Java 教程

Java 控制語句

面向物件程式設計

Java 內建類

Java 檔案處理

Java 錯誤和異常

Java 多執行緒

Java 同步

Java 網路程式設計

Java 集合

Java 介面

Java 資料結構

Java 集合演算法

高階 Java

Java 雜項

Java APIs 和框架

Java 類引用

Java 有用資源

Java - 執行緒生命週期

上一頁
下一頁

Java中執行緒的生命週期

Java 中執行緒的生命週期是指執行緒經歷的各種狀態。例如，執行緒誕生、啟動、執行，然後死亡。Thread 類定義了執行緒的生命週期和各種狀態。

Java 執行緒生命週期流程圖

下圖顯示了執行緒的完整生命週期。

Java Thread Life Cycle

Java中執行緒生命週期的狀態

以下是生命週期的階段：

  • 新建 - 新執行緒從新建狀態開始其生命週期。它保持在此狀態，直到程式啟動執行緒。它也稱為新生執行緒。

  • 可執行 - 新生執行緒啟動後，執行緒變為可執行狀態。處於此狀態的執行緒被認為正在執行其任務。

  • 等待 - 有時，當執行緒等待另一個執行緒執行任務時，執行緒會轉換到等待狀態。只有當另一個執行緒發出訊號讓等待執行緒繼續執行時，執行緒才會轉換回可執行狀態。

  • 計時等待 - 可執行執行緒可以進入計時等待狀態，持續指定的間隔時間。處於此狀態的執行緒在其時間間隔到期或其等待的事件發生時轉換回可執行狀態。

  • 終止（死亡） - 可執行執行緒在完成其任務或以其他方式終止時進入終止狀態。

演示執行緒狀態的 Java 示例

在這個例子中，我們透過擴充套件 Thread 類來建立兩個執行緒。我們列印執行緒的每個狀態。當建立執行緒物件時，其狀態為 NEW；當呼叫start() 方法時，狀態為 START；當呼叫run() 方法時，狀態為 RUNNING；當執行緒完成 run() 方法的處理後，它進入 DEAD 狀態。

package com.tutorialspoint;
class ThreadDemo extends Thread {
   private Thread t;
   private String threadName;
   ThreadDemo( String name) {
      threadName = name;
      System.out.println("Thread: " + threadName + ", " + "State: New");
   }
   public void run() {
      System.out.println("Thread: " + threadName + ", " + "State: Running");
      for(int i = 4; i > 0; i--) {
         System.out.println("Thread: " + threadName + ", " + i);
      }
      System.out.println("Thread: " + threadName + ", " + "State: Dead");
   }
   public void start () {
      System.out.println("Thread: " + threadName + ", " + "State: Start");
      if (t == null) {
         t = new Thread (this, threadName);
         t.start ();
      }
   }
}
public class TestThread {
   public static void main(String args[]) {
      ThreadDemo thread1 = new ThreadDemo( "Thread-1");
      ThreadDemo thread2 = new ThreadDemo( "Thread-2");
      thread1.start();
      thread2.start();
   }   
}

輸出

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

更多關於執行緒生命週期和狀態的示例

示例 1

在這個例子中，我們使用sleep() 方法來引入一些處理延遲，並展示使用執行緒的並行處理。我們透過擴充套件 Thread 類來建立兩個執行緒。我們列印執行緒的每個狀態。當建立執行緒物件時，其狀態為 NEW；當呼叫 start() 方法時，狀態為 START；當呼叫 run() 方法時，狀態為 RUNNING；如果呼叫 sleep()，則執行緒進入 WAITING 狀態；當執行緒完成 run() 方法的處理後，它進入 DEAD 狀態。

package com.tutorialspoint;
class ThreadDemo extends Thread {
   private Thread t;
   private String threadName;
   ThreadDemo( String name) {
      threadName = name;
      System.out.println("Thread: " + threadName + ", " + "State: New");
   }
   public void run() {
      System.out.println("Thread: " + threadName + ", " + "State: Running");
      try {
         for(int i = 4; i > 0; i--) {
            System.out.println("Thread: " + threadName + ", " + i);
            // Let the thread sleep for a while.
            System.out.println("Thread: " + threadName + ", " + "State: Waiting");
            Thread.sleep(50);
         }
      } catch (InterruptedException e) {
         System.out.println("Thread " +  threadName + " interrupted.");
      }
      System.out.println("Thread: " + threadName + ", " + "State: Dead");
   }

   public void start () {
      System.out.println("Thread: " + threadName + ", " + "State: Start");
      if (t == null) {
         t = new Thread (this, threadName);
         t.start ();
      }
   }
}
public class TestThread {
   public static void main(String args[]) {
      ThreadDemo thread1 = new ThreadDemo( "Thread-1");
      ThreadDemo thread2 = new ThreadDemo( "Thread-2");
      thread1.start();
      thread2.start();
   }   
}

輸出

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 2

在這個例子中，我們透過實現 Runnable 類來建立兩個執行緒。我們列印執行緒的每個狀態。當建立執行緒物件時，其狀態為 NEW；當呼叫 start() 方法時，狀態為 START；當呼叫 run() 方法時，狀態為 RUNNING；如果呼叫 sleep()，則執行緒進入 WAITING 狀態；當執行緒完成 run() 方法的處理後，它進入 DEAD 狀態。

package com.tutorialspoint;
class ThreadDemo implements Runnable {
   private Thread t;
   private String threadName;
   ThreadDemo( String name) {
      threadName = name;
      System.out.println("Thread: " + threadName + ", " + "State: New");
   }
   public void run() {
      System.out.println("Thread: " + threadName + ", " + "State: Running");
      try {
         for(int i = 4; i > 0; i--) {
            System.out.println("Thread: " + threadName + ", " + i);
            // Let the thread sleep for a while.
            System.out.println("Thread: " + threadName + ", " + "State: Waiting");
            Thread.sleep(50);
         }
      } catch (InterruptedException e) {
         System.out.println("Thread " +  threadName + " interrupted.");
      }
      System.out.println("Thread: " + threadName + ", " + "State: Dead");
   }

   public void start () {
      System.out.println("Thread: " + threadName + ", " + "State: Start");
      if (t == null) {
         t = new Thread (this, threadName);
         t.start ();
      }
   }
}
public class TestThread {
   public static void main(String args[]) {
      ThreadDemo thread1 = new ThreadDemo( "Thread-1");
      ThreadDemo thread2 = new ThreadDemo( "Thread-2");
      thread1.start();
      thread2.start();
   }   
}

輸出

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
列印頁面
上一頁
下一頁
廣告