将不安全的map集合转成安全集合
HashMap HashMap = new HashMap<>();
Collections.synchronizedMap(HashMap);
concurrentHasMap 开发推荐使用这种map———线程安全且效率高
CountDownLatch
public class Test002 {
public static void main(String[] args) throws InterruptedException {
CountDownLatch countDownLatch = new CountDownLatch(1);
new Thread(new Runnable() {
public void run() {
System.out.println("我是子线程开始执行任务......");
try {
//子线程正在处理事情
Thread.sleep(10);
} catch (Exception e) {
// TODO: handle exception
}
countDownLatch.countDown();//每次减1
System.out.println("我是子线程开始执行任务......");
}
}).start();;
new Thread(new Runnable() {
public void run() {
System.out.println("我是子线程开始执行任务......");
try {
//子线程正在处理事情
Thread.sleep(10);
} catch (Exception e) {
// TODO: handle exception
}
countDownLatch.countDown();//每次减1
System.out.println("我是子线程开始执行任务......");
}
}).start();
countDownLatch.await();//如果不为0的时候，一直等待
System.out.println("主线程开始执行任务");
for (int i = 0; i < 10; i++) {
System.out.println("main i:"+i);
}
}
}
CyclicBarrier
class Writer extends Thread {
CyclicBarrier cyclicBarrier;
public Writer(CyclicBarrier cyclicBarrier){
this.cyclicBarrier=cyclicBarrier;
}
@Override
public void run() {
System.out.println(Thread.currentThread().getName() + "开始写入数据...");
try {
// 模拟耗时时间
Thread.sleep(30);
// 执行并行执行成功
System.out.println(Thread.currentThread().getName() + "写入数据成功...");
cyclicBarrier.await();
System.out.println(Thread.currentThread().getName() + "所有数据执行完毕...");
} catch (Exception e) {
// TODO: handle exception
}
}
}
public class Test003 {
public static void main(String[] args) {
CyclicBarrier cyclicBarrier= new CyclicBarrier(5);
for (int i = 0; i < 5; i++) {
new Writer(cyclicBarrier).start();
}
}
}
class Parent extends Thread {
Semaphore wc;
String name;
public Parent(Semaphore wc, String name) {
this.wc = wc;
this.name = name;
}
@Override
public void run() {
// 获取到资源，减去1
int availablePermits = wc.availablePermits();
if (availablePermits > 0) {
System.out.println(name + "天主我也，我有茅坑啦!!");
} else {
System.out.println(name + "怎么没有茅坑了.....");
}
try {
wc.acquire();
System.out.println(name+"终于能上厕所了，爽!!!");
Thread.sleep(new Random().nextInt(1000)); // 模拟上厕所时间。
System.out.println(name+"厕所终于上完啦!");
} catch (InterruptedException e) {
}finally {
//释放茅坑
wc.release();
}
}
}
public class Test004 {
public static void main(String[] args) throws InterruptedException {
Semaphore semaphore = new Semaphore(3);
for (int i = 1; i <=10; i++) {
new Parent(semaphore,"第"+i+"个"+",").start();
}
}
}
