ReadWriteLock和ReentrantLock相比，在读多写少的场景下，性能有很多的提升
1、读读不互斥
2、读写互斥
3、写写互斥
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
package concurrent;
import java.util.Random;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class {
Lock lock = new ReentrantLock();
ReentrantReadWriteLock readWriteLock = new ReentrantReadWriteLock();
Lock readLock = readWriteLock.readLock();
Lock writeLock = readWriteLock.writeLock();
int value = 0;
public int read(Lock lock) {
try {
lock.lock();
Thread.sleep(1 * 1000);
System.out.println("读到的值为 ：" + value);
return value;
} catch (InterruptedException e) {
e.printStackTrace();
return value;
} finally {
lock.unlock();
}
}
public void write(Lock lock, int value) {
try {
lock.lock();
Thread.sleep(1 * 1000);
this.value = value;
System.out.println("写入的值为 ：" + value);
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public static void main(String[] args) {
final ReadWriteLockDemo demo = new ReadWriteLockDemo();
Runnable readRun = new Runnable() {
public void run() {
Lock lock = demo.readLock;
int value = demo.read(lock);
}
};
Runnable writeRun = new Runnable() {
public void run() {
Lock lock = demo.writeLock;
demo.write(lock, new Random().nextInt());
}
};
for (int i = 0; i < 20; i++) {
if (i > 1) {
new Thread(readRun, "" + i).start();
} else {
new Thread(writeRun, "" + i).start();
}
}
}
}
|
近期评论