1、案例分析：
你去商店买蛋糕，付完钱后蛋糕店老板会给你一张订单然后让你晚上来取，你拿到订单后接着干自己的事情了，老板让蛋糕师傅做蛋糕，等着晚上的时候你拿出订单取回蛋糕。
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2、程序设计
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package com.metarnet.FuturePattern;
/**
* 人的类，通过该类获取一个请求
* @author Administrator
*
*/
public class Host {
public Data getRequest(final int count, final char c) {
System.out.println("(request count = " + count + ", c = " + c + " begin )");
final FutureData future = new FutureData();
new Thread() {
@Override
public void run() {
RealData realData = new RealData(count, c);
future.setRealData(realData);
}
}.start();
System.out.println("(request count = " + count + ", c = " + c + " end )");
return future;
}
}
package com.metarnet.FuturePattern;
/**
* 数据接口，返回内容
* @author Administrator
*
*/
public interface Data {
public String getContent();
}
package com.metarnet.FuturePattern;
/**
* 相当于订单类，立即返回的信息，之后通过该类的方法去获取真正的内容
* @author Administrator
*
*/
public class FutureData implements Data {
private RealData realData;
private boolean ready = false;
public RealData getRealData() {
return realData;
}
public synchronized void setRealData(RealData realData) {
if(realData.isReady()) {
this.realData = realData;
ready = true;
this.notifyAll();
}
}
@Override
public String getContent() {
synchronized(this) {
while(!ready) {
try {
wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return realData.getContent();
}
}
}
package com.metarnet.FuturePattern;
/**
* 真的处理的类，在FutureData里面注册了，等内容处理完后通过FutureData调用getContent方法获取内容
* 启动新的线程去处理该类
* @author Administrator
*
*/
public class RealData implements Data {
private String content;
private boolean ready = false;
public RealData(int count, char c) {
doParse(count, c);
}
@Override
public String getContent() {
return content;
}
public void doParse(int count, char c) {
System.out.println("making (count = " + count + ", c = " + c + " ) begin..." );
char[] chars = new char[count];
for(int i=0; i<count; ++i) {
chars[i] = c;
}
try {
Thread.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("making (count = " + count + ", c = " + c + " ) end..." );
this.content = new String(chars);
ready = true;
}
public boolean isReady() {
return ready;
}
public void setReady(boolean ready) {
this.ready = ready;
}
}
package com.metarnet.FuturePattern;
public class TestMain {
public static void main(String[] args) {
Host host = new Host();
Data f1 = host.getRequest(10, 'A');
Data f2 = host.getRequest(30, 'B');
Data f3 = host.getRequest(20, 'C');
System.out.println("main begin...");
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(f1.getContent());
System.out.println(f2.getContent());
System.out.println(f3.getContent());
System.out.println("main end...");
}
}
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?3、在获取网页信息的程序：
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package com.metarnet.FuturePattern.URLContent;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
public class Main {
public static void main(String[] args) {
Retriver test = new Retriver();
try {
Content content1 = test.getContent("http://www.sina.com");
Content content2 = test.getContent("http://www.yahoo.cn");
Content content3 = test.getContent("http://www.hhstu.edu.cn");
Thread.sleep(5000);
saveToFile("yahoo.html", content1);
saveToFile("goole.html", content2);
saveToFile("hhstu.html", content3);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private static void saveToFile(String name, Content content1) {
File file = new File("E:" + File.separator + "html");
if(!file.exists()) {
file.mkdirs();
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
FileOutputStream output = null;
try {
output = new FileOutputStream(file + File.separator + name);
output.write(content1.getBytes());
output.close();
System.out.println(name + "生成成功！");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if(output != null) {
try {
output.close();
} catch (IOException e) {
e.printStackTrace();
}
output = null;
}
}
}
}
package com.metarnet.FuturePattern.URLContent;
public interface Content {
public byte[] getBytes();
}
package com.metarnet.FuturePattern.URLContent;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
public class RealContentImpl implements Content {
private byte[] bytes;
private boolean ready = false;
public RealContentImpl(String url) {
doParse(url);
}
private byte[] doParse(String urlName) {
System.out.println(Thread.currentThread().getName() + " doParse " + urlName + " begin...");
URL url = null;
DataInputStream input = null;
byte[] bytesTmp = new byte[1];
try {
url = new URL(urlName);
input = new DataInputStream(url.openStream());
int index = 0;
while(true) {
int c = input.readUnsignedByte();
if(bytesTmp.length <= index) {
byte[] largerBuffer = new byte[bytesTmp.length * 2];
System.arraycopy(bytesTmp, 0, largerBuffer, 0, index);
bytesTmp = largerBuffer;
}
bytesTmp[index++] = (byte)c;
}
} catch (EOFException e) {
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if(input != null) {
try {
input.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
input = null;
}
if(url != null) {
url = null;
}
}
bytes = new byte[bytesTmp.length];
System.arraycopy(bytesTmp, 0, bytes, 0, bytesTmp.length);
ready = true;
return bytes;
}
@Override
public byte[] getBytes() {
return bytes;
}
public void setBytes(byte[] bytes) {
this.bytes = bytes;
}
public boolean isReady() {
return ready;
}
public void setReady(boolean ready) {
this.ready = ready;
}
}
package com.metarnet.FuturePattern.URLContent;
public class Retriver {
public Content getContent(final String url) throws InterruptedException {
System.out.println("request " + url + " begin...");
final VirtualContentImpl content = new VirtualContentImpl();
new Thread() {
@Override
public void run() {
RealContentImpl real = new RealContentImpl(url);
content.setReal(real);
}
}.start();
return content;
}
}
package com.metarnet.FuturePattern.URLContent;
public class VirtualContentImpl implements Content {
private boolean ready = false;
private RealContentImpl real;
@Override
public byte[] getBytes() {
synchronized(this) {
if(!ready) {
try {
wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return real.getBytes();
}
}
public RealContentImpl getReal() {
return real;
}
public synchronized void setReal(RealContentImpl real) {
if(real.isReady()) {
this.real = real;
ready = true;
this.notifyAll();
}
}
}
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