Java利用多線程做的一些習題（一）

題目

1、用多線程程序設計方式模擬鐵路售票，一共100張，通過四個窗口賣完。分別用實現多線程程序設計的兩種方式完成。

效果

1.多線程方式效果

2.線程池方式效果

代碼

1.多線程方式

package P1;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

import static java.lang.Thread.currentThread;
import static java.lang.Thread.sleep;

public class thread1 {


    public static void main(String[] args){

        Runnable window1=new Sold(100);
        Runnable window2=new Sold(100);
        Runnable window3=new Sold(100);
        Runnable window4=new Sold(100);

        Thread thread1=new Thread(window1);
        Thread thread2=new Thread(window2);
        Thread thread3=new Thread(window3);
        Thread thread4=new Thread(window4);

        thread1.start();
        thread2.start();
        thread3.start();
        thread4.start();

    }
}
class Sold implements Runnable{
    private static Lock lock = new ReentrantLock();
    private static Condition newSold=lock.newCondition();

    private static  int total;//火車票總數
    public Sold(int total) {
        this.total = total;
    }

    @Override
    public void run() {

        try {
            rest();
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    private   void rest() {
        lock.lock();
            try {
                while(total!=0){
                     Thread.sleep(5);
                    total-=1;
                    System.out.println("還剩"+total+"張票");
               }

            } catch (InterruptedException e) {
                e.printStackTrace();
            }finally {
                lock.unlock();

            }
        }

    }

2.線程池方式效果

package P1;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

import static java.lang.Thread.currentThread;
import static java.lang.Thread.sleep;

public class thread1 {


    public static void main(String[] args){
        //創建三個任務
        ExecutorService executor= Executors.newFixedThreadPool(4);


        executor.execute(new Sold(100));
        executor.execute(new Sold(100));
        executor.execute(new Sold(100));
        executor.execute(new Sold(100));

        executor.shutdown();

    }
}
class Sold implements Runnable{
    private static Lock lock = new ReentrantLock();
    private static Condition newSold=lock.newCondition();

    private static  int total;//火車票總數
    public Sold(int total) {
        this.total = total;
    }

    @Override
    public void run() {

        try {
            rest();
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    private synchronized void rest() {
        lock.lock();
            try {
                while(total!=0){
                     Thread.sleep(5);
                    total-=1;
                    System.out.println("還剩"+total+"張票");
               }

            } catch (InterruptedException e) {
                e.printStackTrace();
            }finally {
                lock.unlock();

            }
        }

    }

思路

因爲多線程的並行是交替運行的，所以會導致結果出現的順序不一致，所以使用加鎖的方式迫使線程一定要等到當前線程結束後才能運行。