作者SST2000 (BMW 428i)
看板java
標題[問題] 關於JAVA synchronized的問題?
時間Mon May 11 08:23:56 2020
請問各位,下面這個範例程式為什麼輸出只會有線程0執行??
ackage Thread02;
public class main {
public static void main(String[] args) {
Mythread02 T2=new Mythread02();
Thread t1=new Thread(T2);
Thread t2=new Thread(T2);
Thread t3=new Thread(T2);
t1.start();
t2.start();
t3.start();
}
下面是宣告的class
package Thread02;
public class Mythread02 implements Runnable {
private int number=100;
public void run() {
synchronized (this) {
try {
Thread.sleep(100);
//---------------------------------------------------------------//
while (true) {
if (number > 0) {
System.out.println("This is Mythread02 " +
Thread.currentThread().getName() + "---" + number--);
} else {
break;
}
}
//---------------------------------------------------------------//]
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
----------------------------下面是輸出結果-------------------------
This is Mythread02 Thread-0---100
This is Mythread02 Thread-0---99
This is Mythread02 Thread-0---98
This is Mythread02 Thread-0---97
This is Mythread02 Thread-0---96
This is Mythread02 Thread-0---95
This is Mythread02 Thread-0---94
This is Mythread02 Thread-0---93
This is Mythread02 Thread-0---92
This is Mythread02 Thread-0---91
This is Mythread02 Thread-0---90
This is Mythread02 Thread-0---89
This is Mythread02 Thread-0---88
This is Mythread02 Thread-0---87
This is Mythread02 Thread-0---86
This is Mythread02 Thread-0---85
This is Mythread02 Thread-0---84
This is Mythread02 Thread-0---83
This is Mythread02 Thread-0---82
This is Mythread02 Thread-0---81
This is Mythread02 Thread-0---80
This is Mythread02 Thread-0---79
This is Mythread02 Thread-0---78
This is Mythread02 Thread-0---77
This is Mythread02 Thread-0---76
This is Mythread02 Thread-0---75
This is Mythread02 Thread-0---74
This is Mythread02 Thread-0---73
This is Mythread02 Thread-0---72
This is Mythread02 Thread-0---71
This is Mythread02 Thread-0---70
This is Mythread02 Thread-0---69
This is Mythread02 Thread-0---68
This is Mythread02 Thread-0---67
This is Mythread02 Thread-0---66
This is Mythread02 Thread-0---65
This is Mythread02 Thread-0---64
This is Mythread02 Thread-0---63
This is Mythread02 Thread-0---62
This is Mythread02 Thread-0---61
This is Mythread02 Thread-0---60
This is Mythread02 Thread-0---59
This is Mythread02 Thread-0---58
This is Mythread02 Thread-0---57
This is Mythread02 Thread-0---56
This is Mythread02 Thread-0---55
This is Mythread02 Thread-0---54
This is Mythread02 Thread-0---53
This is Mythread02 Thread-0---52
This is Mythread02 Thread-0---51
This is Mythread02 Thread-0---50
This is Mythread02 Thread-0---49
This is Mythread02 Thread-0---48
This is Mythread02 Thread-0---47
This is Mythread02 Thread-0---46
This is Mythread02 Thread-0---45
This is Mythread02 Thread-0---44
This is Mythread02 Thread-0---43
This is Mythread02 Thread-0---42
This is Mythread02 Thread-0---41
This is Mythread02 Thread-0---40
This is Mythread02 Thread-0---39
This is Mythread02 Thread-0---38
This is Mythread02 Thread-0---37
This is Mythread02 Thread-0---36
This is Mythread02 Thread-0---35
This is Mythread02 Thread-0---34
This is Mythread02 Thread-0---33
This is Mythread02 Thread-0---32
This is Mythread02 Thread-0---31
This is Mythread02 Thread-0---30
This is Mythread02 Thread-0---29
This is Mythread02 Thread-0---28
This is Mythread02 Thread-0---27
This is Mythread02 Thread-0---26
This is Mythread02 Thread-0---25
This is Mythread02 Thread-0---24
This is Mythread02 Thread-0---23
This is Mythread02 Thread-0---22
This is Mythread02 Thread-0---21
This is Mythread02 Thread-0---20
This is Mythread02 Thread-0---19
This is Mythread02 Thread-0---18
This is Mythread02 Thread-0---17
This is Mythread02 Thread-0---16
This is Mythread02 Thread-0---15
This is Mythread02 Thread-0---14
This is Mythread02 Thread-0---13
This is Mythread02 Thread-0---12
This is Mythread02 Thread-0---11
This is Mythread02 Thread-0---10
This is Mythread02 Thread-0---9
This is Mythread02 Thread-0---8
This is Mythread02 Thread-0---7
This is Mythread02 Thread-0---6
This is Mythread02 Thread-0---5
This is Mythread02 Thread-0---4
This is Mythread02 Thread-0---3
This is Mythread02 Thread-0---2
This is Mythread02 Thread-0---1
--
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1F：→ charlie0275: 在 main 主執行緒加上sleep多等幾秒看看 05/11 10:02
2F：→ LZN: 因為synchronized (this)的關係 05/11 11:34
3F：→ ssccg: 在synchronized裡面放sleep並不會把lock釋放 05/11 14:09
4F：→ ssccg: 另外以你的寫法是搶到的Thread就會一次跑完，如果你是要模 05/11 14:18
5F：→ ssccg: 擬每個數字都重搶一次，Thread中斷應該放在迴圈裡吧 05/11 14:19
6F：→ ssccg: while (true) { 05/11 14:23
7F：→ ssccg: synchronized (this) { 05/11 14:23
8F：→ ssccg: if (...) {...} else { break; } 05/11 14:24
9F：→ ssccg: } 05/11 14:24
10F：→ ssccg: Thread.sleep(100); 05/11 14:24
11F：→ ssccg: } 05/11 14:24
12F：→ ssccg: 我猜你想做的效果是這樣 05/11 14:26
13F：→ ssccg: 如果一定要synchonized在外面，要用wait/notify來控制lock 05/11 14:27