java - 当前平台不支持桌面 API

Question

我遇到了这个错误:

java.lang.UnsupportedOperationException: Desktop API is not supported on the current platform

我会从我的 java 应用程序中打开一个文件。我用这个方法:

Desktop.getDesktop().open(new File(report.html"));

我该如何解决这个问题？

Answer 1

基本上，问题在于 Java 桌面集成在 Linux 上无法正常工作。

它被设计为在 Windows 上运行良好；有些东西在其他系统上有效，但没有人真正关心为这些系统添加适当的支持。即使您安装了所需的“gnome 库”，结果也会很差。

我不久前也遇到过同样的问题，并想出了下面的类(class)。

目标是通过使用系统特定的命令来实现的:

KDE:     kde-open
GNOME:   gnome-open
Any X-server system: xdg-open
MAC:     open
Windows: explorer

如果这些都不起作用，它会尝试 Java Desktop 提供的实现。
因为这个通常会失败，所以它作为最后的手段进行了尝试。

---

DesktopApi 类

该类提供静态方法open、browse和edit。
它经过测试可在 Linux(Kde 和 Gnome)、Windows 和 Mac 上运行。

如果你使用它，请给我信用。

package net.mightypork.rpack.utils;

import java.awt.Desktop;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;
import java.util.List;


public class DesktopApi {

    public static boolean browse(URI uri) {

        if (openSystemSpecific(uri.toString())) return true;

        if (browseDESKTOP(uri)) return true;

        return false;
    }


    public static boolean open(File file) {

        if (openSystemSpecific(file.getPath())) return true;

        if (openDESKTOP(file)) return true;

        return false;
    }


    public static boolean edit(File file) {

        // you can try something like
        // runCommand("gimp", "%s", file.getPath())
        // based on user preferences.

        if (openSystemSpecific(file.getPath())) return true;

        if (editDESKTOP(file)) return true;

        return false;
    }


    private static boolean openSystemSpecific(String what) {

        EnumOS os = getOs();

        if (os.isLinux()) {
            if (runCommand("kde-open", "%s", what)) return true;
            if (runCommand("gnome-open", "%s", what)) return true;
            if (runCommand("xdg-open", "%s", what)) return true;
        }

        if (os.isMac()) {
            if (runCommand("open", "%s", what)) return true;
        }

        if (os.isWindows()) {
            if (runCommand("explorer", "%s", what)) return true;
        }

        return false;
    }


    private static boolean browseDESKTOP(URI uri) {

        logOut("Trying to use Desktop.getDesktop().browse() with " + uri.toString());
        try {
            if (!Desktop.isDesktopSupported()) {
                logErr("Platform is not supported.");
                return false;
            }

            if (!Desktop.getDesktop().isSupported(Desktop.Action.BROWSE)) {
                logErr("BROWSE is not supported.");
                return false;
            }

            Desktop.getDesktop().browse(uri);

            return true;
        } catch (Throwable t) {
            logErr("Error using desktop browse.", t);
            return false;
        }
    }


    private static boolean openDESKTOP(File file) {

        logOut("Trying to use Desktop.getDesktop().open() with " + file.toString());
        try {
            if (!Desktop.isDesktopSupported()) {
                logErr("Platform is not supported.");
                return false;
            }

            if (!Desktop.getDesktop().isSupported(Desktop.Action.OPEN)) {
                logErr("OPEN is not supported.");
                return false;
            }

            Desktop.getDesktop().open(file);

            return true;
        } catch (Throwable t) {
            logErr("Error using desktop open.", t);
            return false;
        }
    }


    private static boolean editDESKTOP(File file) {

        logOut("Trying to use Desktop.getDesktop().edit() with " + file);
        try {
            if (!Desktop.isDesktopSupported()) {
                logErr("Platform is not supported.");
                return false;
            }

            if (!Desktop.getDesktop().isSupported(Desktop.Action.EDIT)) {
                logErr("EDIT is not supported.");
                return false;
            }

            Desktop.getDesktop().edit(file);

            return true;
        } catch (Throwable t) {
            logErr("Error using desktop edit.", t);
            return false;
        }
    }


    private static boolean runCommand(String command, String args, String file) {

        logOut("Trying to exec:\n   cmd = " + command + "\n   args = " + args + "\n   %s = " + file);

        String[] parts = prepareCommand(command, args, file);

        try {
            Process p = Runtime.getRuntime().exec(parts);
            if (p == null) return false;

            try {
                int retval = p.exitValue();
                if (retval == 0) {
                    logErr("Process ended immediately.");
                    return false;
                } else {
                    logErr("Process crashed.");
                    return false;
                }
            } catch (IllegalThreadStateException itse) {
                logErr("Process is running.");
                return true;
            }
        } catch (IOException e) {
            logErr("Error running command.", e);
            return false;
        }
    }


    private static String[] prepareCommand(String command, String args, String file) {

        List<String> parts = new ArrayList<String>();
        parts.add(command);

        if (args != null) {
            for (String s : args.split(" ")) {
                s = String.format(s, file); // put in the filename thing

                parts.add(s.trim());
            }
        }

        return parts.toArray(new String[parts.size()]);
    }

    private static void logErr(String msg, Throwable t) {
        System.err.println(msg);
        t.printStackTrace();
    }

    private static void logErr(String msg) {
        System.err.println(msg);
    }

    private static void logOut(String msg) {
        System.out.println(msg);
    }

    public static enum EnumOS {
        linux, macos, solaris, unknown, windows;

        public boolean isLinux() {

            return this == linux || this == solaris;
        }


        public boolean isMac() {

            return this == macos;
        }


        public boolean isWindows() {

            return this == windows;
        }
    }


    public static EnumOS getOs() {

        String s = System.getProperty("os.name").toLowerCase();

        if (s.contains("win")) {
            return EnumOS.windows;
        }

        if (s.contains("mac")) {
            return EnumOS.macos;
        }

        if (s.contains("solaris")) {
            return EnumOS.solaris;
        }

        if (s.contains("sunos")) {
            return EnumOS.solaris;
        }

        if (s.contains("linux")) {
            return EnumOS.linux;
        }

        if (s.contains("unix")) {
            return EnumOS.linux;
        } else {
            return EnumOS.unknown;
        }
    }
}