阻塞队列BlockingQueue

1.知识点

2.用阻塞队列实现生产者消费者的例子

package src.corejava.v1ch14.blockingQueue;import java.io.*;import java.util.*;import java.util.concurrent.*;/** * @version 1.02 2015-06-21 * @author Cay Horstmann */public class BlockingQueueTest{   private static final int FILE_QUEUE_SIZE = 10;   private static final int SEARCH_THREADS = 100;   private static final File DUMMY = new File("");   private static BlockingQueue<File> queue = new ArrayBlockingQueue<>(FILE_QUEUE_SIZE);   public static void main(String[] args)   {      try (Scanner in = new Scanner(System.in))       {         System.out.print("Enter base directory (e.g. /opt/jdk1.8.0/src): ");         String directory = in.nextLine();         System.out.print("Enter keyword (e.g. volatile): ");         String keyword = in.nextLine();                   Runnable enumerator = () -> {            try            {               enumerate(new File(directory));               queue.put(DUMMY);               //因为队列是先进先出所以这里可以做一个标识如果最后消费者取到的是这个标识，那么认为已经消费完毕，程序结束            }            catch (InterruptedException e)            {            }                     };                  new Thread(enumerator).start();         for (int i = 1; i <= SEARCH_THREADS; i++) {            Runnable searcher = () -> {               try               {                  boolean done = false;                  while (!done)                  {                     File file = queue.take();                     if (file == DUMMY)                     {                        queue.put(file);                        done = true;                     }                     else search(file, keyword);                  }               }               catch (IOException e)               {                  e.printStackTrace();               }               catch (InterruptedException e)               {               }                           };            new Thread(searcher).start();         }      }   }      /**    * Recursively enumerates all files in a given directory and its subdirectories.    * @param directory the directory in which to start    */   public static void enumerate(File directory) throws InterruptedException   {      File[] files = directory.listFiles();      for (File file : files)      {         if (file.isDirectory()) enumerate(file);         else queue.put(file);      }   }      /**    * Searches a file for a given keyword and prints all matching lines.    * @param file the file to search    * @param keyword the keyword to search for    */   public static void search(File file, String keyword) throws IOException   {      try (Scanner in = new Scanner(file, "UTF-8"))//这种写法会自动关闭流      {         int lineNumber = 0;         while (in.hasNextLine())         {            lineNumber++;            String line = in.nextLine();            if (line.contains(keyword))                System.out.printf("%s:%d:%s%n", file.getPath(), lineNumber, line);         }      }   }}