SwitchOnOff.java

SwitchOnOff.java

/*
 * Java Embedded Raspberry Pi GPIO app
 * スイッチポチポチ♪
 * 用意するもの
 *  ジャンパーケーブル（オス×メス：２本、オス×オス：１本）
 *  タクトスイッチ（モーメンタリ）
 *  抵抗 10kΩ（茶・黒・橙・金）
 */
import java.io.File;
import java.io.FileWriter;
import java.io.RandomAccessFile;

public class SwitchOnOff {
	static final String GPIO_OUT = "out";
	static final String GPIO_IN = "in";
	static final String GPIO_ON = "1";
	static final String GPIO_OFF = "0";
	static final String GPIO_CH = "18";

	public static void main(String[] args) {
		try {
			//Refresh GPIO_CH
			FileWriter unexport = new FileWriter("/sys/class/gpio/unexport");
			FileWriter export = new FileWriter("/sys/class/gpio/export");

			File exportFileCheck = new File("/sys/class/gpio/gpio" + GPIO_CH);
			if (exportFileCheck.exists()) {
				unexport.write(GPIO_CH);
				unexport.flush();
			}

			export.write(GPIO_CH);
			export.flush();

			//Direction GPIO_CH
			FileWriter direction = new FileWriter("/sys/class/gpio/gpio2" + GPIO_CH + "/direction");
			direction.write(GPIO_IN);
			direction.flush();

			// Create GPIO Reader
			RandomAccessFile accesser = new RandomAccessFile("/sys/class/gpio/gpio" + GPIO_CH + "/value", "r");
			byte[] inData = new byte[256];

			//GPIO_CH Read Loop
			while(true) {
				accesser.seek(0);
				accesser.read(inData);
				String data = new String(inData);
				System.out.println(data);
				Thread.sleep(200);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}