java 是否可以同时读取和写入文件？
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Is it possible to read and write in file at the same time?
提问by mohamida
Here's the scenario:
这是场景：
- ThreadA is going to read from some socket, and write data to "MyFile.txt"
- ThreadB is going to read "MyFile", and when it reaches the end, it will loops until new data are available in MyFile (because i don't want to re-open "MyFile.txt", and lose the time so i reach the position from where i was..).
- ThreadA 将从某个套接字读取，并将数据写入“MyFile.txt”
- ThreadB 将读取“MyFile”，当它到达末尾时，它将循环直到 MyFile 中有新数据可用（因为我不想重新打开“MyFile.txt”，并且浪费时间所以我到达我所在的位置......）。
Is it possible to do such a thing ?
有可能做这样的事情吗？
If not, is there another way to do such a thing ?
如果没有，还有另一种方法可以做这样的事情吗？
回答by Cheok Yan Cheng
The problem you mention is a famous Producer Consumer Problem
你提到的问题是著名的生产者消费者问题
Common solution to this is to use BlockingQueue
对此的常见解决方案是使用BlockingQueue
An example of real world usage is in AjaxYahooSearchEngineMonitor
AjaxYahooSearchEngineMonitor是真实世界使用的一个例子
What Thread A does is, it will submit a string to queue, and then return immediately.
线程A所做的是，它会向队列提交一个字符串，然后立即返回。
What Thread B does is, it will pick up the item from queue one by one, and process them. When there is no item in the queue, Thread B will just wait there. See line 83 of the source code.
线程B所做的就是，它会从队列中一个一个地取出项目，并对其进行处理。当队列中没有项目时，线程 B 将在那里等待。请参阅源代码的第 83 行。
