JAVA实验六：线程

实验目的

1. 掌握线程的概念。
2. 掌握线程的创建方法。
3. 掌握线程的常用方法。
4. 掌握线程同步的方法
5. 掌握线程联合的方法。

实验内容

将实验6文件夹中所附的源程序“RWthread.java”改为用线程联合实现。

实验代码

原RWthread.java代码

import java.util.*;
class RWthread
{
    public static void main(String args[])
    {
        String readName="读线程",writeName="写线程";
        ReadWrite rw=new ReadWrite(readName,writeName);
        Thread read,write;
        read=new Thread(rw);
        write=new Thread(rw);
        read.setName(readName);
        write.setName(writeName);
        read.start();
        write.start();
    }
}
class ReadWrite implements Runnable
{
    String ID=null;
    String name=null;
    String readName,writeName;
    boolean flag=false;
    public ReadWrite(String s1,String s)
    {
        readName=s1;
        writeName=s;
    }
    public void run()
    {
        readOrWrite(); 
    }
    public synchronized void readOrWrite() //同步方法
    {
        if(Thread.currentThread().getName().equals(readName)) 
        {
            Scanner reader=new Scanner(System.in);
            while(true)
            {
                if(flag)
                {
                    try{
                        wait();
                    }catch(InterruptedException e){}
                }
                System.out.println("请输入学号：");
                ID=reader.nextLine();
                if(ID.equals("finish"))
                {
                    System.out.println("\n读线程和写线程工作结束！");
                    flag=true;
                    notify();
                    reader.close();
                    return;
                }
                System.out.println("请输入姓名：");
                name=reader.nextLine();
                flag=true;
                notify();
            }
        }
        else if(Thread.currentThread().getName().equals(writeName))
        {
            while(true)
            {
                if(!flag)
                {
                    try{
                        wait();
                    }catch(InterruptedException e){}
                }
                if(ID.equals("finish"))
                    return;
                System.out.println("\n输出学号："+ID+"，输出姓名："+name);
                System.out.println();
                flag=false;
                notify();
            }
        }
    }  
}

改成线程联合实现后

import java.util.*;
class RWthread
{
    public static void main(String args[])
    {
        ReadWrite rw=new ReadWrite();
        rw.write.start();
    }
}
class ReadWrite implements Runnable
{
    String ID=null;
    String name=null;
    boolean flag=false;
    String readName="读线程",writeName="写线程";
    Thread read,write;
    ReadWrite()
    {
        write=new Thread(this);
        write.setName(writeName);
    }
    public void run()
    {
        if(Thread.currentThread().getName().equals(readName)) 
        {

                Scanner reader=new Scanner(System.in);
                System.out.println("请输入学号：");
                ID=reader.nextLine();
                if(ID.equals("finish"))
                {
                    System.out.println("\n读线程和写线程工作结束！");

                    reader.close();
                    return;
                }
                System.out.println("请输入姓名：");
                name=reader.nextLine(); 
        }
        else if(Thread.currentThread().getName().equals(writeName))
        {
            while(true)
            {
                if(read!=null)
                {
                    read.stop();
                }
                read=new Thread(this);
                read.setName(readName);
                read.start();
                    try{
                        read.join();    
                    }catch(InterruptedException e){}
                if(ID.equals("finish"))
                    return;
                System.out.println("\n输出学号："+ID+"，输出姓名："+name);
                System.out.println();
            }
        }
    }
}