《2021/03/22》多线程编码

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
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
public class ABDemo {
}
class ABPrint {
private boolean flag = false;
public synchronized void printA() {
while (flag) {
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("A");
flag = true;
this.notifyAll();
}
public synchronized void printB() {
while (!flag) {
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("B");
flag = false;
this.notifyAll();
}
public static void main(String[] args) {
ABPrint demo = new ABPrint();
new Thread(() -> {
for (int i = 0; i < 10; i++) {
demo.printA();
}
}, "A").start();
new Thread(() -> {
for (int i = 0; i < 10; i++) {
demo.printB();
}
}, "B").start();
}
}
class BAPrint {
private volatile boolean flag = false;
private Object o = new Object();
public void printA() {
synchronized (o) {
while (flag) {
try {
o.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
flag = true;
System.out.println("A");
o.notify();
}
}
public void printB() {
synchronized (o) {
while (!flag) {
try {
o.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("B");
flag = false;
o.notify();
}
}
public static void main(String[] args) {
BAPrint demo = new BAPrint();
new Thread(() -> {
for (int i = 0; i < 10; i++) {
demo.printA();
}
}, "A").start();
new Thread(() -> {
for (int i = 0; i < 10; i++) {
demo.printB();
}
}, "B").start();
}
}
class LockDemo{
private ReentrantLock mylock = new ReentrantLock();
private Condition condition = mylock.newCondition();
private volatile boolean flag = false;
public void printA() {
try {
mylock.lock();
while (flag) {
condition.await();
}
System.out.println("A");
flag = true;
condition.signalAll();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
mylock.unlock();
}
}
public void printB() {
try {
mylock.lock();
while (!flag) {
condition.await();
}
System.out.println("B");
flag = false;
condition.signalAll();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
mylock.unlock();
}
}
public static void main(String[] args) {
LockDemo demo = new LockDemo();
new Thread(() -> {
for (int i = 0; i < 10; i++) {
demo.printA();
}
}, "A").start();
new Thread(() -> {
for (int i = 0; i < 10; i++) {
demo.printB();
}
}, "B").start();
}
}

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
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class ABC_LockCondition {
private static Lock lock = new ReentrantLock();
private static Condition A = lock.newCondition();
private static Condition B = lock.newCondition();
private static Condition C = lock.newCondition();
private static int count = 0;
static class ThreadA extends Thread {
@Override
public void run() {
try {
lock.lock();
for (int i = 0; i < 10; i++) {
while (count % 3 != 0)
A.await();
// 释放lock锁，ThreadC 会唤醒该线程继续执行
System.out.println("A");
count++;
B.signal();
}
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
}
static class ThreadB extends Thread {
@Override
public void run() {
try {
lock.lock();
for (int i = 0; i < 10; i++) {
while (count % 3 != 1)
B.await();
System.out.println("B");
count++;
C.signal();
}
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
}
static class ThreadC extends Thread {
@Override
public void run() {
try {
lock.lock();
for (int i = 0; i < 10; i++) {
while (count % 3 != 2) {
C.await();
}
System.out.println("C");
count++;
A.signal();
}
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
}
public static void main(String[] args) {
new ThreadA().start();
new ThreadB().start();
new ThreadC().start();
}
}