多线程同步
实现两个并行执行的线程的数据同步
（使用Java同步机制）
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| public class EmuExe {
public static void execute() {
try {
Thread.sleep((int) Math.random() * 1000);
} catch (Exception e) {
System.out.println("Exception!");
}
}
}
public class ThreadSync {
public static void main(String[] args) {
Object lock = new Object();
Flag flag = new Flag(true);
ThreadA thread1 = new ThreadA(lock, flag);
ThreadB thread2 = new ThreadB(lock, flag);
thread1.start();
thread2.start();
}
}
class Flag {
public boolean flag;
public Flag (boolean flag) {
this.flag = flag;
}
}
class ThreadA extends Thread {
public static volatile int A = 0;
private final Object lock;
private Flag flag;
public ThreadA(Object lock, Flag flag) {
this.lock = lock;
this.flag = flag;
}
@Override
public void run() {
for(int i = 0; i < 100; i++) {
if(ThreadA.A + ThreadB.B != 100) {
System.out.println("Error!");
}
System.out.println("the value of A is " + A);
synchronized (lock) {
flag.flag = !flag.flag;
if (flag.flag) {
lock.notify();
} else {
try {
lock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
incA();
if (i != 99) {
synchronized (lock) {
flag.flag = !flag.flag;
if (flag.flag) {
System.out.println("waiting A");
lock.notify();
} else {
try {
lock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
}
private void incA() {
A++;
EmuExe.execute();
}
}
class ThreadB extends Thread {
public static volatile int B = 100;
private final Object lock;
private Flag flag;
public ThreadB(Object lock, Flag flag) {
this.lock = lock;
this.flag = flag;
}
@Override
public void run() {
for(int i = 0; i < 100; i++) {
if(ThreadA.A + ThreadB.B != 100) {
System.out.println("Error");
}
System.out.println("the value of B is " + B);
synchronized (lock) {
flag.flag = !flag.flag;
if (flag.flag) {
lock.notify();
} else {
try {
lock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
decB();
if (i != 99) {
synchronized (lock) {
flag.flag = !flag.flag;
if (flag.flag) {
System.out.println("waiting B");
lock.notify();
} else {
try {
lock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
}
private void decB() {
B--;
EmuExe.execute();
}
}
|