如何在 Java 中执行特定于操作系统的通知？

Question

我不是一名程序员（我所拥有的任何 Java 知识都来自 School of Hard Knocks）。请原谅我要问的愚蠢问题，并适当回答。

我正在开发的一个 Java 应用程序使用了非常有缺陷的平台无关通知（例如文件已成功下载时）。我想使用平台感知通知。在 Linux 上发出通知的代码非常简单：

import org.gnome.gtk.Gtk;
import org.gnome.notify.Notify;
import org.gnome.notify.Notification;

public class HelloWorld
{
    public static void main(String[] args) {
        Gtk.init(args);
        Notify.init("Hello world");
        Notification Hello = new Notification("Hello world!", "This is an example notification.", "dialog-information");
        Hello.show();
    }
}

在 Mac 上有点复杂，但仍然可行：

interface NsUserNotificationsBridge extends Library {
    NsUserNotificationsBridge instance = (NsUserNotificationsBridge)
            Native.loadLibrary("/usr/local/lib/NsUserNotificationsBridge.dylib", NsUserNotificationsBridge.class);

    public int sendNotification(String title, String subtitle, String text, int timeoffset);
}

它需要从这个 github 存储库获取 dylib：https://github.com/petesh/OSxNotificationCenter

Windows方式是这样的：

import java.awt.*;
import java.awt.TrayIcon.MessageType;

public class TrayIconDemo {

    public static void main(String[] args) throws AWTException {
        if (SystemTray.isSupported()) {
            TrayIconDemo td = new TrayIconDemo();
            td.displayTray();
        } else {
            System.err.println("System tray not supported!");
        }
    }

    public void displayTray() throws AWTException {
        //Obtain only one instance of the SystemTray object
        SystemTray tray = SystemTray.getSystemTray();

        //If the icon is a file
        Image image = Toolkit.getDefaultToolkit().createImage("icon.png");
        //Alternative (if the icon is on the classpath):
        //Image image = Toolkit.getDefaultToolkit().createImage(getClass().getResource("icon.png"));

        TrayIcon trayIcon = new TrayIcon(image, "Tray Demo");
        //Let the system resize the image if needed
        trayIcon.setImageAutoSize(true);
        //Set tooltip text for the tray icon
        trayIcon.setToolTip("System tray icon demo");
        tray.add(trayIcon);

        trayIcon.displayMessage("Hello, World", "notification demo", MessageType.INFO);
    }
}

重点是，我希望这些片段仅在适当的平台上执行；我不希望 Java 在 Windows 上编译 GTK 方法，因为它的依赖项不存在。

如何才能让 Java 识别它，比如“嘿，我正在为 Mac 系统进行编译，所以我使用的是 Mac 版本的代码。”

Answer 1

为了拥有简单、干净、没有额外依赖项的东西，我会放弃所有本机库，而是依赖本机程序，我确信这些程序保证（或至少可能）在每个各自的系统上可用:

String title = "Hello world!";
String message = "This is an example notification.";
Image image = ImageIO.read(getClass().getResource("icon.png"));

String os = System.getProperty("os.name");
if (os.contains("Linux")) {
    ProcessBuilder builder = new ProcessBuilder(
        "zenity",
        "--notification",
        "--text=" + title + "\\n" + message);
    builder.inheritIO().start();
} else if (os.contains("Mac")) {
    ProcessBuilder builder = new ProcessBuilder(
        "osascript", "-e",
        "display notification \"" + message + "\""
            + " with title \"" + title + "\"");
    builder.inheritIO().start();
} else if (SystemTray.isSupported()) {
    SystemTray tray = SystemTray.getSystemTray();

    TrayIcon trayIcon = new TrayIcon(image, "Tray Demo");
    trayIcon.setImageAutoSize(true);
    tray.add(trayIcon);

    trayIcon.displayMessage(title, message, TrayIcon.MessageType.INFO);
}