(一)單線程遞歸方式

package?com.taobao.test;?import?java.io.File;?public?class?TotalFileSizeSequential?{?????public?static?String?fileName?=?"C:\\Documents?and?Settings\\Administrator\\桌面\\monkeytalk";?????//?遞歸方式?計算文件的大小?????private?long?getTotalSizeOfFilesInDir(final?File?file)?{?????????if?(file.isFile())?????????????return?file.length();?????????final?File[]?children?=?file.listFiles();?????????long?total?=?0;?????????if?(children?!=?null)?????????????for?(final?File?child?:?children)?????????????????total?+=?getTotalSizeOfFilesInDir(child);?????????return?total;?????}?????public?static?void?main(final?String[]?args)?{?????????final?long?start?=?System.nanoTime();?????????final?long?total?=?new?TotalFileSizeSequential()?????????????????.getTotalSizeOfFilesInDir(new?File(fileName));?????????final?long?end?=?System.nanoTime();?????????System.out.println("Total?Size:?"?+?total);?????????System.out.println("Time?taken:?"?+?(end?-?start)?/?1.0e9);?????}?}

(二)使用Executors.newFixedThreadPool和callable 多線程實現(xiàn)

package?com.taobao.test;?import?java.io.File;?import?java.util.ArrayList;?import?java.util.Collections;?import?java.util.List;?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.TimeUnit;?import?java.util.concurrent.TimeoutException;?public?class?ConcurrentTotalFileSize?{?????public?static?final?String?fileName?=?"C:\\Documents?and?Settings\\Administrator\\桌面\\monkeytalk";?????class?SubDirectoriesAndSize?{?????????final?public?long?size;?????????final?public?List<File>?subDirectories;?????????public?SubDirectoriesAndSize(final?long?totalSize,?????????????????final?List<File>?theSubDirs)?{?????????????size?=?totalSize;?????????????subDirectories?=?Collections.unmodifiableList(theSubDirs);?????????}?????}?????private?SubDirectoriesAndSize?getTotalAndSubDirs(final?File?file)?{?????????long?total?=?0;?????????final?List<File>?subDirectories?=?new?ArrayList<File>();?????????if?(file.isDirectory())?{?????????????final?File[]?children?=?file.listFiles();?????????????if?(children?!=?null)?????????????????for?(final?File?child?:?children)?{?????????????????????if?(child.isFile())?????????????????????????total?+=?child.length();?????????????????????else?????????????????????????subDirectories.add(child);?????????????????}?????????}?????????return?new?SubDirectoriesAndSize(total,?subDirectories);?????}?????private?long?getTotalSizeOfFilesInDir(final?File?file)?????????????throws?InterruptedException,?ExecutionException,?TimeoutException?{?????????final?ExecutorService?service?=?Executors.newFixedThreadPool(100);?????????try?{?????????????long?total?=?0;?????????????final?List<File>?directories?=?new?ArrayList<File>();?????????????directories.add(file);?????????????while?(!directories.isEmpty())?{?????????????????final?List<Future<SubDirectoriesAndSize>>?partialResults?=?new?ArrayList<Future<SubDirectoriesAndSize>>();?????????????????for?(final?File?directory?:?directories)?{?????????????????????partialResults.add(service?????????????????????????????.submit(new?Callable<SubDirectoriesAndSize>()?{?????????????????????????????????public?SubDirectoriesAndSize?call()?{?????????????????????????????????????return?getTotalAndSubDirs(directory);?????????????????????????????????}?????????????????????????????}));?????????????????}?????????????????directories.clear();?????????????????for?(final?Future<SubDirectoriesAndSize>?partialResultFuture?:?partialResults)?{?????????????????????final?SubDirectoriesAndSize?subDirectoriesAndSize?=?partialResultFuture?????????????????????????????.get(100,?TimeUnit.SECONDS);?????????????????????directories.addAll(subDirectoriesAndSize.subDirectories);?????????????????????total?+=?subDirectoriesAndSize.size;?????????????????}?????????????}?????????????return?total;?????????}?finally?{?????????????service.shutdown();?????????}?????}?????public?static?void?main(final?String[]?args)?throws?InterruptedException,?????????????ExecutionException,?TimeoutException?{?????????final?long?start?=?System.nanoTime();?????????final?long?total?=?new?ConcurrentTotalFileSize()?????????????????.getTotalSizeOfFilesInDir(new?File(fileName));?????????final?long?end?=?System.nanoTime();?????????System.out.println("Total?Size:?"?+?total);?????????System.out.println("Time?taken:?"?+?(end?-?start)?/?1.0e9);?????}?}

(三)使用Executors.newFixedThreadPool和callable 多線程的另外一種實現(xiàn)

package?com.taobao.test;??import?java.io.File;?import?java.util.ArrayList;?import?java.util.List;?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.TimeUnit;?import?java.util.concurrent.TimeoutException;?public?class?NaivelyConcurrentTotalFileSize?{?????public?static?String?fileName?=?"C:\\Documents?and?Settings\\Administrator\\桌面\\monkeytalk";?????private?long?getTotalSizeOfFilesInDir(final?ExecutorService?service,?????????????final?File?file)?throws?InterruptedException,?ExecutionException,?????????????TimeoutException?{?????????if?(file.isFile())?????????????return?file.length();?????????long?total?=?0;?????????final?File[]?children?=?file.listFiles();?????????if?(children?!=?null)?{?????????????final?List<Future<Long>>?partialTotalFutures?=?new?ArrayList<Future<Long>>();?????????????for?(final?File?child?:?children)?{?????????????????partialTotalFutures.add(service.submit(new?Callable<Long>()?{?????????????????????public?Long?call()?throws?InterruptedException,?????????????????????????????ExecutionException,?TimeoutException?{?????????????????????????return?getTotalSizeOfFilesInDir(service,?child);?????????????????????}?????????????????}));?????????????}?????????????for?(final?Future<Long>?partialTotalFuture?:?partialTotalFutures)?????????????????total?+=?partialTotalFuture.get(100,?TimeUnit.SECONDS);?????????}?????????return?total;?????}?????private?long?getTotalSizeOfFile(final?String?fileName)?????????????throws?InterruptedException,?ExecutionException,?TimeoutException?{?????????final?ExecutorService?service?=?Executors.newFixedThreadPool(100);?????????try?{?????????????return?getTotalSizeOfFilesInDir(service,?new?File(fileName));?????????}?finally?{?????????????service.shutdown();?????????}?????}?????public?static?void?main(final?String[]?args)?throws?InterruptedException,?????????????ExecutionException,?TimeoutException?{?????????final?long?start?=?System.nanoTime();?????????final?long?total?=?new?NaivelyConcurrentTotalFileSize()?????????????????.getTotalSizeOfFile(fileName);?????????final?long?end?=?System.nanoTime();?????????System.out.println("Total?Size:?"?+?total);?????????System.out.println("Time?taken:?"?+?(end?-?start)?/?1.0e9);?????}?}

(四)使用CountDownLatch和AtomicLong實現(xiàn)多線程下的并發(fā)控制

package?com.taobao.test;?import?java.io.File;?import?java.util.concurrent.CountDownLatch;?import?java.util.concurrent.ExecutorService;?import?java.util.concurrent.Executors;?import?java.util.concurrent.TimeUnit;?import?java.util.concurrent.atomic.AtomicLong;?public?class?ConcurrentTotalFileSizeWLatch?{?????private?ExecutorService?service;?????final?private?AtomicLong?pendingFileVisits?=?new?AtomicLong();?????final?private?AtomicLong?totalSize?=?new?AtomicLong();?????final?private?CountDownLatch?latch?=?new?CountDownLatch(1);?????public?static?String?fileName?=?"C:\\Documents?and?Settings\\Administrator\\桌面\\monkeytalk";?????private?void?updateTotalSizeOfFilesInDir(final?File?file)?{?????????long?fileSize?=?0;?????????if?(file.isFile())?????????????fileSize?=?file.length();?????????else?{?????????????final?File[]?children?=?file.listFiles();?????????????if?(children?!=?null)?{?????????????????for?(final?File?child?:?children)?{?????????????????????if?(child.isFile())?????????????????????????fileSize?+=?child.length();?????????????????????else?{?????????????????????????pendingFileVisits.incrementAndGet();?????????????????????????service.execute(new?Runnable()?{?????????????????????????????public?void?run()?{?????????????????????????????????updateTotalSizeOfFilesInDir(child);?????????????????????????????}?????????????????????????});?????????????????????}?????????????????}?????????????}?????????}?????????totalSize.addAndGet(fileSize);?????????if?(pendingFileVisits.decrementAndGet()?==?0)?????????????latch.countDown();?????}?????private?long?getTotalSizeOfFile(final?String?fileName)?????????????throws?InterruptedException?{?????????service?=?Executors.newFixedThreadPool(100);?????????pendingFileVisits.incrementAndGet();?????????try?{?????????????updateTotalSizeOfFilesInDir(new?File(fileName));?????????????latch.await(100,?TimeUnit.SECONDS);?????????????return?totalSize.longValue();?????????}?finally?{?????????????service.shutdown();?????????}?????}?????public?static?void?main(final?String[]?args)?throws?InterruptedException?{?????????final?long?start?=?System.nanoTime();?????????final?long?total?=?new?ConcurrentTotalFileSizeWLatch()?????????????????.getTotalSizeOfFile(fileName);?????????final?long?end?=?System.nanoTime();?????????System.out.println("Total?Size:?"?+?total);?????????System.out.println("Time?taken:?"?+?(end?-?start)?/?1.0e9);?????}?}

(五)使用BlockingQueue和AtomicLong的實現(xiàn)

package?com.taobao.test;?import?java.io.File;?import?java.util.concurrent.ArrayBlockingQueue;?import?java.util.concurrent.BlockingQueue;?import?java.util.concurrent.ExecutorService;?import?java.util.concurrent.Executors;?import?java.util.concurrent.TimeUnit;?import?java.util.concurrent.atomic.AtomicLong;?public?class?ConcurrentTotalFileSizeWQueue?{?????public?static?String?fileName?=?"C:\\Documents?and?Settings\\Administrator\\桌面\\monkeytalk";??????private?ExecutorService?service;?????final?private?BlockingQueue<Long>?fileSizes?=?new?ArrayBlockingQueue<Long>(?????????????500);?????final?AtomicLong?pendingFileVisits?=?new?AtomicLong();?????private?void?startExploreDir(final?File?file)?{?????????pendingFileVisits.incrementAndGet();?????????service.execute(new?Runnable()?{?????????????public?void?run()?{?????????????????exploreDir(file);?????????????}?????????});?????}?????private?void?exploreDir(final?File?file)?{?????????long?fileSize?=?0;?????????if?(file.isFile())?????????????fileSize?=?file.length();?????????else?{?????????????final?File[]?children?=?file.listFiles();?????????????if?(children?!=?null)?????????????????for?(final?File?child?:?children)?{?????????????????????if?(child.isFile())?????????????????????????fileSize?+=?child.length();?????????????????????else?{?????????????????????????startExploreDir(child);?????????????????????}?????????????????}?????????}?????????try?{?????????????fileSizes.put(fileSize);?????????}?catch?(Exception?ex)?{?????????????throw?new?RuntimeException(ex);?????????}?????????pendingFileVisits.decrementAndGet();?????}?????private?long?getTotalSizeOfFile(final?String?fileName)?????????????throws?InterruptedException?{?????????service?=?Executors.newFixedThreadPool(100);?????????try?{?????????????startExploreDir(new?File(fileName));?????????????long?totalSize?=?0;?????????????while?(pendingFileVisits.get()?>?0?||?fileSizes.size()?>?0)?{?????????????????final?Long?size?=?fileSizes.poll(10,?TimeUnit.SECONDS);?????????????????totalSize?+=?size;?????????????}?????????????return?totalSize;?????????}?finally?{?????????????service.shutdown();?????????}?????}?????public?static?void?main(final?String[]?args)?throws?InterruptedException?{?????????final?long?start?=?System.nanoTime();?????????final?long?total?=?new?ConcurrentTotalFileSizeWQueue()?????????????????.getTotalSizeOfFile(fileName);?????????final?long?end?=?System.nanoTime();?????????System.out.println("Total?Size:?"?+?total);?????????System.out.println("Time?taken:?"?+?(end?-?start)?/?1.0e9);?????}?}

(六)使用jdk7的ForkJoin來實現(xiàn)

package?com.taobao.test;?import?java.io.File;?import?java.util.ArrayList;?import?java.util.List;?import?java.util.concurrent.ForkJoinPool;?import?java.util.concurrent.ForkJoinTask;?import?java.util.concurrent.RecursiveTask;?public?class?FileSize?{?????private?final?static?ForkJoinPool?forkJoinPool?=?new?ForkJoinPool();?????public?static?String?fileName?=?"C:\\Documents?and?Settings\\Administrator\\桌面\\monkeytalk";??????private?static?class?FileSizeFinder?extends?RecursiveTask<Long>?{?????????final?File?file;?????????public?FileSizeFinder(final?File?theFile)?{?????????????file?=?theFile;?????????}?????????@Override?????????public?Long?compute()?{?????????????long?size?=?0;?????????????if?(file.isFile())?{?????????????????size?=?file.length();?????????????}?else?{?????????????????final?File[]?children?=?file.listFiles();?????????????????if?(children?!=?null)?{?????????????????????List<ForkJoinTask<Long>>?tasks?=?new?ArrayList<ForkJoinTask<Long>>();?????????????????????for?(final?File?child?:?children)?{?????????????????????????if?(child.isFile())?{?????????????????????????????size?+=?child.length();?????????????????????????}?else?{?????????????????????????????tasks.add(new?FileSizeFinder(child));?????????????????????????}?????????????????????}?????????????????????for?(final?ForkJoinTask<Long>?task?:?invokeAll(tasks))?{?????????????????????????size?+=?task.join();?????????????????????}?????????????????}?????????????}?????????????return?size;?????????}?????}?????public?static?void?main(final?String[]?args)?{?????????final?long?start?=?System.nanoTime();?????????final?long?total?=?forkJoinPool.invoke(new?FileSizeFinder(new?File("/home")));?????????final?long?end?=?System.nanoTime();?????????System.out.println("Total?Size:?"?+?total);?????????System.out.println("Time?taken:?"?+?(end?-?start)?/?1.0e9);?????}?}

? ??? Java?? ?? ??? ?? ??? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!