Question

当我运行程序时，它不会显示“HIIII”。我是新手（有点）所以请不要“讨厌”。我的wait（）语句错了吗？或者我做错了什么？它是ArrayIndexOutOfBounds catch子句吗？请帮忙！

[edit]哦，这是主要方法吗？它什么都不做？ [edit]我知道等待和通知是错误的...请不要提及。

//this is the whole class
import javax.swing.*;
import javax.swing.JOptionPane;
public class none {

static boolean game;
final static boolean on = true;
final static boolean off = false;
static boolean cheatMode;
public static void main(String[] args) {
    game = on;
    boolean tru = true;
    try{
        if(tru = Boolean.parseBoolean(args[0])){
            cheatMode = on;
            System.out.println("Cheats are on.");
        }
        }
        catch(java.lang.ArrayIndexOutOfBoundsException e){
            e.printStackTrace();
            System.out.println("Ignore this error, it's from not running it on the command prompt.");
        }
}



public class console extends Thread{
    public void run(){
        try{
        wait();
        JOptionPane.showMessageDialog(null,"HIIII");
        }
        catch(Exception e){
            e.printStackTrace();
            System.out.println("The console glitched...");
        }
//hiiii
        JOptionPane.showMessageDialog(null,"HIIII");
        }
    public class mainThingy extends Thread{
        public void run() {
        if(game = on)
        notify();
    }
}
    }
}

Answer 1

似乎有几个问题

1) if(tru = Boolean.parseBoolean(args[0])){

以上声明是assignemt而非比较。使用==运算符。

2）应始终从同步块内部调用等待和通知。您的代码似乎没有这样做。

Answer 2

>java none true仅打印Cheats are on。但你的问题是打印Hiii。不是吗？你已经在JOptionPane类的console对话框中得到了它。如果没有初始化它，您如何期望您的程序打印Hiii？为什么你在一个文件中写了两个公共类？当您调用wait和nottify方法时，您也错过了synchronized语句。因此，当您开始线程console和mainThingy时，无论如何都会抛出IllegalMonitorStateException。那么你到底想要做什么呢？

Answer 3

您main方法实际上并未启动任何内容
wait和notify必须synchronized在同一台显示器/锁上
您的两个主题不共享同一个监听/锁定

if (game = on)

mainThingy

if (game == on)

public class TestThread {

    static boolean game;
    final static boolean on = true;
    final static boolean off = false;
    static boolean cheatMode;

    public static void main(String[] args) {
        game = on;
        boolean tru = true;
        try {
            if (args.length > 0) {
                if (tru = Boolean.parseBoolean(args[0])) {
                    cheatMode = on;
                    System.out.println("Cheats are on.");
                }
            }
        } catch (java.lang.ArrayIndexOutOfBoundsException e) {
            e.printStackTrace();
            System.out.println("Ignore this error, it's from not running it on the command prompt.");
        }

        Console con = new Console();
        con.start();

        // Give time for the console thread to get started
        do {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException ex) {
                Logger.getLogger(TestThread.class.getName()).log(Level.SEVERE, null, ex);
            }
        } while (!con.isAlive());

        System.out.println("Start main...");
        Console.MainThingy main = new Console.MainThingy();
        main.start();

    }

    public static class Console extends Thread {

        // A shared lock that our two threads can communicate on...
        public static final Object WAIT_LOCK = new Object();

        public void run() {
            try {
                System.out.println("Waiting...");
                // Must "own" the monitor before we can call wait
                synchronized (WAIT_LOCK) {
                    WAIT_LOCK.wait();
                }
                JOptionPane.showMessageDialog(null, "HIIII");
            } catch (Exception e) {
                e.printStackTrace();
                System.out.println("The console glitched...");
            }
        }

        public static class MainThingy extends Thread {

            public void run() {
                if (game == on) {
                    // Must "own" the monitor before we can call notify
                    synchronized (WAIT_LOCK) {
                        System.out.println("Notify...");
                        WAIT_LOCK.notify();
                    }
                }
            }
        }
    }
}

使用示例更新

{{1}}

Java并发很有趣，但是如果你不小心并且很好地对待它，它会咬你。

阅读Currency in Java

Answer 4

我建议不要使用标准的wait（） - notify（）结构。有更好的方法：Java并发包。

正如您在学习Java的第一步中所做的那样，我建议另外两本书：

catch子句之后的java wait（）语句

4 个答案: