Java多线程查找指定文件夹下包含指定关键字的文件数量（线程池版）

最新推荐文章于 2021-06-19 13:27:03 发布

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最新推荐文章于 2021-06-19 13:27:03 发布

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分类专栏： Programing Language 文章标签： java 多线程并发

本文链接：https://blog.youkuaiyun.com/gyn18744026959/article/details/71190987

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该博客演示了如何使用Java多线程和线程池查找指定文件夹（F:\C++ Project）下包含特定关键字（namespace）的文件数量。通过创建`ThreadPoolTest`类，利用`ExecutorService`和`Callable`接口实现递归搜索，最后输出匹配的文件数量及线程池的最大大小。

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import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadPoolExecutor;

public class ThreadPoolTest {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		File directory = new File("F:\\C++ Project");
		String keyWords = "namespace";
		ExecutorService pool = Executors.newCachedThreadPool();
		Future<Integer> future = pool.submit(new PoolMatchCounter(directory, keyWords, pool));
		try {
			System.out.println(future.get() + " files match");
		} catch (InterruptedException | ExecutionException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		pool.shutdown();
		ThreadPoolExecutor executor = (ThreadPoolExecutor)pool;
		System.out.println("Largest Pool Size: " + executor.getLargestPoolSize());
	}

}

class PoolMatchCounter implements Callable<Integer>{
	
	private File directory;
	private String keyWords;
	private ExecutorService pool;
	
	public PoolMatchCounter(File directory, String keyWords, ExecutorService pool) {
		super();
		this.directory = directory;
		this.keyWords = keyWords;
		this.pool = pool;
	}

	@Override
	public Integer call() throws Exception {
		// TODO Auto-generated method stub
		File[] files = directory.listFiles();
		List<Future<Integer>> result = new ArrayList<>();
		int count = 0;
		for(File f : files){
			if(f.isDirectory()){
				Future<Integer> future = pool.submit(new PoolMatchCounter(f, keyWords, pool));
				result.add(future);
			}else{
				if(search(f)) ++count;
			}
		}
		
		for(Future<Integer> f : result){
			count += f.get();
		}
		return count;
	}
	
	
	public boolean search(File f) throws FileNotFoundException{
		try(Scanner in = new Scanner(f)){
			boolean found = false;
			while(!found&in.hasNextLine()){
				String line = in.nextLine();
				if(line.contains(keyWords)){
					found = true;
				}
			}
			return found;
		}
	}
	
}