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Runnable问题一个问题5

由于平时开发中很少用到多线程，可是最近面试总是问多线程，我答不上来，很是尴尬，自己看了这点方面的知识，有个问题请教下大家：直接上代码了
代码：
public class RunnableTest2 implements Runnable {
public void run() {
for (int i = 0; i < 100; i++) {
System.out.println(Thread.currentThread().getName() + " for loop "
+ i);
}
synchronized (this) {
for (int i = 0; i < 100; i++) {
if (i == 50) {
System.out.println("当前线程被睡眠"+Thread.currentThread().getName());
try {
Thread.currentThread().sleep(5000);

} catch (Exception e) {
e.printStackTrace();
}
}
System.out.println(Thread.currentThread().getName()
+ "synchronized for loop " + i);
}
}
}

public static void main(String[] args) {
RunnableTest2 r1 = new RunnableTest2();
RunnableTest2 r2 = new RunnableTest2();
Thread t1 = new Thread(r1);
Thread t2 = new Thread(r2);
t1.start();
t2.start();
}
}
print结果：
Thread-0 for loop 0
Thread-0 for loop 1
Thread-1 for loop 0
Thread-1 for loop 1
Thread-1 for loop 2
Thread-1 for loop 3
Thread-1 for loop 4
Thread-1 for loop 5
Thread-1 for loop 6
Thread-1 for loop 7
Thread-1 for loop 8
Thread-1 for loop 9
Thread-1 for loop 10
Thread-1 for loop 11
Thread-1 for loop 12
Thread-1 for loop 13
Thread-1 for loop 14
Thread-1 for loop 15
Thread-1 for loop 16
Thread-1 for loop 17
Thread-1 for loop 18
Thread-1 for loop 19
Thread-1 for loop 20
Thread-1 for loop 21
Thread-1 for loop 22
Thread-1 for loop 23
Thread-1 for loop 24
Thread-1 for loop 25
Thread-1 for loop 26
Thread-1 for loop 27
Thread-1 for loop 28
Thread-1 for loop 29
Thread-1 for loop 30
Thread-1 for loop 31
Thread-1 for loop 32
Thread-1 for loop 33
Thread-1 for loop 34
Thread-1 for loop 35
Thread-1 for loop 36
Thread-1 for loop 37
Thread-1 for loop 38
Thread-1 for loop 39
Thread-1 for loop 40
Thread-1 for loop 41
Thread-1 for loop 42
Thread-1 for loop 43
Thread-1 for loop 44
Thread-1 for loop 45
Thread-1 for loop 46
Thread-1 for loop 47
Thread-1 for loop 48
Thread-1 for loop 49
Thread-1 for loop 50
Thread-1 for loop 51
Thread-1 for loop 52
Thread-1 for loop 53
Thread-1 for loop 54
Thread-1 for loop 55
Thread-1 for loop 56
Thread-1 for loop 57
Thread-1 for loop 58
Thread-1 for loop 59
Thread-1 for loop 60
Thread-1 for loop 61
Thread-1 for loop 62
Thread-1 for loop 63
Thread-1 for loop 64
Thread-1 for loop 65
Thread-1 for loop 66
Thread-1 for loop 67
Thread-1 for loop 68
Thread-1 for loop 69
Thread-1 for loop 70
Thread-1 for loop 71
Thread-1 for loop 72
Thread-1 for loop 73
Thread-1 for loop 74
Thread-1 for loop 75
Thread-1 for loop 76
Thread-1 for loop 77
Thread-1 for loop 78
Thread-1 for loop 79
Thread-1 for loop 80
Thread-1 for loop 81
Thread-1 for loop 82
Thread-1 for loop 83
Thread-1 for loop 84
Thread-1 for loop 85
Thread-1 for loop 86
Thread-1 for loop 87
Thread-1 for loop 88
Thread-1 for loop 89
Thread-1 for loop 90
Thread-1 for loop 91
Thread-1 for loop 92
Thread-1 for loop 93
Thread-1 for loop 94
Thread-1 for loop 95
Thread-1 for loop 96
Thread-1 for loop 97
Thread-1 for loop 98
Thread-1 for loop 99
Thread-1synchronized for loop 0
Thread-1synchronized for loop 1
Thread-1synchronized for loop 2
Thread-1synchronized for loop 3
Thread-1synchronized for loop 4
Thread-1synchronized for loop 5
Thread-1synchronized for loop 6
Thread-1synchronized for loop 7
Thread-1synchronized for loop 8
Thread-1synchronized for loop 9
Thread-1synchronized for loop 10
Thread-1synchronized for loop 11
Thread-1synchronized for loop 12
Thread-1synchronized for loop 13
Thread-1synchronized for loop 14
Thread-1synchronized for loop 15
Thread-1synchronized for loop 16
Thread-1synchronized for loop 17
Thread-1synchronized for loop 18
Thread-1synchronized for loop 19
Thread-1synchronized for loop 20
Thread-1synchronized for loop 21
Thread-1synchronized for loop 22
Thread-1synchronized for loop 23
Thread-1synchronized for loop 24
Thread-1synchronized for loop 25
Thread-1synchronized for loop 26
Thread-1synchronized for loop 27
Thread-1synchronized for loop 28
Thread-1synchronized for loop 29
Thread-1synchronized for loop 30
Thread-1synchronized for loop 31
Thread-1synchronized for loop 32
Thread-1synchronized for loop 33
Thread-1synchronized for loop 34
Thread-1synchronized for loop 35
Thread-1synchronized for loop 36
Thread-1synchronized for loop 37
Thread-1synchronized for loop 38
Thread-1synchronized for loop 39
Thread-1synchronized for loop 40
Thread-1synchronized for loop 41
Thread-1synchronized for loop 42
Thread-1synchronized for loop 43
Thread-1synchronized for loop 44
Thread-1synchronized for loop 45
Thread-1synchronized for loop 46
Thread-1synchronized for loop 47
Thread-1synchronized for loop 48
Thread-1synchronized for loop 49
当前线程被睡眠Thread-1
Thread-0 for loop 2
Thread-0 for loop 3
Thread-0 for loop 4
Thread-0 for loop 5
Thread-0 for loop 6
Thread-0 for loop 7
Thread-0 for loop 8
Thread-0 for loop 9
Thread-0 for loop 10
Thread-0 for loop 11
Thread-0 for loop 12
Thread-0 for loop 13
Thread-0 for loop 14
Thread-0 for loop 15
Thread-0 for loop 16
Thread-0 for loop 17
Thread-0 for loop 18
Thread-0 for loop 19
Thread-0 for loop 20
Thread-0 for loop 21
Thread-0 for loop 22
Thread-0 for loop 23
Thread-0 for loop 24
Thread-0 for loop 25
Thread-0 for loop 26
Thread-0 for loop 27
Thread-0 for loop 28
Thread-0 for loop 29
Thread-0 for loop 30
Thread-0 for loop 31
Thread-0 for loop 32
Thread-0 for loop 33
Thread-0 for loop 34
Thread-0 for loop 35
Thread-0 for loop 36
Thread-0 for loop 37
Thread-0 for loop 38
Thread-0 for loop 39
Thread-0 for loop 40
Thread-0 for loop 41
Thread-0 for loop 42
Thread-0 for loop 43
Thread-0 for loop 44
Thread-0 for loop 45
Thread-0 for loop 46
Thread-0 for loop 47
Thread-0 for loop 48
Thread-0 for loop 49
Thread-0 for loop 50
Thread-0 for loop 51
Thread-0 for loop 52
Thread-0 for loop 53
Thread-0 for loop 54
Thread-0 for loop 55
Thread-0 for loop 56
Thread-0 for loop 57
Thread-0 for loop 58
Thread-0 for loop 59
Thread-0 for loop 60
Thread-0 for loop 61
Thread-0 for loop 62
Thread-0 for loop 63
Thread-0 for loop 64
Thread-0 for loop 65
Thread-0 for loop 66
Thread-0 for loop 67
Thread-0 for loop 68
Thread-0 for loop 69
Thread-0 for loop 70
Thread-0 for loop 71
Thread-0 for loop 72
Thread-0 for loop 73
Thread-0 for loop 74
Thread-0 for loop 75
Thread-0 for loop 76
Thread-0 for loop 77
Thread-0 for loop 78
Thread-0 for loop 79
Thread-0 for loop 80
Thread-0 for loop 81
Thread-0 for loop 82
Thread-0 for loop 83
Thread-0 for loop 84
Thread-0 for loop 85
Thread-0 for loop 86
Thread-0 for loop 87
Thread-0 for loop 88
Thread-0 for loop 89
Thread-0 for loop 90
Thread-0 for loop 91
Thread-0 for loop 92
Thread-0 for loop 93
Thread-0 for loop 94
Thread-0 for loop 95
Thread-0 for loop 96
Thread-0 for loop 97
Thread-0 for loop 98
Thread-0 for loop 99
Thread-0synchronized for loop 0
Thread-0synchronized for loop 1
Thread-0synchronized for loop 2
Thread-0synchronized for loop 3
Thread-0synchronized for loop 4
Thread-0synchronized for loop 5
Thread-0synchronized for loop 6
Thread-0synchronized for loop 7
Thread-0synchronized for loop 8
Thread-0synchronized for loop 9
Thread-0synchronized for loop 10
Thread-0synchronized for loop 11
Thread-0synchronized for loop 12
Thread-0synchronized for loop 13
Thread-0synchronized for loop 14
Thread-0synchronized for loop 15
Thread-0synchronized for loop 16
Thread-0synchronized for loop 17
Thread-0synchronized for loop 18
Thread-0synchronized for loop 19
Thread-0synchronized for loop 20
Thread-0synchronized for loop 21
Thread-0synchronized for loop 22
Thread-0synchronized for loop 23
Thread-0synchronized for loop 24
Thread-0synchronized for loop 25
Thread-0synchronized for loop 26
Thread-0synchronized for loop 27
Thread-0synchronized for loop 28
Thread-0synchronized for loop 29
Thread-0synchronized for loop 30
Thread-0synchronized for loop 31
Thread-0synchronized for loop 32
Thread-0synchronized for loop 33
Thread-0synchronized for loop 34
Thread-0synchronized for loop 35
Thread-0synchronized for loop 36
Thread-0synchronized for loop 37
Thread-0synchronized for loop 38
Thread-0synchronized for loop 39
Thread-0synchronized for loop 40
Thread-0synchronized for loop 41
Thread-0synchronized for loop 42
Thread-0synchronized for loop 43
Thread-0synchronized for loop 44
Thread-0synchronized for loop 45
Thread-0synchronized for loop 46
Thread-0synchronized for loop 47
Thread-0synchronized for loop 48
Thread-0synchronized for loop 49
当前线程被睡眠Thread-0
Thread-1synchronized for loop 50
Thread-1synchronized for loop 51
Thread-1synchronized for loop 52
Thread-1synchronized for loop 53
Thread-1synchronized for loop 54
Thread-1synchronized for loop 55
Thread-1synchronized for loop 56
Thread-1synchronized for loop 57
Thread-1synchronized for loop 58
Thread-1synchronized for loop 59
Thread-1synchronized for loop 60
Thread-1synchronized for loop 61
Thread-1synchronized for loop 62
Thread-1synchronized for loop 63
Thread-1synchronized for loop 64
Thread-1synchronized for loop 65
Thread-1synchronized for loop 66
Thread-1synchronized for loop 67
Thread-1synchronized for loop 68
Thread-1synchronized for loop 69
Thread-1synchronized for loop 70
Thread-1synchronized for loop 71
Thread-1synchronized for loop 72
Thread-1synchronized for loop 73
Thread-1synchronized for loop 74
Thread-1synchronized for loop 75
Thread-1synchronized for loop 76
Thread-1synchronized for loop 77
Thread-1synchronized for loop 78
Thread-1synchronized for loop 79
Thread-1synchronized for loop 80
Thread-1synchronized for loop 81
Thread-1synchronized for loop 82
Thread-1synchronized for loop 83
Thread-1synchronized for loop 84
Thread-1synchronized for loop 85
Thread-1synchronized for loop 86
Thread-1synchronized for loop 87
Thread-1synchronized for loop 88
Thread-1synchronized for loop 89
Thread-1synchronized for loop 90
Thread-1synchronized for loop 91
Thread-1synchronized for loop 92
Thread-1synchronized for loop 93
Thread-1synchronized for loop 94
Thread-1synchronized for loop 95
Thread-1synchronized for loop 96
Thread-1synchronized for loop 97
Thread-1synchronized for loop 98
Thread-1synchronized for loop 99
Thread-0synchronized for loop 50
Thread-0synchronized for loop 51
Thread-0synchronized for loop 52
Thread-0synchronized for loop 53
Thread-0synchronized for loop 54
Thread-0synchronized for loop 55
Thread-0synchronized for loop 56
Thread-0synchronized for loop 57
Thread-0synchronized for loop 58
Thread-0synchronized for loop 59
Thread-0synchronized for loop 60
Thread-0synchronized for loop 61
Thread-0synchronized for loop 62
Thread-0synchronized for loop 63
Thread-0synchronized for loop 64
Thread-0synchronized for loop 65
Thread-0synchronized for loop 66
Thread-0synchronized for loop 67
Thread-0synchronized for loop 68
Thread-0synchronized for loop 69
Thread-0synchronized for loop 70
Thread-0synchronized for loop 71
Thread-0synchronized for loop 72
Thread-0synchronized for loop 73
Thread-0synchronized for loop 74
Thread-0synchronized for loop 75
Thread-0synchronized for loop 76
Thread-0synchronized for loop 77
Thread-0synchronized for loop 78
Thread-0synchronized for loop 79
Thread-0synchronized for loop 80
Thread-0synchronized for loop 81
Thread-0synchronized for loop 82
Thread-0synchronized for loop 83
Thread-0synchronized for loop 84
Thread-0synchronized for loop 85
Thread-0synchronized for loop 86
Thread-0synchronized for loop 87
Thread-0synchronized for loop 88
Thread-0synchronized for loop 89
Thread-0synchronized for loop 90
Thread-0synchronized for loop 91
Thread-0synchronized for loop 92
Thread-0synchronized for loop 93
Thread-0synchronized for loop 94
Thread-0synchronized for loop 95
Thread-0synchronized for loop 96
Thread-0synchronized for loop 97
Thread-0synchronized for loop 98
Thread-0synchronized for loop 99
我的理解是：
Thread-1先占用了同步块，跑到50的时候，睡了，让给了Thread-0，Thread-0跑完第一个循环，跑到了第二循环的50的时候也睡了，然后他们都开始等，由于Thread-0是后睡了，所以Thread-1先醒，醒了就跑，跑完了Thread-0跑。
不知道我的理解对不对。
 
2014年5月24日 22:42

2个答案 按时间排序 按投票排序

0 0

采纳的答案

楼主，关于sleep方法，会导致线程睡眠，但是只会让出CPU的时间片，不会让出当前线程的锁的。
另外，你创建的是两个Runnable的对象，在类内部 

synchronized(this) {
  ....
}
//这其中的this即当前使用的对象，在两个不同对象执行同一个方法时，不会达到互斥效果的。


所以，为了实现一个你要的效果可以wait/notify，在一个线程执行过程中使用wait让出拥有的锁，此时notify的执行会让另一个等待锁的线程获取到，并继续执行。

2014年5月25日 09:59
0 0

1.首先sleep（）方法会让当前线程睡眠(停止执行)mills毫秒，线程由运行中的状态进入不可运行状态，睡眠时间过后线程会再进入可运行状态
Thread-1 与Thread-0 他们是片段执行而已 没有说那个一定要先执行完 再执行那个
我把你的循环修改成10了
package cn.com.chinagril.test;

public class Test implements Runnable {
public void run() {
for (int i = 0; i < 10; i++) {
System.out.println(Thread.currentThread().getName() + " for loop "
+ i);
}
synchronized (this) {

for (int i = 0; i < 10; i++) {
if (i == 50) {
System.out.println("当前线程被睡眠"+Thread.currentThread().getName());
try {
Thread.currentThread().sleep(5000);


} catch (Exception e) {
e.printStackTrace();
}
}

System.out.println(Thread.currentThread().getName()
+ "synchronized for loop " + i);
}
}
}

public static void main(String[] args) {
Test r1 = new Test();
Test r2 = new Test();
Thread t1 = new Thread(r1);
Thread t2 = new Thread(r2);
t1.start();
t2.start();
}

}


Thread-0 for loop 0
Thread-1 for loop 0
Thread-0 for loop 1
Thread-1 for loop 1
Thread-0 for loop 2
Thread-1 for loop 2
Thread-0 for loop 3
Thread-1 for loop 3
Thread-0 for loop 4
Thread-1 for loop 4
Thread-1 for loop 5
Thread-1 for loop 6
Thread-1 for loop 7
Thread-1 for loop 8
Thread-0 for loop 5
Thread-0 for loop 6
Thread-1 for loop 9
Thread-0 for loop 7
Thread-1synchronized for loop 0
Thread-0 for loop 8
Thread-1synchronized for loop 1
Thread-0 for loop 9
Thread-1synchronized for loop 2
Thread-0synchronized for loop 0
Thread-1synchronized for loop 3
Thread-0synchronized for loop 1
Thread-1synchronized for loop 4
Thread-0synchronized for loop 2
Thread-1synchronized for loop 5
Thread-0synchronized for loop 3
Thread-1synchronized for loop 6
Thread-0synchronized for loop 4
Thread-1synchronized for loop 7
Thread-1synchronized for loop 8
Thread-0synchronized for loop 5
Thread-1synchronized for loop 9
Thread-0synchronized for loop 6
Thread-0synchronized for loop 7
Thread-0synchronized for loop 8
Thread-0synchronized for loop 9

2014年5月25日 00:41

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