用Spring boot搭建项目时，希望在项目启动完后能自动谈出首页。

就用了java.awt.Desktop类

        if (Desktop.isDesktopSupported()) {            try {                // 弹出浏览器 - 显示HTTP接口(https)Desktop.getDesktop().browse(new URI("https://blog.csdn.net/weixin_42156742/article/details/81383628"));} catch (Exception e) {LOGGER.info(e.getMessage());}}

结果在测试类里可以正常访问，在启动项目后却无法弹出网页。

public static synchronized Desktop getDesktop(){        if (GraphicsEnvironment.isHeadless()) throw new HeadlessException();        if (!Desktop.isDesktopSupported()) {            throw new UnsupportedOperationException("Desktop API is not " +                                                    "supported on the current platform");}sun.awt.AppContext context = sun.awt.AppContext.getAppContext();Desktop desktop = (Desktop)context.get(Desktop.class);        if (desktop == null) {desktop = new Desktop();context.put(Desktop.class, desktop);}        return desktop;}

private static boolean getHeadlessProperty() {        if (headless == null) {AccessController.doPrivileged((PrivilegedAction<Void>) () -> {String nm = System.getProperty("java.awt.headless");                if (nm == null) {                    /* No need to ask for DISPLAY when run in a browser */if (System.getProperty("javaplugin.version") != null) {headless = defaultHeadless = Boolean.FALSE;} else {String osName = System.getProperty("os.name");                        if (osName.contains("OS X") && "sun.awt.HToolkit".equals(System.getProperty("awt.toolkit"))){headless = defaultHeadless = Boolean.TRUE;} else {                            final String display = System.getenv("DISPLAY");headless = defaultHeadless =("Linux".equals(osName) ||                                 "SunOS".equals(osName) ||                                 "FreeBSD".equals(osName) ||                                 "NetBSD".equals(osName) ||                                 "OpenBSD".equals(osName) ||                                 "AIX".equals(osName)) &&(display == null || display.trim().isEmpty());}}} else {headless = Boolean.valueOf(nm);}                return null;});}        return headless;}

往下排查原因，发现 getHeadlessProperty 方法中 System.getProperty("java.awt.headless") 处获取系统参数时返回了true。

导致直接抛出了HeadlessException异常。Headless模式是在缺少显示屏、键盘或者鼠标时的系统配置，这是此处的参数导致了无法弹出指定窗口。

System.setProperty("java.awt.headless", "false");

所以需要提前设置参数为false。