问题1
实现一个容器，提供两个方法，add，size，写两个线程，线程1添加10个元素到容器中，线程2实现监控元素的个数，当到5个时候，线程2给出提示并结束。
考点：锁的应用wait和notify 以及其他锁的应用
import java.util.ArrayList; import java.util.List; public class TaobaoTest { public static void main(String[] args) { Container container = new Container(); Object lock = new Object(); new Thread(() -> { synchronized (lock) { System.out.println("t2启动"); try { lock.wait(); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("判断是第五个打印"); lock.notify(); } return; },"t2").start(); new Thread(() -> { synchronized (lock) { System.out.println("t1启动"); try { for (int i = 0; i < 10; i++) { if (container.size() == 5) { lock.notify(); System.out.println("叫t1打印"); lock.wait(); } container.add("a"); } } catch (InterruptedException e) { e.printStackTrace(); } } },"t1").start(); } } /** * 容器 */ class Container { private volatile List<String> list = new ArrayList<>(); public void add(String a) { list.add(a); } public int size() { return list.size(); } }问题2 写一个固定容量的同步容器，拥有put和get方法，以及getcount方法，能够支持2个生产者以及10个消费者阻塞调用
使用ReentrantLock的Condition来实现生产着消费者
import java.util.ArrayList; import java.util.LinkedList; import java.util.List; import java.util.Queue; import java.util.concurrent.locks.Condition; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; public class TaobaoTest03 { public static void main(String[] args) { Box box = new Box(); List<Thread> threadList = new ArrayList<>(); //两个生产者 for (int i = 0; i < 2; i++) { threadList.add(new Thread(() -> { int j = 0; Thread t = Thread.currentThread(); String name = t.getName(); for (int k = 0; k < 50; k++) { try { box.put(j); System.out.println(name + "线程put数字" + j); } catch (InterruptedException e) { e.printStackTrace(); } } }, "put" + i)); } //十个消费者 for (int i = 0; i < 10; i++) { threadList.add(new Thread(() -> { System.out.println("get启动"); Thread t = Thread.currentThread(); String name = t.getName(); for (int j = 0; j < 10; j++) { try { System.out.println(name + "线程get到数字" + box.get()); } catch (InterruptedException e) { e.printStackTrace(); } } }, "get" + i)); } //启动所有 threadList.forEach((o) -> o.start()); } } class Box { private final Queue<Integer> bigBox = new LinkedList<>(); Lock lock = new ReentrantLock(); Condition producer = lock.newCondition(); Condition consumer = lock.newCondition(); private int count = 0; private final int MAX = 10; public Integer get() throws InterruptedException { lock.lock(); //如果数量不够了，直接进入等待队列 while (count == 0) { //判断count是否是0是0就停止消费 consumer.await(); System.out.println("生产满了停止了" ); } Integer get = bigBox.poll(); ++count; producer.signalAll(); lock.unlock(); return get; } public void put(Integer integer) throws InterruptedException { lock.lock(); while (count == MAX) { producer.await(); System.out.println("消费完了停止了" ); } --count; bigBox.offer(integer); consumer.signalAll(); lock.unlock(); } }
