生產(chǎn)者與消費者模型

• 通過使用Object的wait(),notify()方法進行生產(chǎn)者與消費者模型中出現(xiàn)的數(shù)據(jù)同步與數(shù)據(jù)重復(fù)操作問題
• 示例

package design;
/**
   * 生產(chǎn)者與消費者模型
   */
public class ProvideAndConsumer {
    public static void main(String[] args) {
        Data data = new Data();
        new Thread(new Provider(data)).start();
        new Thread(new Consumer(data)).start();
    }
}
/**
   * 數(shù)據(jù)類
   */
class Data{
    private String title;
    private Double price;
    /**
     * flag=true:可生產(chǎn),但不可消費
     * flag=false:可消費但不可生產(chǎn)
     */
    private boolean flag=true;
    /**
     * 使用同步方法保證數(shù)據(jù)同步,使用開關(guān)flag,解決數(shù)據(jù)重復(fù)操作問題
     * @param title
     * @param price
     */
    public synchronized void set(String title,Double price) {
        if(this.flag==false){
            try {
                super.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        //延遲,以觀察
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        this.title=title;
        this.price=price;
        this.flag=false;
        super.notify();
    }
    /**
     * 使用同步方法保證數(shù)據(jù)同步,使用開關(guān)flag,解決數(shù)據(jù)重復(fù)操作問題
     */
    public synchronized void get() {
        if(this.flag==true){
            try {
                super.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        //延遲,以觀察
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(this);
        this.flag=true;
        super.notify();
    }
    @Override
    public String toString() {
        return "Data{" +
                "title='" + title + '\'' +
                ", price=" + price +
                '}';
    }
}
/**
   * 生產(chǎn)者
   */
class Provider implements Runnable{
    private Data data;
    public Provider (Data data){
        this.data=data;
    }
    @Override
    public void run() {
        for(int i =0;i<10;i++){
            if(i %2==0){
                this.data.set("Java",18.9);
            }else{
                this.data.set("Php",8.9);
            }
        }
    }
}
/**
   * 消費者
   */
class Consumer implements Runnable{
    private Data data;
    public Consumer (Data data){
        this.data=data;
    }
    @Override
    public void run() {
        for(int i =0;i<10;i++){
            this.data.get();
        }
    }
}

線程池

• 線程池核心接口：

• 普通執(zhí)行線程池定義：java.util.concurrent.ExecutorService
• 調(diào)度線程池：java.util.concurrent.ScheuledExecutorService

• 線程池創(chuàng)建類：java.util.concurrent.Executors

• 創(chuàng)建無大小限制的線程池：public static ExecutorService newCachedThreadPool()
• 創(chuàng)建指定現(xiàn)成大小的線程池：public static ExecutorService newFixedThreadPool(int nThreads)
• 創(chuàng)建單線程池：public static ExecutorService newSingleThreadExecutor()
• 創(chuàng)建定時調(diào)度池：public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize)