JAVA读取文件夹大小

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);
}
}

package com.sunsheen.jfids.studio.monitor.utils.local;import java.io.File;
import java.math.BigDecimal;
import java.math.RoundingMode;
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;/**
* 得到指定文件夹大小（使用CountDownLatch和AtomicLong实现多线程下的并发控制）
* @author WangSong
*
*/
public class FileUtil {
private ExecutorService service;
final private AtomicLong pendingFileVisits = new AtomicLong();
final private AtomicLong totalSize = new AtomicLong();
final private CountDownLatch latch = new CountDownLatch(1);
//更新文件总大小（多线程）
private void updateTotalSizeOfFilesInDir(final File file) {
long fileSize = 0;//初始化文件大小 //文件，直接返回大小
if (file.isFile())
fileSize = file.length();
//文件夹，遍历所有文件总大小
else {
final File[] children = file.listFiles();
if(null == children){
totalSize.set(0);
return;
}
for (final File child : children) {
//文件：直接加当前文件的大小
if (child.isFile())
fileSize += child.length();
//文件夹：遍历里面的文件的大小
else {
pendingFileVisits.incrementAndGet();
service.execute(new Runnable() {
public void run() {
updateTotalSizeOfFilesInDir(child);
}
});
}
}
} totalSize.addAndGet(fileSize);
if (pendingFileVisits.decrementAndGet() == 0)
latch.countDown();
} /**
* 得到指定文件的大小
* @param fileName 文件名（全路径）
* @return 文件夹大小（M）
* @throws InterruptedException
*/
public double getTotalSizeOfFile(final String fileName){
service = Executors.newFixedThreadPool(100);//初始化线程池
pendingFileVisits.incrementAndGet();//增加当前值1
double result = 0;//初始化结果
try {
updateTotalSizeOfFilesInDir(new File(fileName));
latch.await(100, TimeUnit.SECONDS);//当前线程等待，直到锁存器计数到0
//将k转换成m
long resultK = totalSize.longValue();
BigDecimal bdK = new BigDecimal(resultK);
BigDecimal bdM = bdK.divide(new BigDecimal(1024 * 1024)).setScale(5, RoundingMode.HALF_UP);//保留5位小数
result = bdM.doubleValue();
}catch (InterruptedException e) {
e.printStackTrace();
}finally {
service.shutdown();
}
return result;
}}

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);
}
}