Java NIO复制文件功能

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1. package com.ghb.crp.file;   2.   3. import java.io.BufferedInputStream;   4. import java.io.BufferedOutputStream;   5. import java.io.File;   6. import java.io.FileInputStream;   7. import java.io.FileOutputStream;   8. import java.nio.ByteBuffer;   9. import java.nio.channels.FileChannel;   10.   11. public class FileCopy {   12.     public static String src = "f://ss.rmvb";   13.     public static String dist = "f://ss2.rmvb";   14.   15.     /**  16.      * @param args  17.      */  18.     public static void main(String[] args) {   19.         long start = System.currentTimeMillis();   20.         copyNew();   21.         long end = System.currentTimeMillis();   22.         System.out.println("nio 用时： " + (end - start));   23.   24.         long start2 = System.currentTimeMillis();   25.         copyOld();   26.         end = System.currentTimeMillis();   27.         System.out.println("io 用时： " + (end - start2));   28.     }   29.   30.     public static void copyOld() {   31.         File srcFile = new File(src);   32.         File distFile = new File(dist);   33.         if (distFile.exists()) {   34.             distFile.delete();   35.         }   36.         try {   37.             FileInputStream fin = new FileInputStream(srcFile);   38.             BufferedInputStream buffIn = new BufferedInputStream(fin);   39.   40.             FileOutputStream fout = new FileOutputStream(distFile);   41.             BufferedOutputStream buffout = new BufferedOutputStream(fout);   42.             byte[] bytes = new byte[1024];   43.             while (buffIn.read(bytes) > 0) {   44.                 buffout.write(bytes);   45.             }   46.             fin.close();   47.             buffIn.close();   48.             fout.close();   49.             buffout.close();   50.         } catch (Exception e) {   51.             e.printStackTrace();   52.         }   53.   54.     }   55.   56.     public static void copyNew() {   57.         try {   58.             File srcFile = new File(src);   59.             File distFile = new File(dist);   60.             if (distFile.exists()) {   61.                 distFile.delete();   62.             }   63.   64.             FileInputStream fin = new FileInputStream(srcFile);   65.             FileOutputStream fout = new FileOutputStream(distFile);   66.             FileChannel inChannel = fin.getChannel();   67.             FileChannel outChannel = fout.getChannel();   68.             int ByteBufferSize = 1024 * 100;   69.             ByteBuffer buff = ByteBuffer.allocate(ByteBufferSize);   70.   71.             while (inChannel.read(buff) > 0) {   72.                 buff.flip();   73.                 if (inChannel.position() == inChannel.size()) {// 判断是不是最后一段数据   74.                     int lastRead = (int) (inChannel.size() % ByteBufferSize);   75.                     byte[] bytes = new byte[lastRead];   76.                     buff.get(bytes, 0, lastRead);   77.                     outChannel.write(ByteBuffer.wrap(bytes));   78.                     buff.clear();   79.                 } else {   80.                     outChannel.write(buff);   81.                     buff.clear();   82.                 }   83.             }// 这个使用FileChannel 自带的复制   84.             // outChannel.transferFrom(inChannel, 0, inChannel.size());   85.             outChannel.close();   86.             inChannel.close();   87.             fin.close();   88.             fout.close();   89.         } catch (Exception e) {   90.             e.printStackTrace();   91.         }   92.     }   93. }
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