that same file (line) in /work/dir1/reports and then COPY them to a new directory called /work/dir1/smallreports?
Using Java 8 & NIO (which is really helpful and good) I have tried:
Path source = Paths.get("/work/dir1/reports/combined_reports.txt");
Path target = Paths.get("/work/dir1/smallreports/", "combined_reports.txt");
if (Files.notExists(target) && target != null) {
Files.createDirectories(Paths.get(target.toString()));
}
Files.copy(source, target, StandardCopyOption.REPLACE_EXISTING);
But this is just copying the actual txt file combined_reports.txt into the new directory and not the contents inside like i thought it would.

final String SOURCE_DIR = "/tmp";
final String TARGET_DIR = "/tmp/root/delme";
List<String> csvFileNames = Files.readAllLines(FileSystems.getDefault().getPath("small_reports.txt"), Charset.forName("UTF-8"));
for (String csvFileName : csvFileNames) {
Path source = Paths.get(SOURCE_DIR, csvFileName);
Path target = Paths.get(TARGET_DIR, csvFileName);
if (Files.notExists(target) && target != null) {
Files.createDirectories(Paths.get(target.toString()));
}
Files.copy(source, target, StandardCopyOption.REPLACE_EXISTING);
}
Should do it for you. Obviously change the constants appropriately

Copy image to new directory and rename - Java

So far I have a list of images and I want to rename them based on information I get from a database.
List of images:
IBImages = ["foo1", "foo2", "foo3"]
private static void buildTheme(ArrayList<String> IBImages) {
String bundlesPath = "/a/long/path/with/dest/here";
for (int image = 0; image < IBImages.size(); image++) {
String folder = bundlesPath + "/" + image;
File destFolder = new File(folder);
// Create a new folder with the image name if it doesn't already exist
if (!destFolder.exists()) {
destFolder.mkdirs();
// Copy image here and rename based on a list returned from a database.
}
}
}
The JSON you get from the database might look something like this. I want to rename the one image that I have to all of the names in the list of icon_names
{
"icon_name": [
"Icon-40.png",
"Icon-40#2x.png",
"Icon-40#3x.png",
"Icon-Small.png",
"Icon-Small#2x.png",
]
}

You can't have into directory few files with same name at once. You need to either copy your file once and rename it, or create empty file with new name and copy bits from original file into it. Second approach is quite easy with Files class and its copy(source, target, copyOptions...) method.
Here is simple example of copying one file located in images/source/image.jpg to new files in image/target directory while giving them new names.
String[] newNames = { "foo.jpg", "bar.jpg", "baz.jpg" };
Path source = Paths.get("images/source/image.jpg"); //original file
Path targetDir = Paths.get("images/target");
Files.createDirectories(targetDir);//in case target directory didn't exist
for (String name : newNames) {
Path target = targetDir.resolve(name);// create new path ending with `name` content
System.out.println("copying into " + target);
Files.copy(source, target, StandardCopyOption.REPLACE_EXISTING);
// I decided to replace already existing files with same name
}

How to create a text file inside a specific directory?

I am trying to cretae a file SYS_CONFIG_FILE_NAME inside a specific directory SYS_CONFIG_DIR_NAME. using the below posted code, when i run the java program it creates two directories instead of one directory and one text file inside that directory.
The out put of the below code is
SYS_CONFIG/config.txt. But `config.txt` is not a text file it is just a directory named `config.txt`
i referred also to some question in stackoverflow but i could not find a solution. Please let me know what I am missing?
code:
private final static String SYS_CONFIG_DIR_NAME = "SYS_CONFIG";
private final static String SYS_CONFIG_FILE_NAME = "config.txt";
private static File newSysConfigInstance() throws IOException {
// TODO Auto-generated method stub
File f = new File(SYS_CONFIG_FILE_PATH + "/" + SYS_CONFIG_DIR_NAME + "/" + SYS_CONFIG_FILE_NAME);
f.mkdirs();
f.createNewFile();
return f;
}

I would do it that way, you have always to call createNewFile() to create a new instance of the file if it is not created.
File dir = new File(SYS_CONFIG_FILE_PATH, SYS_CONFIG_DIR_NAME);
f.mkdirs(); // this to create the directories need for your path.
File file = new File(dir, SYS_CONFIG_FILE_NAME);
if (file.createNewFile()) {
system.out.prinln("file first created");
}else {
// print a message here
}
return file;

You are telling it to make a directory of the form a/b/c if you want a directory of the form a/b then you should give it the directory you want it to create.
File dir = new File(SYS_CONFIG_FILE_PATH, SYS_CONFIG_DIR_NAME);
f.mkdirs();
return new File(dir, SYS_CONFIG_FILE_NAME);
You don't have to pre-create files before you use them.

Moving files from one directory to another with Java NIO

I am using the NIO libraries but I am getting a strange error when I try to move files from one directory to another.
String yearNow = new SimpleDateFormat("yyyy").format(
Calendar.getInstance().getTime());
try {
DirectoryStream<Path> curYearStream =
Files.newDirectoryStream(sourceDir, "{" + yearNow + "*}");
//Glob for current year
Path newDir = Paths.get(sourceDir + "//" + yearNow);
if (!Files.exists(newDir) || !Files.isDirectory(newDir)) {
Files.createDirectory(newDir);
//create 2014 directory if it doesn't exist
}
}
Iterate over elements that start with "2014" and move them in the new directory (newDir, which is also called 2014)
for (Path p : curYearStream) {
System.out.println(p); //it prints out exactly the files that I need to move
Files.move(p, newDir); //java.nio.file.FileAlreadyExistsException
}
I get the java.nio.file.FileAlreadyExistsException because my folder (2014) already exists. What I actually want to do is move all the files that start with "2014" INSIDE the 2014 directory.

Better not going back to java.io.File and using NIO instead:
Path sourceDir = Paths.get("c:\\source");
Path destinationDir = Paths.get("c:\\dest");
try (DirectoryStream<Path> directoryStream = Files.newDirectoryStream(sourceDir)) {
for (Path path : directoryStream) {
System.out.println("copying " + path.toString());
Path d2 = destinationDir.resolve(path.getFileName());
System.out.println("destination File=" + d2);
Files.move(path, d2, REPLACE_EXISTING);
}
} catch (IOException ex) {
ex.printStackTrace();
}

Files.move is not equivalent to the mv command. It won't detect that the destination is a directory and move files into there.
You have to construct the full destination path, file by file. If you want to copy /src/a.txt to /dest/2014/, the destination path needs to be /dest/2014/a.txt.
You may want to do something like this:
File srcFile = new File("/src/a.txt");
File destDir = new File("/dest/2014");
Path src = srcFile.toPath();
Path dest = new File(destDir, srcFile.getName()).toPath(); // "/dest/2014/a.txt"

Continue with #Andrew's answer
If we use only Files.move(src, dst, StandardCopyOption.REPLACE_EXISTING); then it will delete source directory because we only provide a directory path not an absolute path of a particular file. So it will also delete a source directory when operation will be done.
Let's say source path is /opt/src which contains a csv files and destination path is /opt/dst and I want to move all files from src to dst and I'm using Files.move(src, dst, StandardCopyOption.REPLACE_EXISTING); this then it will move all the files to dst but it will delete a src directory after moving all files because we didn't provide an absolute path of a each file for src as well as dst. We should have to provide src path like /opt/src/foo.csv and dst path like /opt/dst/foo.csv then and then it will not delete a source directory.
DirectoryStream used to iterate over the entries in a directory. A directory stream allows for the convenient use of the for-each construct to iterate over a directory. So we get an absolute path for src and we use resolve method for resolving an absolute path for dst.
Please refer DirectoryStream for more information.

Try this code:
public class App
{
public void moveFromSourceToDestination(String sourceName,String destinationName)
{
File mydir = new File(sourceName);
if (mydir.isDirectory())
{
File[] myContent = mydir.listFiles();
for(int i = 0; i < myContent.length; i++)
{
File file1 = myContent[i];
file1.renameTo(new File(destinationName+file1.getName()));
}
}
}
public static void main(String [] args)
{
App app = new App();
String sourceName = "C:\\Users\\SourceFolder";
String destinationName = "C:\\Users\\DestinationFolder\\";
app.moveFromSourceToDestination(sourceName,destinationName);
}
}

Using java.io.File, its as simple as this:
File srcFile = new File(srcDir, fileName);
srcFile.renameTo(new File(destDir, "a.txt"));

Is it possible to create a NEW zip file using the java FileSystem?

I've successfully modified the contents of a (existing) zip file using the FileSystem provided by java 7, but when I tried to create a NEW zip file by this method it fails, with the error message that says: "zip END header not found", it is logical because of the way I'm doing it, first I create the file (Files.createFile) which is a completely empty file, and then I try to access to its file system , and since the file is empty its impossible to find any header inside the zip, my question is is there any way to create a new zip file completely empty using this method?; the hack that I've considered is adding an empty new ZipEntry to a the zip file and then using that new empty file to crate the file system based on it, but i really want to think that the guys of oracle implemented a better (easier) way to do this with nio and the filesystems...
this is my code (the error appears when creating the file system):
if (!zipLocation.toFile().exists()) {
if (creatingFile) {
Files.createFile(zipLocation);
}else {
return false;
}
} else if (zipLocation.toFile().exists() && !replacing) {
return false;
}
final FileSystem fs = FileSystems.newFileSystem(zipLocation, null);
.
.
.
zipLocation is a Path
creatingFile is a boolean
ANSWER:
in my particular case the answer given didn't work appropriately because of the spaces in the path, therefore i have to do it the way i didn't want to:
Files.createFile(zipLocation);
ZipOutputStream out = new ZipOutputStream(
new FileOutputStream(zipLocation.toFile()));
out.putNextEntry(new ZipEntry(""));
out.closeEntry();
out.close();
it does not mean that the given answer is wrong, it just didn't work for my particular case

As described in The Oracle Site:
public static void createZip(Path zipLocation, Path toBeAdded, String internalPath) throws Throwable {
Map<String, String> env = new HashMap<String, String>();
// check if file exists
env.put("create", String.valueOf(Files.notExists(zipLocation)));
// use a Zip filesystem URI
URI fileUri = zipLocation.toUri(); // here
URI zipUri = new URI("jar:" + fileUri.getScheme(), fileUri.getPath(), null);
System.out.println(zipUri);
// URI uri = URI.create("jar:file:"+zipLocation); // here creates the
// zip
// try with resource
try (FileSystem zipfs = FileSystems.newFileSystem(zipUri, env)) {
// Create internal path in the zipfs
Path internalTargetPath = zipfs.getPath(internalPath);
// Create parent directory
Files.createDirectories(internalTargetPath.getParent());
// copy a file into the zip file
Files.copy(toBeAdded, internalTargetPath, StandardCopyOption.REPLACE_EXISTING);
}
}
public static void main(String[] args) throws Throwable {
Path zipLocation = FileSystems.getDefault().getPath("a.zip").toAbsolutePath();
Path toBeAdded = FileSystems.getDefault().getPath("a.txt").toAbsolutePath();
createZip(zipLocation, toBeAdded, "aa/aa.txt");
}