groovy多線程

Question

我是groovy/grails的新手。

如何爲此代碼實現線程。有2500個網址，這需要幾個小時的時間來檢查每個網址。

，所以我決定實現多線程此：

這裏是我的示例代碼：

def urls = [ 
    "http://www.wordpress.com", 
    "http://67.192.103.225/QRA.Public/" , 
    "http://www.subaru.com", 
    "http://baldwinfilter.com/products/start.html" 
] 

def up = urls.collect { ur -> 
    try { 
     def url = new URL(ur) 
     def connection = url.openConnection() 
     if (connection.responseCode == 200) { 
      return true 
     } else { 
      return false 
     } 
    } catch (Exception e) { 
     return false 
    } 
} 

對於這個代碼我需要實現多線程。
任何人都可以向我推薦代碼。

在此先感謝，
sri。

Answer 1

See the Groovy docs舉例說明如何使用ExecutorService來做你想做的事。

Answer 2

我會看看Groovy Parallel Systems庫。特別是我認爲Parallel collections部分會很有用。

看着文檔，我相信collectParallel是一個直接替代collect（銘記關於副作用的明顯警告）。以下工作適合我：

def urls = [ 
    "http://www.wordpress.com", 
    "http://www.subaru.com", 
    "http://baldwinfilter.com/products/start.html" 
] 
Parallelizer.doParallel { 
    def up = urls.collectParallel { ur -> 
     try { 
      def url = new URL(ur) 
      def connection = url.openConnection() 
      if (connection.responseCode == 200) { 
       return true 
      } else { 
       return false 
      } 
     } catch (Exception e) { 
      return false 
     } 
    } 
    println up 
} 

Answer 3

您可以使用它來檢查單獨的線程中的URL。

class URLReader implements Runnable 
{ 
    def valid 
    def url 

    URLReader(url) { 
     this.url = url 
    } 

    void run() { 
     try { 
      def connection = url.toURL().openConnection() 
      valid = (connection.responseCode == 200) as Boolean 
     } catch (Exception e) { 
      println e.message 
      valid = Boolean.FALSE 
     } 
    } 
} 
def reader = new URLReader("http://www.google.com") 
new Thread(reader).start() 
while (reader.valid == null) 
{ 
    Thread.sleep(500) 
} 
println "valid: ${reader.valid}" 

注：有效屬性將爲null，Boolean.TRUE或Boolean.FALSE。您需要等待一段時間才能讓所有線程有機會打開連接。根據您檢查的URL數量，您最終會達到您可以切實處理的線索數量/連接數量的限制，因此應該按照適當大小的批量檢查URL。

Answer 4

這是我如何實現：

class ValidateLinks extends Thread{ 
    def valid 
    def url 

    ValidateLinks(url) { 
     this.url = url 
    } 

    void run() { 
     try { 
      def connection = url.toURL().openConnection() 
     connection.setConnectTimeout(5000) 
      valid = (connection.responseCode == 200) as Boolean 
     } catch (Exception e) { 
      println url + "-" + e.message 
      valid = Boolean.FALSE 
     } 
    } 
} 

def threads = []; 
urls.each { ur -> 
def reader = new ValidateLinks(ur.site_url) 
reader.start() 
threads.add(reader); 
} 

while (threads.size() > 0) { 

     for(int i =0; i < threads.size();i++) { 
       def tr = threads.get(i); 
       if (!tr.isAlive()) { 
         println "URL : " + tr.url + "Valid " + tr.valid 
         threads.remove(i); 
         i--; 

       } 
     } 
} 

Answer 5

我覺得這種方式是實現非常簡單。

---

import java.util.concurrent.* 

//Thread number 
THREADS = 100 
pool = Executors.newFixedThreadPool(THREADS) 
defer = { c -> pool.submit(c as Callable) } 

def urls = [ 
    "http://www.wordpress.com", 
    "http://www.subaru.com", 
] 

def getUrl = { url -> 
    def connection = url.openConnection() 
    if (connection.responseCode == 200) { 
    return true 
    } else { 
    return false 
    } 
} 


def up = urls.collect { ur -> 
    try { 
     def url = new URL(ur) 
    defer{ getUrl(url) }.get() 
    } catch (Exception e) { 
     return false 
    } 
} 

println up 
pool.shutdown()