Groovy - 线程生命周期
线程的生命周期
Groovy 中线程的生命周期指的是线程经历的各种状态。例如，线程被创建、启动、运行，然后终止。Thread class 定义了线程的生命周期及其各种状态。
线程生命周期流程图
下图展示了线程的完整生命周期。
线程生命周期的状态
以下是生命周期的各个阶段 −
New − 新线程在其生命周期开始时处于 new 状态。程序启动线程之前，它一直保持在此状态。也称为born thread。
Runnable − 新生线程启动后，线程变为 runnable 状态。此状态的线程被认为正在执行其任务。
Waiting − 有时，线程在等待另一个线程执行任务时会过渡到 waiting 状态。只有当另一个线程通知等待线程继续执行时，该线程才会返回到 runnable 状态。
Timed Waiting − runnable 线程可以进入 timed waiting 状态，持续指定的时间间隔。此状态的线程在时间间隔到期或等待的事件发生时返回到 runnable 状态。
Terminated (Dead) − runnable 线程在完成任务或以其他方式终止时进入 terminated 状态。
示例 - 演示线程状态
在本示例中，我们通过扩展 Thread class 创建了两个线程。我们打印了线程的每个状态。当线程对象被创建时，其状态为 NEW；调用start() method时，状态为 START；调用run() method时，状态为 RUNNING；线程完成 run() 方法的处理后，进入 DEAD 状态。
Example.groovy
class Example {
static void main(String[] args) {
ThreadDemo thread1 = new ThreadDemo( "Thread-1");
ThreadDemo thread2 = new ThreadDemo( "Thread-2");
thread1.start();
thread2.start();
}
}
class ThreadDemo extends Thread {
private Thread t;
private String threadName;
ThreadDemo( String name) {
threadName = name;
System.out.println("Thread: " + threadName + ", " + "State: New"); // 线程：ThreadName，状态：New
}
void run() {
println("Thread: " + threadName + ", " + "State: Running"); // 线程：ThreadName，状态：Running
for(int i = 4; i > 0; i--) {
println("Thread: " + threadName + ", " + i);
}
println("Thread: " + threadName + ", " + "State: Dead"); // 线程：ThreadName，状态：Dead
}
void start () {
println("Thread: " + threadName + ", " + "State: Start"); // 线程：ThreadName，状态：Start
if (t == null) {
t = new Thread (this, threadName);
t.start ();
}
}
}
输出
上述程序产生以下输出 −
Thread: Thread-1, State: New Thread: Thread-2, State: New Thread: Thread-1, State: Start Thread: Thread-2, State: Start Thread: Thread-1, State: Running Thread: Thread-2, State: Running Thread: Thread-2, 4 Thread: Thread-2, 3 Thread: Thread-2, 2 Thread: Thread-2, 1 Thread: Thread-2, State: Dead Thread: Thread-1, 4 Thread: Thread-1, 3 Thread: Thread-1, 2 Thread: Thread-1, 1 Thread: Thread-1, State: Dead
示例 - 检查使用 Thread 类创建的线程状态
在这个示例中，我们使用 sleep() 方法 来引入一些处理延迟，并展示使用线程的并行处理。我们通过扩展 Thread 类创建了两个线程。我们打印了线程的每个状态。当线程对象被创建时，其状态为 NEW；当调用 start() 方法时，状态为 START；当调用 run() 方法时，状态为 RUNNING；如果调用了 sleep()，则线程进入 WAITING 状态；当线程完成 run() 方法的处理后，它进入 DEAD 状态。
Example.groovy
class Example {
static void main(String[] args) {
ThreadDemo thread1 = new ThreadDemo( "Thread-1");
ThreadDemo thread2 = new ThreadDemo( "Thread-2");
thread1.start();
thread2.start();
}
}
class ThreadDemo extends Thread {
private Thread t;
private String threadName;
ThreadDemo( String name) {
threadName = name;
System.out.println("Thread: " + threadName + ", " + "State: New");
}
void run() {
println("Thread: " + threadName + ", " + "State: Running");
try {
for(int i = 4; i > 0; i--) {
println("Thread: " + threadName + ", " + i);
// 让线程休眠一段时间。
println("Thread: " + threadName + ", " + "State: Waiting");
Thread.sleep(50);
}
} catch (InterruptedException e) {
println("Thread " + threadName + " interrupted.");
}
println("Thread: " + threadName + ", " + "State: Dead");
}
void start () {
println("Thread: " + threadName + ", " + "State: Start");
if (t == null) {
t = new Thread (this, threadName);
t.start ();
}
}
}
输出
上述程序产生以下输出 −
Thread: Thread-1, State: New Thread: Thread-2, State: New Thread: Thread-1, State: Start Thread: Thread-2, State: Start Thread: Thread-1, State: Running Thread: Thread-1, 4 Thread: Thread-1, State: Waiting Thread: Thread-2, State: Running Thread: Thread-2, 4 Thread: Thread-2, State: Waiting Thread: Thread-1, 3 Thread: Thread-2, 3 Thread: Thread-2, State: Waiting Thread: Thread-1, State: Waiting Thread: Thread-2, 2 Thread: Thread-1, 2 Thread: Thread-1, State: Waiting Thread: Thread-2, State: Waiting Thread: Thread-2, 1 Thread: Thread-2, State: Waiting Thread: Thread-1, 1 Thread: Thread-1, State: Waiting Thread: Thread-2, State: Dead Thread: Thread-1, State: Dead
示例 - 检查使用 Runnable 接口创建的 Thread 状态
在这个示例中，我们通过实现 Runnable 接口来创建两个线程。我们会打印线程的每个状态。当线程对象被创建时，其状态为 NEW；当调用 start() 方法时，状态为 START；当调用 run() 方法时，状态为 RUNNING；如果调用了 sleep()，则线程进入 WAITING 状态；当线程完成处理 run() 方法时，它进入 DEAD 状态。
Example.groovy
class Example {
static void main(String[] args) {
ThreadDemo thread1 = new ThreadDemo( "Thread-1");
ThreadDemo thread2 = new ThreadDemo( "Thread-2");
thread1.start();
thread2.start();
}
}
class ThreadDemo implements Runnable {
private Thread t;
private String threadName;
ThreadDemo( String name) {
threadName = name;
println("Thread: " + threadName + ", " + "State: New");
}
void run() {
println("Thread: " + threadName + ", " + "State: Running");
try {
for(int i = 4; i > 0; i--) {
println("Thread: " + threadName + ", " + i);
// 让线程休眠一段时间。
println("Thread: " + threadName + ", " + "State: Waiting");
Thread.sleep(50);
}
} catch (InterruptedException e) {
System.out.println("Thread " + threadName + " interrupted.");
}
println("Thread: " + threadName + ", " + "State: Dead");
}
void start () {
println("Thread: " + threadName + ", " + "State: Start");
if (t == null) {
t = new Thread (this, threadName);
t.start ();
}
}
}
输出
Thread: Thread-1, State: New Thread: Thread-2, State: New Thread: Thread-1, State: Start Thread: Thread-2, State: Start Thread: Thread-1, State: Running Thread: Thread-1, 4 Thread: Thread-1, State: Waiting Thread: Thread-2, State: Running Thread: Thread-2, 4 Thread: Thread-2, State: Waiting Thread: Thread-1, 3 Thread: Thread-2, 3 Thread: Thread-2, State: Waiting Thread: Thread-1, State: Waiting Thread: Thread-2, 2 Thread: Thread-1, 2 Thread: Thread-1, State: Waiting Thread: Thread-2, State: Waiting Thread: Thread-2, 1 Thread: Thread-2, State: Waiting Thread: Thread-1, 1 Thread: Thread-1, State: Waiting Thread: Thread-2, State: Dead Thread: Thread-1, State: Dead