这篇文章主要介绍了Java多线程的临界资源问题解决方案,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

临界资源问题的原因：某一个线程在对临界资源进行访问时，还没来得及完全修改临界资源的值，临界资源就被其他线程拿去访问，导致多个线程访问同一资源。直观表现为打印结果顺序混乱。

解决方法：加锁

静态方法中用类锁，非静态方法中用对象锁。

1.同步代码段：synchronized（）{...}

2.同步方法：使用关键字synchronized修饰的方法

3.使用显式同步锁ReentrantLock

锁池描述的即为锁外等待的状态

方法一：同步代码段：synchronized（）{...}

public class SourceConflict { public static void main(String[] args) { //实例化4个售票员，用4个线程模拟4个售票员 Runnable r = () -> { while (TicketCenter.restCount > 0) { synchronized(" ") { if (TicketCenter.restCount <= 0) { return; } System.out.println(Thread.currentThread().getName() + "卖出一张票，剩余" + --TicketCenter.restCount + "张票"); } } }; //用4个线程模拟4个售票员 Thread thread1 = new Thread(r, "thread-1"); Thread thread2 = new Thread(r, "thread-2"); Thread thread3 = new Thread(r, "thread-3"); Thread thread4 = new Thread(r, "thread-4"); //开启线程 thread1.start(); thread2.start(); thread3.start(); thread4.start(); } }//实现四名售票员共同售票，资源共享，非独立//Lambda表达式或匿名内部类内部捕获的局部变量必须显式的声明为 final 或实际效果的的 final 类型，而捕获实例或静态变量是没有限制的class TicketCenter{ public static int restCount = 100; }

方法二：同步方法，即使用关键字synchronized修饰的方法

public class SourceConflict2 { public static void main(String[] args) { //实例化4个售票员，用4个线程模拟4个售票员 Runnable r = () -> { while (TicketCenter.restCount > 0) { sellTicket(); } }; //用4个线程模拟4个售票员 Thread thread1 = new Thread(r, "thread-1"); Thread thread2 = new Thread(r, "thread-2"); Thread thread3 = new Thread(r, "thread-3"); Thread thread4 = new Thread(r, "thread-4"); //开启线程 thread1.start(); thread2.start(); thread3.start(); thread4.start(); } private synchronized static void sellTicket() { if (TicketCenter.restCount <= 0) { return; } System.out.println(Thread.currentThread().getName() + "卖出一张票，剩余" + --TicketCenter.restCount + "张票"); }}class TicketCenter{ public static int restCount = 100; }

方法三：使用显式同步锁ReentrantLock

import java.util.concurrent.locks.ReentrantLock;public class SourceConflict3 { public static void main(String[] args) { //实例化4个售票员，用4个线程模拟4个售票员 //显式锁 ReentrantLock lock = new ReentrantLock(); Runnable r = () -> { while (TicketCenter.restCount > 0) { lock.lock(); if (TicketCenter.restCount <= 0) { return; } System.out.println(Thread.currentThread().getName() + "卖出一张票，剩余" + --TicketCenter.restCount + "张票"); lock.unlock(); } }; //用4个线程模拟4个售票员 Thread thread1 = new Thread(r, "thread-1"); Thread thread2 = new Thread(r, "thread-2"); Thread thread3 = new Thread(r, "thread-3"); Thread thread4 = new Thread(r, "thread-4"); //开启线程 thread1.start(); thread2.start(); thread3.start(); thread4.start(); } }class TicketCenter{ public static int restCount = 100; }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。