Java（Raspberry pi）线程

Question

我是一名正在学习Java的学生。（特别是Raspberry pi）我对这个multuthread有疑问。 可以编译。 但这在我的工具包中不起作用。 如果您不介意，可以检查我的代码并为我提供帮助吗？ 谢谢...

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.SocketAddress;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.io.File;
import java.io.FileWriter;

public class RcvThread2 implements Runnable{
    private static final int sizeBuf = 50;
    private Socket clientSocket;
    private Logger logger;
    private SocketAddress clientAddress;

public RcvThread2(Socket clntSock, SocketAddress clientAddress, Logger logger) {
    this.clientSocket = clntSock;
    this.logger = logger;
    this.clientAddress = clientAddress;
    }

static class CloseExtends extends Thread {
    static final String GPIO_OUT = "out";
    static final String GPIO_ON = "1";
    static final String GPIO_OFF = "0";
    static final String[] GpioChannels = {"18"};

public static void main(String[] args) {
    FileWriter[] commandChannels;

    try {
        FileWriter unexportFile = new FileWriter("sys/class/gpio/unexport");
    FileWriter exportFile = new FileWriter("sys/class/gpio/gpio/export");

for(String gpioChannel : GpioChannels) {
    System.out.println(gpioChannel);

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

        FileWriter directionFile = new FileWriter("/sys/class/gpio/gpio" + gpioChannel + "/direction");

        directionFile.write(GPIO_OUT);
        directionFile.flush();
    }
    FileWriter commandChannel = new FileWriter("sys/class/gpio/gpio" + GpioChannels[0] + "/value");

    int period = 20;
    int repeatLoop = 25;
    int counter;

    while(true) {
        for(counter = 0; counter < repeatLoop; counter++) {
            commandChannel.write(GPIO_ON);
            commandChannel.flush();
            java.lang.Thread.sleep(2, 20000);

            commandChannel.write(GPIO_OFF);
            commandChannel.flush();
            java.lang.Thread.sleep(period);
        }
        break;
    }
} catch(Exception exception) {
    exception.printStackTrace();
    }
}
}

public void main(){
try {
    InputStream ins = clientSocket.getInputStream();
    OutputStream outs = clientSocket.getOutputStream();

    int rcvBufSize;
    byte[] rcvBuf = new byte[sizeBuf];
    while ((rcvBufSize = ins.read(rcvBuf)) != -1) {

    String rcvData = new String(rcvBuf, 0, rcvBufSize, "UTF-8");

    if(rcvData.compareTo("MotorLock") == 0) {
        CloseExtends te = new CloseExtends();
        te.start();
    }

    if(rcvData.compareTo("MotorOpen") == 0) {
    }

    logger.info("Received data :" + rcvData + " (" + clientAddress + ")");
    outs.write(rcvBuf, 0, rcvBufSize);
    }

    logger.info(clientSocket.getRemoteSocketAddress() + "Closed");
    } catch (IOException ex) {
        logger.log(Level.WARNING, "Exception in RcvThread", ex);
    }finally {
        try{
            clientSocket.close();
                System.out.println("Disconnected! Client IP :" + clientAddress);
                } catch (IOException e) {}
            }
        }
    }

Answer 1

较低的main方法永远不会被调用。 如果您运行程序，它将执行public static void main(String[] args) {方法。

我认为这是您要在第二个线程中运行的方法吗？

如果您声明并使用以下命令运行新线程

CloseExtends te = new CloseExtends(); te.start(); 它将运行线程public void run() {方法。

因此，如果我正确理解了您的意图，则应将CloseExtends类中的main方法的名称更改为thread run方法，并将较低main方法的签名更改为java程序main方法public static void main(String[] args) { 。

如果它不是真正的主要方法，我不会将任何其他方法命名为“主要”。

您可以在此处看到使用Runnable接口创建新线程的示例： https : //docs.oracle.com/javase/tutorial/essential/concurrency/runthread.html