執行緒狀態
執行緒有七種狀態
NEW(建立), RUNNABLE(執行階段), BLOCKED(阻斷), WAITING(等待), TIMED_WAITING(長時間等待), TERMINATED(結束);
Runnable
Runnable包含Ready(準備)、Running(執行)。
有可能執行緒執行到一半，cpu資源不足，被強迫讓出yeild cpu資源，就從Running -> Ready。
如果cpu又有資源，執行緒又從 Ready -> Running。
當執行緒呼叫start()方法，狀態從 New -> Ready -> Running。
如果執行緒從sleep()方法中醒來，狀態也會從 TIMED_WAITING -> Ready -> Running。
如果執行緒拿到同步鎖，脫離Blocked阻斷狀態，狀態也會從 BLOCKED -> Ready -> Running。
sleep TimeWaiting
Thread.sleep()
當執行緒在休眠時，此時執行緒是TimeWaiting狀態。
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class T1 extends Thread{
@Override
public void run() {
for (int i = 0; i < 10; i++) {
System.out.println(Thread.currentThread().getName() + " i = " + i);
try {
// 20毫秒休息一次
sleep(20);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
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public class Test5 {
public static void main(String[] args) throws InterruptedException {
T1 t = new T1();
// 設定名字
t.setName("thread1");
System.out.println(t.getName() + " state = " + t.getState());
// 啟動執行緒
t.start();
// 判斷執行緒是否結束了
while (t.getState() != Thread.State.TERMINATED) {
System.out.println(t.getName() + " state = " + t.getState());
// 50毫秒休息一次
Thread.sleep(50);
}
System.out.println(t.getName() + " state = " + t.getState());
}
}
thread1 state = NEW
thread1 state = RUNNABLE
thread1 i = 0
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 i = 1
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 i = 2
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 i = 3
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 state = RUNNABLE
thread1 i = 4
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 i = 5
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 i = 6
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 i = 7
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 i = 8
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 i = 9
thread1 state = TIMED_WAITING
thread1 state = TIMED_WAITING
thread1 state = TERMINATED
由執行結果可以發現，thread1從NEW -> RUNNABLE -> TIMED_WAITING -> TERMINATED的過程。
synchronized Blocked
當執行緒在同步(synchronized)區塊或同步方法的「外面」，此時執行緒是阻斷狀態。
join Waiting
當有其它執行緒插隊，此時執行緒變成Waiting或TimeWaiting狀態，等待其它執行緒執行完畢，狀態才會變成RUNNABLE。
wait Waiting
Thread.wait()
當執行緒在等待wait()，此時執行緒變成Waiting或TimeWaiting狀態。