readerlovewriter.java

读者写者进程JAVA编写

import java.io.*;
import java.util.*;


public class ReaderLoveWriter 
{
	public static void main(String args[])throws Exception
	{
	     VisitData visit=new VisitData();
	
	
		Scanner scan=new Scanner(new File("threads.txt"));
		//文件开头要写清多少个线程
		int m=scan.nextInt();//第一个读到的是线程的总数目
		int a[][]=new int[m][3];//记录每个线程的信息。a[m][0]是读/写，a[m][1]是等待时间，a[m][2]是读/写时间
		int h=0;
		int writeThread=0,readThread=0;//读写数分别多少
		int readerNum=0,writerNum=0;
		while(scan.hasNext())
		{
		  String str=scan.next();
		  //System.out.print(str);
		  if(str.equals("W")) //是写线程
		  {
		  	writeThread++;
		  	a[h][0]=0;     //0 表示是 写 
		  	a[h][1]=scan.nextInt();//开始时间
		  	a[h][2]=scan.nextInt();//持续时间
		  	h++;
		  }
		   else               //读线程
		   {
		   	readThread++;
		   	a[h][0]=0;
		  	a[h][1]=scan.nextInt();
		  	a[h][2]=scan.nextInt();
		  	h++;
		   }
		 }
		 //System.out.println(h+""+readThread+""+writeThread);
		 int i=0,n=0;
		 Writer threadw[]=new Writer[writeThread];//建立线程
		 Reader threadr[]=new Reader[readThread];
		 for(int k=0;k<m;k++)
		 {
		 	
		 	if(a[k][0]==0&&i<writeThread)
		 	{ 
		 	  
		 	  threadw[i]=new Writer(i+1,a[k][1],a[k][2],visit);//线程号，等待时间，读/写时间，主要方法。
		 	  i++;	
		 	}
		 	else
		 	{
		 	   threadr[n]=new Reader(n+1,a[k][1],a[k][2],visit);
		 	   n++;
		 	}
		 }
		
		 
		 for(int t=0;t<i;t++)
		 threadw[t].start();//写进程开始
		 for(int p=0;p<n;p++)
		 threadr[p].start();//读进程开始
		
		
	}
}


class Reader extends Thread
{
	public int waitTime,doingTime,readerNum;//等待时间，读时间，读者数
	public VisitData visit;
	public Reader(int readerNum,int waitTime,int doingTime,VisitData visit )
	{
		super();
		this.waitTime=waitTime;//等待时间
		this.doingTime=doingTime;//读时间
		this.readerNum=readerNum;//读者号
		this.visit=visit;
		
	}
	
	 public void run()
	{
		while(true){
	  try
		{
			
			Thread.sleep(waitTime*1000);
			
		}
		catch(Exception e){e.printStackTrace();}
		
	  	System.out.println("-----读者"+readerNum+"----请求读^0^\n");
	  	
	      visit.startRead(readerNum);//开始读
	      System.out.println("-----读者"+readerNum+"----正在读。。。。^0^\n");
	      visit.doing(doingTime);//读书中。。
	      visit.endRead(readerNum); //读完
	 }
	  	
	}
}
class Writer extends Thread
{
	public int waitTime,doingTime,writerNum;
	public VisitData visit;
	public Writer(int writerNum,int waitTime,int doingTime,VisitData visit )
	{
		super();
		this.waitTime=waitTime;//等待时间
		this.doingTime=doingTime;//写时间
		this.writerNum=writerNum;//写者号
		this.visit=visit;
	}
	
	 public void run()
	{
		while(true){
	  try
		{
			
			Thread.sleep((waitTime+1)*1000);//一直等到这个线程开始的时间
			
		}
		catch(Exception e){e.printStackTrace();}
		
	  	System.out.println("-----写者"+writerNum+"----请求写^0^\n");
	  	visit.startWrite(writerNum);//开始写
	      System.out.println("-----写者"+writerNum+"----正在写。。。。^0^\n");	
	  	visit.doing(doingTime);//正在写
	  	visit.endWrite(writerNum);//结束写
	  	
	  }
	  	
	}
}
class VisitData //访问数据
{
	 private int readerCount;
	 private int writerCount;
	 private boolean beReading;//是否有人在读
	 private boolean beWriting;//是否有人在写
	 public VisitData() //初始化
	 {
		 super();
		 readerCount=0;
		 writerCount=0;
		 beReading=false;
		 beWriting=false;
  
       }
    
	 public  void doing(int sleepTime )//用来表示正在读或写
	 {
	  
		  try{
		         Thread.sleep((sleepTime+1)*1000);
		     }catch(Exception e){e.printStackTrace();}
		     
	 }
 
	 public synchronized void startRead(int reader)
	 {
		  while(writerCount>0)
		  {
			   try{
				    System.out.println("-----读者"+reader+"----等待中。。。。^0^\n");
				    wait();
		            }catch(Exception e){e.printStackTrace();}
		  }
		  readerCount++;
		  if(readerCount>=1)
		  {
		         beReading=true;//表示有人在读
		  }
	  
	  
	 }
	 
	 public synchronized void endRead(int reader)
	 {
		  --readerCount;
		  if(readerCount==0)
		  {
		        beReading=false;//表示没人在读
		  }
		  notifyAll();
		  System.out.println("-----读者"+reader+"----读结束^0^\n");
	  
	 }
 
	 public synchronized void startWrite(int writer)
	 {
		  ++writerCount;
		  while(beReading==true||beWriting==true)//当有读者或是写者在读或是写的话
		  {
			   try
			   {
			    System.out.println("-----写者"+writer+"----等待中。。。。^0^\n");
			    wait();
			   }catch(Exception e){System.out.println(e.toString());}
		    
	        }
		  beWriting =true;
       }
	 public synchronized void endWrite(int writer)
	 {
		  --writerCount;
		  beWriting=false;
		  System.out.println("-----写者"+writer+"----写结束^0^\n");
	        notifyAll();//通知其他人
	 }
	 
       
}