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java多线程实现(java多线程简单实例)
导语：java多线程，用Java实现线程状态
在Java中，要获取线程的当前状态，请使用Thread.getState（）方法获取线程的当前状态。Java提供了java.lang.Thread.State类，它定义了线程状态的ENUM常量，如下所示：
常量类型：NEW声明：public static final Thread.State NEW描述：尚未启动的线程的线程状态。常量类型： Runnable
声明：public static final Thread.State RUNNABLE描述：可运行线程的线程状态。处于可运行状态的线程正在Java虚拟机中执行，但它可能正在等待来自操作系统的其他资源，例如处理器。常量类型：BLOCKED
声明：public static final Thread.State BLOCKED描述：线程阻塞等待监视器锁定的线程状态。处于阻塞状态的线程正在等待监视器锁定以在调用Object.wait（）之后输入同步块/方法或重新输入同步块/方法。常量类型：WAITING
声明：public static final Thread.State WAITING描述：等待线程的线程状态。等待线程的线程状态。由于调用以下方法之一，线程处于等待状态：Object.wait with no timeoutThread.join with no timeoutLockSupport.park处于等待状态的线程正在等待另一个线程执行特定操作。常量类型：Time waiting
声明：public static final Thread.State TIMED_WAITING描述：具有指定等待时间的等待线程的线程状态。由于在指定的正等待时间内调用以下方法之一，线程处于定时等待状态：Thread.sleepObject.wait with timeoutThread.join with timeoutLockSupport.parkNanosLockSupport.parkUntil常量类型：Terminated
声明：public static final Thread.State TERMINATED描述：已终止线程的线程状态。线程已完成执行。
// Java program to demonstrate thread statesclass thread implements Runnable{ public void run() { // moving thread2 to timed waiting state try { Thread.sleep(1500); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(1500); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("State of thread1 while it called join() method on thread2 -"+ Test.thread1.getState()); try { Thread.sleep(200); } catch (InterruptedException e) { e.printStackTrace(); } }} public class Test implements Runnable{ public static Thread thread1; public static Test obj; public static void main(String[] args) { obj = new Test(); thread1 = new Thread(obj); // thread1 created and is currently in the NEW state. System.out.println("State of thread1 after creating it - " + thread1.getState()); thread1.start(); // thread1 moved to Runnable state System.out.println("State of thread1 after calling .start() method on it - " + thread1.getState()); } public void run() { thread myThread = new thread(); Thread thread2 = new Thread(myThread); // thread1 created and is currently in the NEW state. System.out.println("State of thread2 after creating it - "+ thread2.getState()); thread2.start(); // thread2 moved to Runnable state System.out.println("State of thread2 after calling .start() method on it - " + thread2.getState()); // moving thread1 to timed waiting state try { //moving thread2 to timed waiting state Thread.sleep(200); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("State of thread2 after calling .sleep() method on it - "+ thread2.getState() ); try { // waiting for thread2 to die thread2.join(); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("State of thread2 when it has finished it's execution - " + thread2.getState()); } }输出：
State of thread1 after creating it - NEWState of thread1 after calling .start() method on it - RUNNABLEState of thread2 after creating it - NEWState of thread2 after calling .start() method on it - RUNNABLEState of thread2 after calling .sleep() method on it - TIMED_WAITINGState of thread1 while it called join() method on thread2 -WAITINGState of thread2 when it has finished it's execution - TERMINATED
说明：创建新线程时，线程处于NEW状态。在线程上调用.start（）方法时，线程调度程序将其移动到Runnable状态。每当在线程实例上调用join（）方法时，执行该语句的当前线程将等待此线程移动到Terminated状态。因此，在控制台上打印最终语句之前，程序调用thread2上的join（），使thread1等待，而thread2完成其执行并移至Terminated状态。thread1进入等待状态，因为它等待thread2完成它的执行，因为它在thread2上调用了join。
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