常见代码问题
两个线程交替打印数字
使用Synchronized
注意wait（）、notify（）的使用
public class Comunication implements Runnable {
private int num = 1;
@Override
public void run() {
while (true) {
synchronized (this) {
this.notify();
if (num <= 100) {
System.out.println(Thread.currentThread().getName() + "num:" + num);
num++;
} else {
break;
}
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
使用ReetLock、condition
condition.signal()、以及condition.await()
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
/**
* @author SHshuo
* @data 2022/2/24--18:23
*/
public class Number implements Runnable{
private int num = 1;
ReentrantLock lock = new ReentrantLock();
Condition condition = lock.newCondition();
@Override
public void run() {
while(true){
lock.lock();
try{
condition.signal();
if(num <= 100){
System.out.println(Thread.currentThread().getName() + "num:" + num);
num++;
}else {
break;
}
condition.await();
}catch (InterruptedException e){
e.printStackTrace();
}finally {
lock.unlock();
}
}
}
}
共有部分
/**
* @author SHshuo
* @data 2022/2/24--18:11
*/
public class Test {
public static void main(String[] args) {
Number c = new Number();
// Comunication c = new Comunication();
Thread t1 = new Thread(c, "线程A");
Thread t2 = new Thread(c, "线程B");
t1.start();
t2.start();
}
}
创建10个线程、每个线程对一个共享变量进行加1、都加1w次
- 同花顺二面编程题
/**
* @author SHshuo
* @data 2022/9/26--16:34
*
* 创建10个线程、每个线程对一个共享变量进行加1、都加1w次
*/
public class hshuo {
private static int nums = 1;
private static Object lock = "lock";
public static void main(String[] args) {
for(int i = 0; i < 10; i++) {
new Thread(() -> {
synchronized (lock) {
for(int j = 0; j < 10000; j++) {
System.out.println(Thread.currentThread().getName() + "nums:" + nums);
nums++;
}
}
}).start();
}
}
}
生产者和消费者模型
定义一个字符串进行加锁、等待、唤醒等操作；
package com.hshuo;
/**
* @author SHshuo
* @data 2022/4/3--17:00
*/
public class WaitTest {
private static int count = 0;
private static final int buffCount = 10;
private static String lock = "lock";
class Producer implements Runnable {
@Override
public void run() {
while(true) {
try {
// 每个1秒生产一个
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
synchronized (lock) {
while (count == buffCount) {
try {
lock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
count++;
System.out.println(Thread.currentThread().getName() + "-生产者生产，数量为:" + count);
lock.notifyAll();
}
}
}
}
class Consumer implements Runnable {
@Override
public void run() {
while(true) {
try {
// 消费者3秒消费一个
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
synchronized (lock) {
while (count == 0) {
try {
lock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
count--;
System.out.println(Thread.currentThread().getName() + "-消费者消费，数量为：" + count);
lock.notifyAll();
}
}
}
}
public static void main(String[] args) {
WaitTest waitTest = new WaitTest();
// 10个消费者
for (int i = 0; i < 10; i++) {
new Thread(waitTest.new Consumer()).start();
}
new Thread(waitTest.new Producer()).start();
}
}
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