Future模式简单实现

1. 概述，Future模式是多线程开发中比较常见模式，核心思想是异步调用，思路是执行函数时，马上得到返回结果，但是并不急于处理，而去执行其它业务逻辑，最后再使用比较慢的数据，就不存在无谓的等待，充分利用的所有的时间片段。提高响应速度
2. FutureData

public class FutureData implements Data {    protected RealData realdata=null;  //FutureData是真实数据包装    protected boolean isReady=false;    public synchronized void setRealdata(RealData realdata) {        if (isReady) {            return;        }        this.realdata=realdata;        isReady=true;        notifyAll();  //数据完成，通知getResult    }    @Override    public String getResult() {        // TODO Auto-generated method stub        while(!isReady)        {            try {                wait();            } catch (InterruptedException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        return realdata.result;    }}

3.RealData

public class RealData implements Data {   protected final String result;    public RealData(String para) {        // TODO Auto-generated constructor stub        StringBuffer sb=new StringBuffer();        for(int i=0;i<5;i++)        {            sb.append(para);            try {                Thread.sleep(1000);  //模拟很慢的加载速度            } catch (InterruptedException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        System.out.println("数据完成");        System.out.println(System.currentTimeMillis()/1000);        result=sb.toString();    }    @Override    public String getResult() {        // TODO Auto-generated method stub        return result;    }}

4.Data

public interface Data {   public String getResult();}

5.client

public class Client {  public Data request (final String querystr)  {      final FutureData futureData=new FutureData();      new Thread(){         public void run() {             RealData realData=new  RealData(querystr);             futureData.setRealdata(realData);         };      }.start();      return futureData;  }}

6.Main

public class Main {    public static void main(String[] args) {        // TODO Auto-generated method stub      Client client=new Client();      Data data=client.request("name");      System.out.println("请求完毕");      try {        Thread.sleep(7000);    } catch (InterruptedException e) {        // TODO Auto-generated catch block        e.printStackTrace();    }      System.out.println(System.currentTimeMillis()/1000);      System.out.println("数据"+data.getResult());    }}

7.参考自java高并发程序设计