使用BlockingQueue在给定的某个文件夹下查找给定的关键字keywords

在给定的某个文件夹下查找给定的关键字keywords

程序源于Java核心技术（卷I）第8版 基础知识（中文版） 

作者：Cay S.Horstmann,Gray Cornell ，

第14章多线程中的第14.6节阻塞队列，源码如下：

package v1ch14.BlockingQueueTest;import java.io.*;import java.util.*;import java.util.concurrent.*;/** * @version 1.0 2004-08-01 * @author Cay Horstmann */public class BlockingQueueTest{   public static void main(String[] args)   {      Scanner in = new Scanner(System.in);      System.out.print("Enter base directory (e.g. /usr/local/jdk1.6.0/src): ");      String directory = in.nextLine();      System.out.println("************ directory = "+directory);      System.out.print("Enter keyword (e.g. volatile): ");      String keyword = in.nextLine();      System.out.println("************ keyword = "+keyword);            final int FILE_QUEUE_SIZE = 10;      final int SEARCH_THREADS = 100;      BlockingQueue<File> queue = new ArrayBlockingQueue<File>(FILE_QUEUE_SIZE);      FileEnumerationTask enumerator = new FileEnumerationTask(queue, new File(directory));      new Thread(enumerator).start();      for (int i = 1; i <= SEARCH_THREADS; i++)         new Thread(new SearchTask(queue, keyword)).start();   }}/** * This task enumerates all files in a directory and its subdirectories. */class FileEnumerationTask implements Runnable{   /**    * Constructs a FileEnumerationTask.    * @param queue the blocking queue to which the enumerated files are added    * @param startingDirectory the directory in which to start the enumeration    */   public FileEnumerationTask(BlockingQueue<File> queue, File startingDirectory)   {      this.queue = queue;      this.startingDirectory = startingDirectory;   }   public void run()   {      try      {         enumerate(startingDirectory);         queue.put(DUMMY);      }      catch (InterruptedException e)      {      }   }   /**    * Recursively enumerates all files in a given directory and its subdirectories    * @param directory the directory in which to start    */   public void enumerate(File directory) throws InterruptedException   {      File[] files = directory.listFiles();      for (File file : files)      {         if (file.isDirectory()) enumerate(file);         else queue.put(file);      }   }   public static File DUMMY = new File("");   private BlockingQueue<File> queue;   private File startingDirectory;}/** * This task searches files for a given keyword. */class SearchTask implements Runnable{   /**    * Constructs a SearchTask.    * @param queue the queue from which to take files    * @param keyword the keyword to look for    */   public SearchTask(BlockingQueue<File> queue, String keyword)   {      this.queue = queue;      this.keyword = keyword;   }   public void run()   {      try      {         boolean done = false;         while (!done)         {            File file = queue.take();            if (file == FileEnumerationTask.DUMMY)            {               queue.put(file);               done = true;            }            else search(file);         }      }      catch (IOException e)      {         e.printStackTrace();      }      catch (InterruptedException e)      {      }   }   /**    * Searches a file for a given keyword and prints all matching lines.    * @param file the file to search    */   public void search(File file) throws IOException   {      Scanner in = new Scanner(new FileInputStream(file));      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);      }      in.close();   }   private BlockingQueue<File> queue;   private String keyword;}

运行如下：

Enter base directory (e.g. /usr/local/jdk1.6.0/src): D:\all_install\MyEclipse_install\Workspace1\tesst\src\v1ch14
************ directory = D:\all_install\MyEclipse_install\Workspace1\tesst\src\v1ch14
Enter keyword (e.g. volatile): public
************ keyword = public

D:\all_install\MyEclipse_install\Workspace1\tesst\src\v1ch14\AlgorithmAnimation\AlgorithmAnimation.java:15:public class AlgorithmAnimation
D:\all_install\MyEclipse_install\Workspace1\tesst\src\v1ch14\AlgorithmAnimation\AlgorithmAnimation.java:17:   public static void main(String[] args)
D:\all_install\MyEclipse_install\Workspace1\tesst\src\v1ch14\AlgorithmAnimation\AlgorithmAnimation.java:21:            public void run()
D:\all_install\MyEclipse_install\Workspace1\tesst\src\v1ch14\AlgorithmAnimation\AlgorithmAnimation.java:37:   public AnimationFrame()
D:\all_install\MyEclipse_install\Workspace1\tesst\src\v1ch14\AlgorithmAnimation\AlgorithmAnimation.java:47:            public void actionPerformed(ActionEvent event)
D:\all_install\MyEclipse_install\Workspace1\tesst\src\v1ch14\UnsynchBankTest\UnsynchBankTest.java:8:public class UnsynchBankTest

............部分结果

看过代码后，对查找某文件夹下的文件中的关键字，有了一定的思路，如下：

1.查找给定文件夹下的所有文件，并放入队列中

2.根据输入的关键字，循环查找某个文件中包含的关键字行

代码通过测试，毕竟是大牛写的，我们小辈只有学习的份，可以直接copy，运行，祝大家好运！