循环中的并发与循环

Question

我一直在阅读关于Swing中的Java Concurrency,并且无法找到适合我情况的答案.

目标:让我的swing应用程序同时运行while循环,直到程序/应用程序退出.

问题:程序冻结(正如我之前预期的那样)并且无法使用.

尝试 - 解决方案:我试图在另一个线程上启动while循环,启动它,仍然没有.

码:

package stakeme;

import java.io.IOException;

import javax.swing.SwingUtilities;

public class StakeMeServer {

    private static ServerSocket socket;

    public static Thread t;


    public static void main(String[] args) throws IOException {


        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new ConsoleGUI("Server", 800, 400, false);
            }

        });

        Thread t = new Thread(() -> {
            System.out.println("1");
            while (online) {
                System.out.println("2");
            }
        });
        t.setName("GameServer");
        t.start();
    }

}

更新:通过使用SwingWorker类在后台执行我的while循环,我几乎可以做我需要做的事情.

码:

package stakeme;

import java.io.IOException;
import java.util.concurrent.atomic.AtomicBoolean;

import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class StakeMeServer {

    private static AtomicBoolean online = new AtomicBoolean(false);

    public static GameServerLoop gsl = new GameServerLoop();


    public static void main(String[] args) throws IOException {

        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {

                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException e) {
                    e.printStackTrace();
                }

                new ConsoleGUI("Server", 800, 400, false);

            }

        });

        //this should always be running during the life of the program
        gsl.execute();

    }

    static class GameServerLoop extends SwingWorker<Void, Void> {

        @Override
        protected Void doInBackground() {
            System.out.println("1");
            while (true) {
                while (online.get()) {
                    System.out.println("2");
                }
            }
        }

    }

}

一切正常,一个错误.使用该System.out.println()方法以处理速度(while循环)运行此程序将使程序有些 - 没有响应.单击停止按钮将起作用..最终.由于大量的System.out.println()呼叫,似乎所有东西都备份了.

Answer 1

所以你不完整的例子留下了很多未回答的问题,基本上就是这样的......

import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.net.ServerSocket;
import java.util.concurrent.atomic.AtomicBoolean;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class StakeMeServer {

    private ServerSocket socket;
    private Thread t;
    private AtomicBoolean online = new AtomicBoolean(false);

    public static void main(String[] args) throws IOException {
        new StakeMeServer();
    }

    public StakeMeServer() {

        SwingUtilities.invokeLater(new Runnable() {
            try {
                UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
            } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                ex.printStackTrace();
            }

            JFrame frame = new JFrame("Testing");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.add(new TestPane());
            frame.pack();
            frame.setLocationRelativeTo(null);
            frame.setVisible(true);
        });

        open();

        Thread t = new Thread(() -> {
            System.out.println("1");
            while (online.get()) {
                System.out.println("2");
            }
        });
        t.setDaemon(true);
        t.setName("GameServer");
        t.start();
    }

    public void open() {
        System.out.println("Starting Server...");
        online.set(true);
        System.out.println("Server Online");
    }

    public void close() {
        System.out.println("Stopping Server...");
        online.set(false);
        System.out.println("Server Offline");
    }

    public class TestPane extends JPanel {

        private int x = 0;
        private int delta = 4;

        private JLabel state;

        public TestPane() {
            Timer timer = new Timer(40, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    x += delta;
                    if (x + 10 > getWidth()) {
                        x = getWidth() - 10;
                        delta *= -1;
                    } else if (x < 0) {
                        x = 0;
                        delta *= -1;
                    }
                    state.setText(Boolean.toString(online.get()));
                    repaint();
                }
            });
            timer.start();

            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;

            state = new JLabel(Boolean.toString(online.get()));
            add(state, gbc);

            JButton btn = new JButton("Stop");
            btn.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    btn.setEnabled(false);
                    close();
                }
            });
            add(btn, gbc);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            g2d.setColor(Color.RED);
            g2d.fillOval(x, (getHeight() / 2) - 5, 10, 10);
            g2d.dispose();
        }

    }

}

工作得很好.

我使用了一个AtomicBoolean而不是boolean防止线程之间可能的脏读/写,并成为Thread一个守护程序线程,因此应用程序可以关闭,线程不会阻止JVM终止.

就个人而言,我倾向于使用a SwingWorker,因为它提供的功能允许您简单地将更新同步回UI

有关更多详细信息,请查看Swing和Worker Threads中的Concurrency 以及SwingWorker