Java multi -threaded

 This post last edited by the huayiluo on 2013-10-04 14:54:35

along, I hope to do a feature is

For example, I have a lot of pictures sheets.

http://www.xx.com/1.jpg
http://www.xx.com/2.jpg
http://www.xx.com/3.jpg
http://www.xx.com/4.jpg
http://www.xx.com/5.jpg
.................. 100.jpg

names of these pictures are digital growth .

I now want to do is : two threads. While to download.

class MultiDownloadThread implements Runnable{
  private int index;
  public void run() {
  		// TODO Auto-generated method stub
  		synchronized (this) {
  			index++;
                  download(index);//这个方法，里面会有堵塞，
  		}
  
  }
  
  class Demo{
  public static void main(String []args){
  MultiDownloadThread t=new MultiDownloadThread();
  new Thread(t).start();
  new Thread(t).start();
  }
  }
  

want this, start two threads , but you can download 2 . Respectively to download
1.jpg, 2.jpg;
3.jpg, 4.jpg;
5.jpg, 6.jpg;

but not, if the thread enters a download, the second thread must wait because the synchronized block , download pictures to wait for the network .

question how done , sync to get index + +, then the synchronized block (synchronized) start out download (index);




The general requirement is that the two threads acquire synchronization logo (index + +), and then were to perform a blocking download method (download (index))
------ Solution ----- ---------------------------------------
In fact, I did not understand the case of multi-core how to make two threads to run simultaneously


------ For reference only ---------------------------------- -----
should not ah , the landlord would like to achieve this functionality before I specifically did .
multithreaded indeed a little faster than the single-threaded , but just a little bit faster , because the most important thing is to see bandwidth. . .
landlord only needs to index the entire process without the need for locking locked . .
landlord to set up a
synchronized int addIndex () {
return index + +;
}
methods
public void run () {
/ / TODO Auto-generated method stub
int i = addIndex ();
download (i) ;/ / This should be a
}
------ For reference only ----------------------------- ----------


thanks , has been the question , thank you. Solved