Java 多线程共享列表

Question

我需要一些关于 java 多线程的帮助。我有这门课:

public class EdgeServer{

    private static final int ServidorBordaID = 9;
    private static final String urlLogin = "http://localhost/exehdager-teste/index.php/ci_login/logar";
    private static final String insertSensorURI = "http://localhost/exehdager-teste/index.php/cadastros/ci_sensor/gravaSensor";
    private static final String insertGatewayURI = "http://localhost/exehdager-teste/index.php/cadastros/ci_gateway/gravaGateway";
    private static ArrayList<Gateway> gatewaysCadastrados = new ArrayList<>();

    public static void main(String[] args) {
        // Start a user thread that runs the UPnP stack
        Thread clientThread = new Thread(new Descoberta());
        clientThread.setDaemon(false);
        clientThread.start();

        Thread publicationThread = new Thread(new Publication());
        publicationThread.setDaemon(false);
        publicationThread.start();
    }
}

线程 Descoberta 将根据需要将新的 itens 添加到 gatewaysCadastrados 列表中。并且发布线程将读取此列表并对列表中的每个对象执行一个操作。

我只需要知道如何共享这个变量并将其传递给线程。我需要构建一个信号量来执行此操作吗？

Answer 1

这是示例代码，您可以在两个线程之间共享列表，并且需要使用等待和通知信号量。

public class Descoberta extends Thread {
private  final ArrayList<Gateway> a = new ArrayList<>();
public Descoberta( ArrayList<Gateway> a) {
        this.a = a;
    }

    @Override
    public void run() {
         synchronized (a) {
                while(true){ // your condition
                    a.wait();
                }
                a.notify();
         }
    }
}

public class Publication extends Thread {
private  final ArrayList<Gateway> b = new ArrayList<>();
public Publication(ArrayList<Gateway> b) {
        this.b = b;
    }

    @Override
    public void run() {
         synchronized (b) {
                while(true){ // your condition
                    b.wait();
                }
                b.notify();
         }
    }
}

public class EdgeServer {
    public static void main(String args[]) {
        private final ArrayList<Gateway> gatewaysCadastrados = new ArrayList<>();
        Thread clientThread = new Descoberta(gatewaysCadastrados);
        Thread publicationThread = new Publication(gatewaysCadastrados);
        clientThread.start();
        publicationThread.start();
    }
}