线程停止的方法详解

线程停止的方法

总结：

1.设置标志位(无法处理线程阻塞时停止的问题)

2.调用Thread类提供的stop方法强行关闭线程。（本方法现在已经不推荐使用,因为会产生不完整数据）

3.调用Thread类提供的interrupt():

（1）若线程中没有使用类似sleep/wait/join时，调用此线程对象的interrupt方法并不会真正中断线程，只是简单地将线程的状态置为interrupt而已，我们可以根据此状态来进一步确定如何处理线程。

Thread类提供的public boolean isInterrupted()可以检测当前线程状态是否为中断状态

（2）若线程中调用了阻塞线程的方法如:sleep()、wait()、join()此时再调用线程的interrupt方法时会抛出异常InterruptedException,同时将线程状态还原(isInterrupted = false)，此时我们想让它停止，直接在catch块中return。

1.设置标志位：

（无法处理线程阻塞时停止的问题 实例1）

代码：

class ThreadShutDown implements Runnable{ private boolean flag = true; public void setFlag(boolean flag){ this.flag = flag; } @Override public void run() { int i=0; while(flag){ System.out.println(Thread.currentThread().getName()+","+i++); } System.out.println("线程停止"); } } public class ThreadStop { public static void main(String[] args) throws InterruptedException { ThreadShutDown threadShutDown = new ThreadShutDown(); Thread thread = new Thread(threadShutDown); thread.start(); Thread.sleep(1000);//运行1秒后将其关掉 threadShutDown.setFlag(false); } }

运行结果：

代码：实例1

class ThreadShutDown2 implements Runnable{ private boolean flag = true; public void setFlag(boolean flag){ this.flag = flag; } @Override public void run() { int i=0; while(flag){ try { Thread.sleep(200); } catch (InterruptedException e) { e.printStackTrace(); } } System.out.println("线程停止"); } } public class ThreadStop { public static void main(String[] args) throws InterruptedException { ThreadShutDown2 threadShutDown = new ThreadShutDown2(); Thread thread = new Thread(threadShutDown); thread.start(); thread.sleep(200); threadShutDown.setFlag(true); } }

结果：

2.调用Thread类提供的stop方法强行关闭线程：

（本方法现在已经不推荐使用，可能会产生不完整数据，如下面中的“线程停止”并没有输出）

代码：

public class ThreadStop { public static void main(String[] args) throws InterruptedException { ThreadShutDown threadShutDown = new ThreadShutDown(); Thread thread = new Thread(threadShutDown); thread.start(); Thread.sleep(1000); thread.stop();//调用Thread类提供的stop方法强行关闭线程。 } }

运行结果：

3.调用Thread类提供的interrupt()：

（1）若线程中没有使用类似sleep/wait/join时，调用此线程对象的interrupt方法并不会真正中断线程，只是简单地将线程的状态置为interrupt而已（实例2），我们可以根据此状态来进一步确定如何处理线程（实例3）。

Thread类提供的public boolean isInterrupted()可以检测当前线程状态是否为中断状态。

代码：实例2

class ThreadShutDown2 implements Runnable{ private boolean flag = true; public void setFlag(boolean flag){ this.flag = flag; } @Override public void run() { int i=0; while(flag){ boolean bool = Thread.currentThread().isInterrupted(); System.out.println("当前线程状态为："+bool); System.out.println(Thread.currentThread().getName()+","+i++); } System.out.println("线程停止"); } } public class ThreadStop { public static void main(String[] args) throws InterruptedException { ThreadShutDown2 threadShutDown = new ThreadShutDown2(); Thread thread = new Thread(threadShutDown); thread.start(); Thread.sleep(1000); thread.interrupt(); } }

结果：

只是将线程的状态置为interrupt而已，并没有停止

代码：实例3

class ThreadShutDown2 implements Runnable{ private boolean flag = true; public void setFlag(boolean flag){ this.flag = flag; } @Override public void run() { int i=0; while(flag){ boolean bool = Thread.currentThread().isInterrupted(); if(bool){ System.out.println("线程已被中断"); return; } System.out.println("当前线程状态为："+bool); System.out.println(Thread.currentThread().getName()+","+i++); } System.out.println("线程停止"); } } public class ThreadStop { public static void main(String[] args) throws InterruptedException { ThreadShutDown2 threadShutDown = new ThreadShutDown2(); Thread thread = new Thread(threadShutDown); thread.start(); Thread.sleep(1000); thread.interrupt(); } }

结果：

此时又与方法一类似了。

（2）若线程中调用了阻塞线程的方法如:sleep()、wait()、join()此时再调用线程的interrupt方法时会抛出异常InterruptedException,同时将线程状态还原(isInterrupted = false)  （实例4）

代码：实例4

class ThreadShutDown2 implements Runnable{ private boolean flag = true; public void setFlag(boolean flag){ this.flag = flag; } @Override public void run() { int i=0; while(flag){ try { Thread.sleep(200); boolean bool = Thread.currentThread().isInterrupted(); if(bool){ System.out.println("线程已被中断"); return; } System.out.println("当前线程状态为："+bool); System.out.println(Thread.currentThread().getName()+","+i++); } catch (InterruptedException e) { boolean bool = Thread.currentThread().isInterrupted(); if(bool){ System.out.println("线程已被中断"); return; } System.out.println("当前线程状态为："+bool); System.out.println(Thread.currentThread().getName()+","+i++); e.printStackTrace(); } } System.out.println("线程停止"); } } public class ThreadStop { public static void main(String[] args) throws InterruptedException { ThreadShutDown2 threadShutDown = new ThreadShutDown2(); Thread thread = new Thread(threadShutDown); thread.start(); thread.interrupt(); } }

结果：

此时我们想让它停止，直接在catch块中return；

class ThreadShutDown2 implements Runnable{ private boolean flag = true; public void setFlag(boolean flag){ this.flag = flag; } @Override public void run() { int i=0; while(flag){ try { Thread.sleep(200); boolean bool = Thread.currentThread().isInterrupted(); if(bool){ System.out.println("线程已被中断"); return; } System.out.println("当前线程状态为："+bool); System.out.println(Thread.currentThread().getName()+","+i++); } catch (InterruptedException e) { System.out.println("抛出中断异常"); return ; } } System.out.println("线程停止"); } } public class ThreadStop { public static void main(String[] args) throws InterruptedException { ThreadShutDown2 threadShutDown = new ThreadShutDown2(); Thread thread = new Thread(threadShutDown); thread.start(); thread.sleep(1000); thread.interrupt(); } }

结果：