在Windows，Mac和Linux上从位置检索文件

Question

Currently, I have a Java application that needs to copy a file from a directory and place it on the Desktop. I have this method

public static void copyFileUsingFileStreams(File source, File dest) throws IOException {

    InputStream input = null;
    OutputStream output = null;

    try {
        input = new FileInputStream(source);
        output = new FileOutputStream(dest);
        byte[] buf = new byte[1024];
        int bytesRead;
        while ((bytesRead = input.read(buf)) > 0) { output.write(buf, 0, bytesRead); }
    } 
    finally {
        input.close();
        output.close();
    }
}

and I call it like below.

copyFileUsingFileStreams(new File("C:/Program Files (x86)/MyProgram/App_Data/Session.db"), new File(System.getProperty("user.home") + "/Desktop/Session.db"));

This works perfectly on Windows. However, I want to be able to do the exact same thing on Mac and Linux machines as well (location is /opt/myprogram/App_Data/Session.db). How can I assess whether the machine running is Windows or Mac/Linux, and how do I restructure my code accordingly?

Answer 1

You can get the OS info using System.getProperty like

String property = System.getProperty("os.name");

Moreover you can use Files.copy() to simplify your code(and if you want more control then use StandardCopyOption ). eg

Files.copy(src, Paths.get("/opt/myprogram/App_Data/Session.db"));

so your updated code can look something like this

public static void copyFileUsingFileStreams(File source, File dest) throws IOException {
    String property = System.getProperty("os.name");

    if (property.equals("Linux")) {
        dest = Paths.get("/opt/myprogram/App_Data/Session.db").toFile();
    }               
    //add code to adjust dest for other os.
    Files.copy(source.toPath(), dest.toPath());
}

Answer 2

您可以使用确定操作系统名称

System.getProperty("os.name")