基于java对操作系统进程管理问题读者与写者编写代码测试

好的，以下是一个基于Java的读者写者问题的代码示例，使用了线程和锁来实现进程管理：

import java.util.concurrent.locks.*;

class ReadWriteLock {
    private int readers = 0;
    private int writers = 0;
    private int writeRequests = 0;

    private Lock lock = new ReentrantLock();
    private Condition readersCondition = lock.newCondition();
    private Condition writersCondition = lock.newCondition();

    public void lockRead() throws InterruptedException {
        lock.lock();
        try {
            while (writers > 0 || writeRequests > 0) {
                readersCondition.await();
            }
            readers++;
        } finally {
            lock.unlock();
        }
    }

    public void unlockRead() throws InterruptedException {
        lock.lock();
        try {
            readers--;
            if (readers == 0) {
                writersCondition.signal();
            }
        } finally {
            lock.unlock();
        }
    }

    public void lockWrite() throws InterruptedException {
        lock.lock();
        try {
            writeRequests++;
            while (readers > 0 || writers > 0) {
                writersCondition.await();
            }
            writeRequests--;
            writers++;
        } finally {
            lock.unlock();
        }
    }

    public void unlockWrite() throws InterruptedException {
        lock.lock();
        try {
            writers--;
            if (writers == 0) {
                readersCondition.signal();
            } else {
                writersCondition.signal();
            }
        } finally {
            lock.unlock();
        }
    }
}

class Reader extends Thread {
    private ReadWriteLock rwLock;
    private int id;

    public Reader(int id, ReadWriteLock rwLock) {
        this.id = id;
        this.rwLock = rwLock;
    }

    public void run() {
        try {
            while (true) {
                rwLock.lockRead();
                System.out.println("Reader " + id + " is reading");
                Thread.sleep((int) (Math.random() * 1000));
                rwLock.unlockRead();
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

class Writer extends Thread {
    private ReadWriteLock rwLock;
    private int id;

    public Writer(int id, ReadWriteLock rwLock) {
        this.id = id;
        this.rwLock = rwLock;
    }

    public void run() {
        try {
            while (true) {
                rwLock.lockWrite();
                System.out.println("Writer " + id + " is writing");
                Thread.sleep((int) (Math.random() * 1000));
                rwLock.unlockWrite();
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

public class ReaderWriterProblem {
    public static void main(String[] args) {
        ReadWriteLock rwLock = new ReadWriteLock();

        for (int i = 0; i < 5; i++) {
            new Reader(i + 1, rwLock).start();
        }

        for (int i = 0; i < 2; i++) {
            new Writer(i + 1, rwLock).start();
        }
    }
}

这个示例代码实现了一个简单的读者写者问题，其中有多个读者和多个写者，读者和写者共享一个资源。在这个示例中，读者和写者都是线程，它们使用锁来互斥地访问这个共享资源。读者可以同时访问资源，而写者必须排他地访问资源。因此，在这个示例中，读者和写者都使用了一个自定义的锁，这个锁包含了读者和写者的计数器以及一个写请求的计数器。读者和写者在获取锁和释放锁时，都需要遵循一定的规则，以保证它们之间的互斥性和协作性。