java中的线程和public void run()方法
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Thread and public void run() method in java
提问by
public Thread thread = new Thread();
public void start() {
running = true;
thread.start();
}
public void run() {
while(running) {
System.out.println("test");
try {
thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
My problem is that the program will not print out "test" nor will it seem to loop despite 'running' being true. Is there a way I can continuously loop in the run method?
我的问题是该程序不会打印出“测试”，也不会在“运行”为真的情况下似乎循环。有没有办法可以在 run 方法中连续循环？
回答by Sotirios Delimanolis
You haven't actually asked run()to be called. All you've done is declare a run()method unrelated to the Thread.
你实际上并没有要求run()被叫。您所做的只是声明一个run()与Thread.
Put your run()method in a Runnableand pass that to the Thread.
将您的run()方法放入 aRunnable并将其传递给Thread.
public Thread thread = new Thread(new Runnable() {
public void run() {
while (running) {
System.out.println("test");
try {
thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
回答by rgettman
The problem appears to be that you aren't running the runmethod that you think you're running in the thread.
问题似乎是您没有运行run您认为在线程中运行的方法。
First, you've created a Threadcalled thread. In your class's startmethod, you set runningto trueand call thread.start(). But that just calls Thread's run()method, which does nothing.
首先，您已经创建了一个Thread名为thread. 在您的类的start方法中，您设置running为true并调用thread.start(). 但这只是调用Thread的run()方法，它什么也不做。
public void run()
If this thread was constructed using a separate Runnable run object, then that Runnable object's run method is called; otherwise, this method does nothing and returns.
公共无效运行（）
如果该线程是使用单独的 Runnable 运行对象构造的，则调用该 Runnable 对象的 run 方法；否则，此方法不执行任何操作并返回。
You aren't calling your own runmethod.
你不是在调用你自己的run方法。
You have created a runmethod. I can't see your class definition here, but I'm assuming that your class implements Runnable. You need to send an instance of your class as an argument to the Thread, by using the Threadconstructor that takes a Runnable. Then the Threadwill know to run your Runnable's run()method.
您已经创建了一个run方法。我在这里看不到你的类定义，但我假设你的类实现了Runnable. 您需要Thread使用Thread带有Runnable. 然后Thread就会知道运行你Runnable的run()方法。
回答by Sage
Well you need to call start()to start the thread. Otherwise neither runningwill be true
nor thread.start()get executed. Well i can guess you were intended to do something like this:
那么你需要调用start()来启动线程。否则既running不会是真的，也不会thread.start()被执行。好吧，我猜你打算做这样的事情：
class MyTask implements Runnable
{
boolean running = false;
public void start() {
running = true;
new Thread(this).start();
}
public void run() {
while(running) {
System.out.println("test");
try {
Thread.sleep(1000);
// you were doing thread.sleep()! sleep is a static function
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args)
{
new MyTask().start();
}
}
