通过名称在目录中找到特定文件，再将文件保存到本地文件夹

Question

I would like to locate a file named SAVE.properties. I have looked at different questions that seem like they would answer me, but I can't see that they do.

For example, I would like to check to see whether or not SAVE.properties exists within a directory (and its subfolders).

I would also like to know how I could save a .properties file (and then read it afterwards from this location) to the directory where my program is being run from. If it is run from the desktop, it should save the .properties file there.

Answer 1

Saving properties can easily be achieved through the use of Properties#store(OutputStream, String) , this allows you to define where the contents is saved to through the use of an OutputStream .

So you could use...

Properties properties = ...;
//...
try (FileOutputStream os = new FileOutputStream(new File("SAVE.properties"))) {
    properties.store(os, "Save");
} catch (IOException exp) {
    exp.printStackTrace();
}

You can also use Properties#load(InputStream) to read the contents of a "properties" file.

Take a closer look at Basic I/O for more details.

Locating a File is as simple as using

 File file = new File("SAVE.properties");
 if (file.exists) {...

This checks the current working directory for the existence of the specified file.

Searching the sub directories is little more involved and will require you to use some recursion, for example...

public File find(File path) {

    File save = new File(path, "SAVE.properties");
    if (!save.exists()) {
        save = null;
        File[] dirs = path.listFiles(new FileFilter() {
            @Override
            public boolean accept(File pathname) {
                return  pathname.isDirectory();
            }
        });
        for (File dir : dirs) {
            save = find(dir);
            if (save != null) {
                break;
            }
        }
    }
    return save;
}

Using find(new File(".")) will start searching from the current working directory. Just beware, under the right circumstances, this could search your entire hard disk.