1. 利用volatile状态标志实现（自己写的，哈哈）
package duoxiancheng.print;
public class PrintBai {
/*
1. 任务：两个线程交替的打印从1到100里面的奇数和偶数
2. 但是你如果查看打印结果会发现，其实当第一个线程运行的时候
另一个线程也没有闲着，也会在else里面打印，只是没有进入到它的if里面
3. 这样的方式可以满足交替打印的目的，但是效率不是很高，不推荐，我们再去尝试一下其它的方式
4. volatile 是必须要加的*/public static int i = 1;
public static volatile boolean flag = false;
public static void test() {
new Thread(() -> {
while (i <= 100) {
if (flag == false) {
System.out.println(Thread.currentThread().getName() + i);
i++;
flag = true;
}else {
//System.out.println("奇"+i);
}
}
}, "奇数线程：").start();
new Thread(() -> {
while (i <= 100) {
if (flag == true) {
System.out.println(Thread.currentThread().getName() + i);
i++;
flag = false;
}else {
//System.out.println("偶"+i);
}
}
}, "偶数线程：").start();
}public static void main(String[] args) {
test();
}
}2. 利用synchronized和线程通信
public class PrintOneToHundred2 {public static void main(String[] args) throws Exception {AtomicInteger ct = new AtomicInteger(0);
Thread a = new Thread(() -> {
try {
while (ct.get() < 100) {
synchronized (ct) {
System.out.println(Thread.currentThread().getName() + " :" + ct.incrementAndGet());
ct.notify();
ct.wait();
}
}
} catch (InterruptedException e) {} finally {}}, "odd");
Thread b = new Thread(() -> {
try {
while (ct.get() < 100) {
synchronized (ct) {
System.out.println(Thread.currentThread().getName() + " :" + ct.incrementAndGet());
ct.notify();
ct.wait();
}
}
} catch (InterruptedException e) {} finally {}
}, "even");
a.start();
a.join(10);
b.start();
}}3. 利用线程锁
package duoxiancheng.print;
import java.util.concurrent.locks.ReentrantLock;
/**
* Created by szh on 2019/1/17.
*
* @author szh
*/
public class PrintOneToHundred {static volatile int ct = 1;
public static void main(String[] args) {ReentrantLock reentrantLock = new ReentrantLock();
Thread a = new Thread(() -> {
try {
while (!(ct >= 100)) {
while ((ct%2==0)){
reentrantLock.lock();
ct++;
System.out.println(Thread.currentThread().getName() + " " + ct);
reentrantLock.unlock();
}
}
} finally {}
}, "odd");
Thread b = new Thread(() -> {
try {
while (!(ct >= 100)) {
while ((ct%2==1)){
reentrantLock.lock();
ct++;
System.out.println(Thread.currentThread().getName() + " " + ct);
reentrantLock.unlock();
}
}
} finally {}
}, "even");
a.start();
b.start();
}}利用公平锁
package duoxiancheng.reentrantLock;
import java.util.concurrent.locks.ReentrantLock;
public class FairLock implements Runnable{
// 必须是true，如果是false，那就是不公平的，不公平就不会出现交替打印的结果了
//因为你不知道一个线程什么时候会释放它的锁
public static ReentrantLock fairLock = new ReentrantLock(true);
static volatile int ct = 0;
public void run() {
while (ct<100) {
try {
fairLock.lock();
System.out.println(Thread.currentThread().getName()+"，获得锁!"+ct);
ct++;
}finally {
fairLock.unlock();
System.out.println(Thread.currentThread().getName()+"，释放锁!"+ct);
}
}
}
public static void main(String[] args) {
FairLock fairLock = new FairLock();
Thread t1 = new Thread(fairLock, "线程1");
Thread t2 = new Thread(fairLock, "线程2===");
t1.start();
t2.start();
}
}
