java 接入液晶屏 java控制led屏

目录

1、环境介绍

2、设备介绍

3、前期准备

3.1.给Ubuntu安装jdk

4、编写java代码

        4.1.获取gpio引脚编号和路径

        4.2.编写java代码

        5、在Ubuntu系统上运行

        6.在Ubuntu上使用终端直接控制LED ,操作如下:

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1、环境介绍

• JAVA

Intellij IDEA 2022.3.3 (Ultimate Edition)

jdk-1.8.0_77

• Ubuntu

Linux version 5.10.110 (root@seven-HP-ZHAN-99-Pro-G1-MT) (aarch64-none-linux-gnu-gcc (GNU Toolchain for the A-profile Architecture 10.3-2021.07 (arm-10.29)) 10.3.1 20210621, GNU ld (GNU Toolchain for the A-profile Architecture 10.3-2021.07 (arm-10.29)) 2.36.1.20210621) #11 SMP Fri Feb 10 18:15:24 CST 2023

openjdk version "11.0.18" 2023-01-17
OpenJDK Runtime Environment (build 11.0.18+10-post-Ubuntu-0ubuntu120.04.1)
OpenJDK 64-Bit Server VM (build 11.0.18+10-post-Ubuntu-0ubuntu120.04.1, mixed mode)

2、设备介绍

3、前期准备

3.1.给Ubuntu安装jdk

代码如下（终端）：

armt@localhost:~$ apt-cache search java11

openjdk-11-jdk - OpenJDK Development Kit (JDK)
openjdk-11-jdk-headless - OpenJDK Development Kit (JDK) (headless)
openjdk-11-jre - OpenJDK Java runtime, using Hotspot JIT
openjdk-11-jre-headless - OpenJDK Java runtime, using Hotspot JIT (headless)
default-jdk - Standard Java or Java compatible Development Kit
default-jdk-headless - Standard Java or Java compatible Development Kit (headless)

3.2选择要安装的jdk版本 , 然后输入y进行安装 

armt@localhost:~$ sudo apt-get install openjdk-11-jdk

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  openjdk-11-jdk-headless openjdk-11-jre openjdk-11-jre-headless
Suggested packages:
  openjdk-11-demo openjdk-11-source visualvm fonts-ipafont-gothic
  fonts-ipafont-mincho fonts-wqy-microhei | fonts-wqy-zenhei
The following NEW packages will be installed:
  openjdk-11-jdk openjdk-11-jdk-headless openjdk-11-jre
  openjdk-11-jre-headless
0 upgraded, 4 newly installed, 0 to remove and 4 not upgraded.
Need to get 281 MB of archives.
After this operation, 435 MB of additional disk space will be used.
Do you want to continue? [Y/n] y

3.3 安装完成查看jdk是否安装成, 打印如下结果说明安装成功了

armt@localhost:~$ java -version

openjdk version "11.0.18" 2023-01-17
OpenJDK Runtime Environment (build 11.0.18+10-post-Ubuntu-0ubuntu120.04.1)
OpenJDK 64-Bit Server VM (build 11.0.18+10-post-Ubuntu-0ubuntu120.04.1, mixed mode)

3.4 安装JDK时出现如下错误, 执行  sudo apt update 

4、编写java代码

        本案例采用GPIO的方式控制灯光亮灭,简单来说就是一个接口，通过变换状态值，来达到设备的变化。

        4.1.获取gpio引脚编号和路径

 图中GPIO4_C6 是属于 GPIO4属于第4组引脚, 1组有32个引脚, C6 的 C 组，如果是 A 组的话则为 0，B组为8,  C 组为 16， D 组则为 24，以此递推 ,算出GPIO4_C6的引脚编号为4*32+16+6 =150

        LED_W  表示白色灯     引脚编号150
        LED_G  表示绿色灯     引脚编号149
        LED_R  表示红色灯     引脚编号122

        RK芯片的路径:/sys/class/gpio/

新增其它GPIO口编号:

        GPIO_1_A4  对应引脚编号: 36
        GPIO_2_B0  对应引脚编号: 40
        GPIO_3_B1  对应引脚编号: 41
        GPIO_4_B2  对应引脚编号: 42

        4.2.编写java代码

private static final String GPIO_PATH = "/sys/class/gpio/";//路径

    
    private static final String GPIO_PIN_W = "150"; // 白灯引脚编号
    private static final String GPIO_PIN_G = "149"; // 绿灯引脚编号
    private static final String GPIO_PIN_R = "122"; // 红灯引脚编号

    //如果想控制其他IO口 记得替换引脚编号
    //private static final String GPIO1_A4 = "36";
    //private static final String GPIO1_B0 = "40"; 
    //private static final String GPIO1_B1 = "41";
    //private static final String GPIO1_B2 = "42";

        操作步骤:
                1.导出GPIO引脚

/**
     * 导出GPIO引脚
     */
    private static void exportPin(String pin) {
        writeFile(GPIO_PATH + "export", pin);
    }

                2.设置GPIO引脚为输出模式

/**
     * 设置GPIO引脚为输出模式
     */
    private static void setPinDirection(String pin, String direction) {
        writeFile(GPIO_PATH + "gpio" + pin + "/direction", direction);
    }

                3.控制LED灯开/关

/**
     * 控制LED灯
     */
    private static void setPinValue(String pin, String value) {
        writeFile(GPIO_PATH + "gpio" + pin + "/value", value);
    }

                4.清理GPIO引脚

/**
     * 清理GPIO引脚
     */
    private static void unexportPin(String pin) {
        writeFile(GPIO_PATH + "unexport", pin);
    }

private static void writeFile(String path, String value) {
        try (FileWriter fileWriter = new FileWriter(path)) {
            fileWriter.write(value);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

                打开LED灯

/**
     * 打开灯
     * @param pin 引脚编号
     */
    private static void openLED(String pin){
        //打开前关闭所有led,避免多个灯同时点亮烧坏电路板
        closeLED(GPIO_PIN_W);
        closeLED(GPIO_PIN_G);
        closeLED(GPIO_PIN_R);

        // 导出GPIO引脚
        exportPin(pin);

        // 设置GPIO引脚为输出模式
        setPinDirection(pin, "out");

        // 控制LED灯
        setPinValue(pin, "1"); // 打开LED灯
    }

                关闭LED灯

/**
     * 关闭灯
     * @param pin 引脚编号
     */
    private static void closeLED(String pin){
        // 控制LED灯
        setPinValue(pin, "0"); // 关闭LED灯

        // 清理GPIO引脚
        unexportPin(pin);
    }

        完整代码:

package org.example;

import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.FileWriter;
import java.io.IOException;

public class Main {
    private static final String GPIO_PATH = "/sys/class/gpio/";

    private static final String GPIO_PIN_W = "150"; // 白灯引脚编号
    private static final String GPIO_PIN_G = "149"; // 绿灯引脚编号
    private static final String GPIO_PIN_R = "122"; // 红灯引脚编号

    public static void main(String[] args) {

        createAndShowGUI();
    }

    /**
     * 打开灯
     * @param pin 引脚编号
     */
    private static void openLED(String pin){
        //打开前关闭所有led,避免多个灯同时点亮烧坏电路板
        closeLED(GPIO_PIN_W);
        closeLED(GPIO_PIN_G);
        closeLED(GPIO_PIN_R);

        // 导出GPIO引脚
        exportPin(pin);

        // 设置GPIO引脚为输出模式
        setPinDirection(pin, "out");

        // 控制LED灯
        setPinValue(pin, "1"); // 打开LED灯
    }

    /**
     * 关闭灯
     * @param pin 引脚编号
     */
    private static void closeLED(String pin){
        // 控制LED灯
        setPinValue(pin, "0"); // 关闭LED灯

        // 清理GPIO引脚
        unexportPin(pin);
    }


    /**
     * 导出GPIO引脚
     */
    private static void exportPin(String pin) {
        writeFile(GPIO_PATH + "export", pin);
    }

    /**
     * 清理GPIO引脚
     */
    private static void unexportPin(String pin) {
        writeFile(GPIO_PATH + "unexport", pin);
    }

    /**
     * 设置GPIO引脚为输出模式
     */
    private static void setPinDirection(String pin, String direction) {
        writeFile(GPIO_PATH + "gpio" + pin + "/direction", direction);
    }

    /**
     * 控制LED灯
     */
    private static void setPinValue(String pin, String value) {
        writeFile(GPIO_PATH + "gpio" + pin + "/value", value);
    }


    private static void writeFile(String path, String value) {
        try (FileWriter fileWriter = new FileWriter(path)) {
            fileWriter.write(value);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    /**
     * 创建UI
     */
    private static void createAndShowGUI() {

        JFrame.setDefaultLookAndFeelDecorated(true);
        JFrame frame = new JFrame("GPIO控制LED开关");
        frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                //窗口关闭时关闭LED
                closeLED(GPIO_PIN_W);
                closeLED(GPIO_PIN_G);
                closeLED(GPIO_PIN_R);
            }
        });

        //设置弹窗大小
        frame.setLocation(200, 200);

        JPanel panel = new JPanel();
        panel.setPreferredSize(new Dimension(600, 400));
        panel.setLayout(null);

        // 添加面板
        JButton wBtn = new JButton("打开-白灯");
        wBtn.addActionListener(e -> openLED(GPIO_PIN_W));
        wBtn.setBounds(60, 25, 130, 30);

        JButton gBtn = new JButton("打开-绿灯");
        gBtn.addActionListener(e -> openLED(GPIO_PIN_G));
        gBtn.setBounds(220, 25, 130, 30);

        JButton rBtn = new JButton("打开-红灯");
        rBtn.addActionListener(e -> openLED(GPIO_PIN_R));
        rBtn.setBounds(380, 25, 130, 30);
        // 关闭按钮
        JButton wBtnC = new JButton("关闭-白灯");
        wBtnC.addActionListener(e -> closeLED(GPIO_PIN_W));
        wBtnC.setBounds(60, 75, 130, 30);

        JButton gBtnC = new JButton("关闭-绿灯");
        gBtnC.addActionListener(e -> closeLED(GPIO_PIN_G));
        gBtnC.setBounds(220, 75, 130, 30);

        JButton rBtnC = new JButton("关闭-红灯");
        rBtnC.addActionListener(e -> closeLED(GPIO_PIN_R));
        rBtnC.setBounds(380, 75, 130, 30);


        panel.add(wBtn);
        panel.add(gBtn);
        panel.add(rBtn);
        panel.add(wBtnC);
        panel.add(gBtnC);
        panel.add(rBtnC);


        frame.add(panel);

        // 显示窗口
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

        5、在Ubuntu系统上运行

                将java程序导出jar包(testGPIO.jar ,名称随便取), 放在任意位置, 打开终端后输入 :

        java -jar  testGPIO.jar

                 软件运行图如下:

        6.在Ubuntu上使用终端直接控制LED ,操作如下: