ReentrantLock锁并发环境线程安全读写ArrayList，Kotlin

喜欢ヅ旅行 2023-10-14 13:06 16阅读 0赞

### ReentrantLock锁并发环境线程安全读写ArrayList，Kotlin ###

###  ###

import kotlinx.coroutines.*
    import java.util.concurrent.locks.ReentrantLock
    import kotlin.collections.ArrayList
    
    /**
     * 假设这样一种场景：在多线程的并发环境中，不同的线程/协程对于一个线程不安全的列表读写，确保数据写入后，被读取出来是正确无误的。
     *
     */
    fun main() {
        val lock = ReentrantLock()
        var list = ArrayList<String>()
    
        runBlocking {
            CoroutineScope(Dispatchers.IO).launch {
                while (true) {
                    delay((Math.random() * 10 + 100).toLong())
    
                    lock.lock()
                    println("R--->${list[list.size - 1]}") //这里很容易发生数组越界问题。
                    lock.unlock()
                }
            }
    
            while (true) {
                val l = ArrayList<String>()
                for (i in 0..<(Math.random() * 10 + 10).toInt()) {
                    l.add("$i")
                }
    
                lock.lock()
                list.clear()
                list.addAll(l)
                println("W-${list.size}")
                lock.unlock()
    
                delay((Math.random() * 10).toLong())
            }
        }
    }

> W-14  
> W-10  
> W-11  
> W-10  
> W-15  
> W-14  
> W-14  
> W-10  
> W-14  
> W-14  
> R--->13  
> W-11  
> W-15  
> W-14  
> W-10  
> W-12  
> W-11  
> W-12  
> R--->11  
> W-16  
> W-19  
> W-11  
> W-16  
> W-14  
> W-16  
> W-10  
> R--->9  
> W-12  
> W-17  
> W-11  
> W-16  
> W-10  
> W-19  
> W-16  
> W-16  
> W-14  
> W-12  
> R--->11  
> W-12  
> W-13  
> W-16  
> W-14  
> W-17  
> W-15  
> W-13  
> R--->12

[ReentrantLock替换synchronized解决多线程并发死锁，Java\_reentrantlock解决死锁问题的代码\_zhangphil的博客-CSDN博客Java并发多线程环境中，造成死锁的最简单的场景是：多线程中的一个线程T\_A持有锁L1并且申请试图获得锁L2，而多线程中另外一个线程T\_B持有锁L2并且试图申请获得锁L1。线程的锁申请操作是阻塞的，于是造成线程T\_A和线程T\_B无法正确获得想要的锁，两个线程被阻塞进入死锁状态。Java线程同步锁ReentrantLock和Condition中断等待程序前提条件满足\_zhangphil的博客-CSDN博客。\_reentrantlock解决死锁问题的代码![favicon32.ico][]https://blog.csdn.net/zhangphil/article/details/127548507][ReentrantLock_synchronized_Java_reentrantlock_zhangphil_-CSDN_Java_T_A_L1_L2_T_B_L2_L1_T_A_T_B_Java_ReentrantLock_Condition_zhangphil_-CSDN_reentrantlock_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_127548507]

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