In a previous post “Installing Java and JavaFX on the Raspberry Pi”, you can read how to install BellSoft LibericaJDK to be able to run JavaFX applications with a graphical user interface on a Raspberry Pi with ARMv7 or ARMv8 processor.

在上一篇文章“在Raspberry Pi上安装Java和JavaFX”中 ，您可以阅读如何安装BellSoft LibericaJDK以便能够在具有ARMv7或ARMv8处理器的Raspberry Pi上以图形用户界面运行JavaFX应用程序。

But this won’t work for some (older) versions of the Raspberry Pi as these use an ARMv6 processor which is not compatible with the default OpenJDK 11 which is part of Raspbian OS.

但这不适用于某些(较旧)版本的Raspberry Pi，因为这些版本使用ARMv6处理器，该处理器与Raspbian OS的默认OpenJDK 11不兼容。

This post will guide you through the steps to have a working Java JDK and JavaFX 11 on these Raspberry Pi board versions.

这篇文章将指导您完成在这些Raspberry Pi电路板版本上运行Java JDK和JavaFX 11的步骤。

准备一个ARMv6 Raspberry Pi板 (Prepare an ARMv6 Raspberry Pi board)

For this post, I’m using an old Raspberry Pi B+ 1.2. To be sure which ARM-version is used, check the output of “cat /proc/cpuinfo” in the terminal:

对于这篇文章，我使用的是旧的Raspberry Pi B + 1.2。 要确定使用哪个ARM版本，请在终端中检查“ cat / proc / cpuinfo”的输出：

$ cat /proc/cpuinfoprocessor  : 0model name : ARMv6-compatible processor rev 7 (v6l)BogoMIPS  : 697.95Features  : half thumb fastmult vfp edsp java tls CPU implementer   : 0x41CPU architecture: 7CPU variant    : 0x0CPU part : 0xb76CPU revision   : 7Hardware   : BCM2835Revision : 0010Serial      : 000000005f9ba615Model       : Raspberry Pi Model B Plus Rev 1.2

For a clear overview of the different board- and ARM-version, check this table on Wikipedia. The boards with ARMv6 are:

要清楚了解不同的Board版本和ARM版本，请查看Wikipedia上的此表 。 ARMv6的主板是：

• Raspberry Pi 1 A and A+
  Raspberry Pi 1 A和A +
• Raspberry Pi 1 B and B+
  Raspberry Pi 1 B和B +
• Compute Module 1
  计算模块1
• Zero 1.2, 1.3 and W
  零1.2、1.3和W

使用Raspbian OS准备SD卡(完整) (Prepare SD card with Raspbian OS (Full))

We start with a fresh new Raspbian OS on the SD card using the “Imager” tool.

我们首先使用“ Imager”工具在SD卡上使用全新的Raspbian OS。

When we now boot the Rasberry Pi board with an ARMv6 processor and check the Java version we get this result:

现在，当我们使用ARMv6处理器启动Rasberry Pi板并检查Java版本时，将得到以下结果：

$ java -version Error occurred during initialization of VM Server VM is only supported on ARMv7+ VFP

As expected, the default included OpenJDK for ARM is build for version 7 or higher, so doesn’t work on this ARMv6-based Raspberry Pi B+ 1.2.

不出所料，默认包含的OpenJDK for ARM是为版本7或更高版本构建的，因此在基于ARMv6的Raspberry Pi B + 1.2上不起作用。

关于Java JDK (About Java JDK)

The sources of Java are available through the open-source project OpenJDK. So anyone can build Java JDK packages — yes you can even do it yourself! — and luckily a lot of free pre-build versions are available.

Java的源代码可通过开源项目OpenJDK获得 。 因此任何人都可以构建Java JDK软件包-是的，您甚至可以自己做 ！ —幸运的是，有许多免费的预构建版本可用。

安装Azul提供的Java 11 for ARMv6 (Install Java 11 for ARMv6 provided by Azul)

Only Azul seems to provide an ARMv6 version with there Zulu JDK, which is available for free!

只有Azul似乎提供带有Zulu JDK的ARMv6版本，该版本是免费的！

Let’s get it from their download page and extract it on our Raspberry Pi.

让我们从他们的下载页面获取它，并将其解压缩到我们的Raspberry Pi中。

$ cd /usr/lib/jvm$ sudo wget https://cdn.azul.com/zulu-embedded/bin/zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf.tar.gz$ sudo tar -xzvf zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf.tar.gz$ sudo rm zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf.tar.gz$ ls -ltotal 12lrwxrwxrwx  1 root root   21 Jul 23 15:58 java-1.11.0-openjdk-armhf -> java-11-openjdk-armhfdrwxr-xr-x  9 root root 4096 Aug 20 11:41 java-11-openjdk-armhfdrwxr-xr-x  2 root root 4096 Aug 20 11:41 openjdk-11drwxrwxr-x 10  111  122 4096 Jul 10 16:50 zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf

OK, there it is! A new JDK on our board. Now let’s configure the OS to be aware of this new one.

好，那里！ 我们板上的一个新JDK。 现在，我们将操作系统配置为了解这一新操作系统。

$ sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf/bin/java 1$ sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf/bin/javac 1

Now we can select the new JDK so it’s linked to the “java” and “javac” command.

现在，我们可以选择新的JDK，以便将其链接到“ java”和“ javac”命令。

$ sudo update-alternatives --config javaThere are 2 choices for the alternative java (providing /usr/bin/java).  Selection    Path                                                             Priority   Status------------------------------------------------------------* 0            /usr/lib/jvm/java-11-openjdk-armhf/bin/java                       1111      auto mode  1            /usr/lib/jvm/java-11-openjdk-armhf/bin/java                       1111      manual mode  2            /usr/lib/jvm/zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf/bin/java   1         manual modePress <enter> to keep the current choice[*], or type selection number: 2update-alternatives: using /usr/lib/jvm/zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf/bin/java to provide /usr/bin/java (java) in manual mode$ sudo update-alternatives --config javacThere are 2 choices for the alternative javac (providing /usr/bin/javac).  Selection    Path                                                              Priority   Status------------------------------------------------------------* 0            /usr/lib/jvm/java-11-openjdk-armhf/bin/javac                       1111      auto mode  1            /usr/lib/jvm/java-11-openjdk-armhf/bin/javac                       1111      manual mode  2            /usr/lib/jvm/zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf/bin/javac   1         manual modePress <enter> to keep the current choice[*], or type selection number: 2update-alternatives: using /usr/lib/jvm/zulu11.41.75-ca-jdk11.0.8-linux_aarch32hf/bin/javac to provide /usr/bin/javac (javac) in manual mode

If everything went well, we should be able to check the Java version now…

如果一切顺利，我们现在应该可以检查Java版本…

$ java -version openjdk version "11.0.8" 2020-07-14 LTS OpenJDK Runtime Environment Zulu11.41+75-CA (build 11.0.8+10-LTS) OpenJDK Client VM Zulu11.41+75-CA (build 11.0.8+10-LTS, mixed mode)

We have a winner! We now successfully replaced the default OpenJDK 11 (which only works on ARMv7+) with the Azul Zulu JDK which works on ARMv6.

我们有赢家！ 现在，我们成功地将默认的OpenJDK 11(仅适用于ARMv7 +)替换为适用于ARMv6的Azul Zulu JDK。

使用未编译的Java文件进行测试 (Testing with a non-compiled Java file)

Let’s try out the newly installed Java JDK. Since Java 11, we can run Java-files directly without the need to compile them. Let’s create a simple file with nano and run it.

让我们尝试一下新安装的Java JDK。 从Java 11开始，我们无需编译即可直接运行Java文件。 让我们用nano创建一个简单的文件并运行它。

$ cd /home/pi$ nano HelloWorld.javapublic class HelloWorld {    public static void main (String[] args) {        System.out.println("Hello World");    }}$ java HelloWorld.javaHello World

Perfect! Java works as expected, but it takes about 15 seconds before the “Hello World” is shown on this old board dating from 2014.

完善！ Java可以按预期工作，但是要花15秒钟的时间才能在2014年的旧主板上显示“ Hello World”。

JavaFX图形用户界面 (Graphical user interfaces with JavaFX)

If you also want to use JavaFX user interfaces, additional steps are needed as this library is not included in the JDK 11. It is developed as an independant open-source project on openjfx.io. The main contributor and maintainer is Gluon. They also offer commercial support to companies who want to use JavaFX for desktop and mobile application development.

如果您还想使用JavaFX用户界面，则需要额外的步骤，因为JDK 11中不包含该库。它是作为openjfx.io上的独立开源项目开发的 。 主要贡献者和维护者是Gluon 。 他们还为希望使用JavaFX进行桌面和移动应用程序开发的公司提供商业支持 。

Make sure you successfully updated to Azul Zulu JDK 11 before proceeding with the next steps.

在继续下一步之前，请确保您已成功更新到Azul Zulu JDK 11。

安装GluonHQ提供的Javav 11 for ARMv6 (Install JavaFX 11 for ARMv6 provided by GluonHQ)

We are going to use the free public version provided by Gluon on their download page.

我们将在其下载页面上使用Gluon提供的免费公共版本。

$ cd /home/pi $ wget -O javafx.zip https://gluonhq.com/download/javafx-11-0-2-sdk-armv6hf/ $ unzip javafx.zip $ rm javafx.zip

We can now check the JavaFX library which was unpacked in “armv6hf-sdk”:

现在，我们可以检查在“ armv6hf-sdk”中解压缩的JavaFX库：

pi@raspberrypi:~ $ ls -ltotal 44drwxr-xr-x 4 pi pi 4096 Mar 12  2019 armv6hf-sdkdrwxr-xr-x 2 pi pi 4096 Aug 20 11:40 Bookshelfdrwxr-xr-x 2 pi pi 4096 Aug 20 12:10 Desktop...$ ls -l armv6hf-sdk/total 8drwxr-xr-x 8 pi pi 4096 Mar 12  2019 legaldrwxr-xr-x 2 pi pi 4096 Mar 12  2019 lib$ ls -l armv6hf-sdk/lib/total 17124-rw-r--r-- 1 pi pi  845637 Mar 12  2019 javafx.base.jar-rw-r--r-- 1 pi pi 2761905 Mar 12  2019 javafx.controls.jar-rw-r--r-- 1 pi pi  143926 Mar 12  2019 javafx.fxml.jar-rw-r--r-- 1 pi pi 5270589 Mar 12  2019 javafx.graphics.jar-rw-r--r-- 1 pi pi  294822 Mar 12  2019 javafx.media.jar-rw-r--r-- 1 pi pi     992 Mar 12  2019 javafx.platform.properties-rw-r--r-- 1 pi pi     113 Mar 12  2019 javafx.properties-rw-r--r-- 1 pi pi   41802 Mar 12  2019 javafx-swt.jar-rw-r--r-- 1 pi pi  786021 Mar 12  2019 javafx.web.jar-rwxr-xr-x 1 pi pi   61200 Mar 12  2019 libdecora_sse.so-rwxr-xr-x 1 pi pi   31428 Mar 12  2019 libglass_monocle.so-rwxr-xr-x 1 pi pi   15946 Mar 12  2019 libglass_monocle_x11.so-rwxr-xr-x 1 pi pi  200074 Mar 12  2019 libglass.so-rwxr-xr-x 1 pi pi   22409 Mar 12  2019 libjavafx_font_freetype.so-rwxr-xr-x 1 pi pi   20508 Mar 12  2019 libjavafx_font_pango.so-rwxr-xr-x 1 pi pi   15206 Mar 12  2019 libjavafx_font.so-rwxr-xr-x 1 pi pi  231402 Mar 12  2019 libjavafx_iio.so-rwxr-xr-x 1 pi pi   43339 Mar 12  2019 libprism_common.so-rwxr-xr-x 1 pi pi   54506 Mar 12  2019 libprism_es2_monocle.so-rwxr-xr-x 1 pi pi   56505 Mar 12  2019 libprism_sw.so-rw-r--r-- 1 pi pi 6598638 Mar 12  2019 src.zip

使用最小的JavaFX应用程序进行测试 (Test with a minimal JavaFX application)

We are going to reuse the minimal JavaFX application which was created in this post “PiJava — Part 4 — Building a minimal JavaFX 11 application with Maven”. First, we need to clone the sources from GitHub:

我们将重复使用本文“ PiJava-第4部分-使用Maven构建最小的JavaFX 11应用程序”中创建的最小的JavaFX应用程序 。 首先，我们需要从GitHub克隆源：

$ cd /home/pi $ git clone https://github.com/FDelporte/MinimalJavaFx11Application.git

To be able to build the application, we also need Maven to be installed.

为了能够构建应用程序，我们还需要安装Maven。

$ sudo apt install maven

Now let’s build the application:

现在让我们构建应用程序：

$ cd MinimalJavaFx11Application $ mvn clean package

This will take some time as all the dependencies need to be downloaded.

这将需要一些时间，因为需要下载所有依赖项。

When finished, we can now run the application with the following start command which points to the downloaded JavaFX library and the generated jar-application in the out-directory of “MinimalJavaFx11Application”:

完成后，我们现在可以使用以下启动命令运行该应用程序，该命令指向下载的JavaFX库和“ MinimalJavaFx11Application”的输出目录中生成的jar应用程序：

$ sudo java --module-path /home/pi/armv6hf-sdk/lib       --add-modules=javafx.controls       -jar /home/pi/MinimalJavaFx11Application/out/MinimalJavaFx11Application-0.1-SNAPSHOT.jar

And there we have it! JavaFX running on an ARMv6 Raspberry Pi B+ 1.2!!!

我们终于得到它了！ 在ARMv6 Raspberry Pi B + 1.2上运行的JavaFX ！！！

结论 (Conclusion)

Compared to the latest Raspberry Pi with a much faster processor and more memory, the application starts a lot slower on my 6-year old test board. But it works! Yes, really, it works :-)

与具有更快处理器和更多内存的最新Raspberry Pi相比，在我使用了6年的测试板上，该应用程序的启动速度要慢得多。 但这有效！ 是的，真的，它有效:-)

Again this small-superhero-board proves to be able to handle everything, even the most modern Java versions on an old processor.

再次证明了这种小型超级英雄板能够处理所有内容，即使是旧处理器上最现代的Java版本也是如此。

And, if you like video, here is the video from Javarevisited Youtube Channel on how to install Java on Raspberry PI

而且，如果您喜欢视频，这是Javarevisited Youtube Channel上有关如何在Raspberry PI上安装Java的视频。

And, If you like this video and want to learn more you can also check the full course here — Use Java and Java FX on a Raspberry PI

而且，如果您喜欢此视频并希望了解更多信息，还可以在此处查看完整的课程- 在Raspberry PI上使用Java和Java FX

Originally published at https://webtechie.be.

最初发布在 https://webtechie.be 。