java多线程批量读取文件( 八)--读写分离

package com.net.thread.future;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

/**
 * @author
 * @Time：2017年8月16日 下午5:26:37
 * @version 1.0
 * @description
 */
public class CallableDemo3 {

    final static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    public static void main(String[] args)
    {
        File f = new File("C://Users//LENOVO//Desktop//file");
        // 文件总数
        final List<File> filePathsList = new ArrayList<File>();
        File[] filePaths = f.listFiles();
        for (File s : filePaths) {
            filePathsList.add(s);
        }

        CountDownLatch latch = new CountDownLatch(filePathsList.size());
        ExecutorService pool = Executors.newFixedThreadPool(10);

        BlockingQueue<Future<Map<String, FileInputStream>>> queue =
                new ArrayBlockingQueue<Future<Map<String, FileInputStream>>>(100);

        System.out.println("-------------文件读、写任务开始时间：" + sdf.format(new Date()));
        for (int i = 0; i < filePathsList.size(); i++) {
            File temp = filePathsList.get(i);
            Future<Map<String, FileInputStream>> future = pool.submit(new MyCallableProducer(latch, temp));
            queue.add(future);

            pool.execute(new MyCallableConsumer(queue));
        }

        try {
            latch.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("-------------文件读、写任务结束时间：" + sdf.format(new Date()));
         pool.shutdownNow();
    }

    // 文件读线程
    static class MyCallableProducer implements Callable<Map<String, FileInputStream>>
    {
        private CountDownLatch latch;
        private File file;
        private FileInputStream fis = null;
        private Map<String, FileInputStream> fileMap = new HashMap<String, FileInputStream>();

        public MyCallableProducer(CountDownLatch latch, File file)
        {
            this.latch = latch;
            this.file = file;
        }

        @Override
        public Map<String, FileInputStream> call() throws Exception
        {
            System.out.println(Thread.currentThread().getName() + " 线程开始读取文件 ：" + file.getName() + " ,时间为 "+ sdf.format(new Date()));
            fis = new FileInputStream(file);
            fileMap.put(file.getName(), fis);
             doWork();
            System.out.println(Thread.currentThread().getName() + " 线程读取文件 ：" + file.getName() + " 完毕"  + " ,时间为 "+ sdf.format(new Date()));
            latch.countDown();
            return fileMap;
        }

        private void doWork()
        {
　　　　　　　　//此方法可以添加一些业务逻辑，比如包装pojo等等操作，返回的值可以是任何类型
            Random rand = new Random();
            int time = rand.nextInt(10) * 1000;
            try {
                Thread.sleep(time);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    // 文件写线程
    static class MyCallableConsumer implements Runnable
    {
        private String fileName = "";
        private BlockingQueue<Future<Map<String, FileInputStream>>> queue;
        private FileInputStream fis = null;
        private File dirFile = null;

        private BufferedReader br = null;
        private InputStreamReader isr = null;
        private FileWriter fw = null;
        private BufferedWriter bw = null;

        public MyCallableConsumer(BlockingQueue<Future<Map<String, FileInputStream>>> queue2)
        {
            this.queue = queue2;
        }

        @Override
        public void run()
        {
            try {
                Future<Map<String, FileInputStream>> future = queue.take();
                Map<String, FileInputStream> map = future.get();

                Set<String> set = map.keySet();
                for (Iterator<String> iter = set.iterator(); iter.hasNext();) {

                    fileName = iter.next().toString();
                    fis = map.get(fileName);

                    System.out.println(Thread.currentThread().getName() + " 线程开始写文件 ：" + fileName  + " ,时间为 "+ sdf.format(new Date()));
                    try {
                        isr = new InputStreamReader(fis, "utf-8");
                        br = new BufferedReader(isr);

                        dirFile = new File("d:" + File.separator + "gc3" + File.separator + fileName);
                        fw = new FileWriter(dirFile);
                        bw = new BufferedWriter(fw);

                        String data = "";
                        bw.write("+++++++++++++" + Thread.currentThread().getName() + " 线程开始写文件++++++++++++");
                        while ((data = br.readLine()) != null) {
                            bw.write(data + "\r");
                        }
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    } finally {
                        try {
                            bw.close();
                            br.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (ExecutionException e) {
                e.printStackTrace();
            }
        }
    }

}

说明：

1、其实构思很简单，阻塞队列是线程安全的，那么我多线程就用阻塞队列，这样可以保证每个写线程拿到的具体内容不同，不会导致重复写数据；

2、我使用异步线程进行读写，而非同步线程，这样有助于提升整体读、写性能。

3、CountDownLatch是信号灯，功能类似于join()方法，当然也可以使用CyclicBarrier