[NIO] Stream 파일복사 vs Buffer/Channel 파일복사

기존 Stream을 이용한 파일 Copy

import java.io.FileInputStream; import java.io.FileOutputStream; import java.nio.ByteBuffer; import java.nio.channels.FileChannel;   public class CopyChannels {        public static void main(String[] args) throws Exception {                             String fromFileName = args[0];               String toFileName = args[1];                             FileChannel in = new FileInputStream(fromFileName).getChannel();               FileChannel out = new FileOutputStream(toFileName).getChannel();                 ByteBuffer buff = ByteBuffer.allocate(32 * 1024);                 while (in.read(buff) > 0) {                      buff.flip();                      out.write(buff);                      buff.clear();               }                 in.close();               out.close();        } }

Buffer, Channel을 이용한 파일 Copy

 Eg. 1 

import java.io.FileInputStream; import java.io.FileOutputStream; import java.nio.ByteBuffer; import java.nio.channels.FileChannel;   public class CopyChannels {        public static void main(String[] args) throws Exception {                             String fromFileName = args[0];               String toFileName = args[1];                             FileChannel in = new FileInputStream(fromFileName).getChannel();               FileChannel out = new FileOutputStream(toFileName).getChannel();                 ByteBuffer buff = ByteBuffer.allocate(32 * 1024);                 while (in.read(buff) > 0) {                      buff.flip();                      out.write(buff);                      buff.clear();               }                 in.close();               out.close();        } }

 

 Eg. 2 

import java.io.FileInputStream; import java.io.FileOutputStream; import java.nio.ByteBuffer; import java.nio.channels.FileChannel;   public class CopyChannels2 {        public static void main(String[] args) throws Exception {                             String fromFileName = args[0];               String toFileName = args[1];                             FileChannel in = new FileInputStream(fromFileName).getChannel();               FileChannel out = new FileOutputStream(toFileName).getChannel();                 ByteBuffer buff = ByteBuffer.allocateDirect(32 * 1024);                 while (in.read(buff) > 0) {                      buff.flip();                      out.write(buff);                      buff.clear();               }                 in.close();               out.close();        } }

 

 Eg. 3 

import java.io.FileInputStream; import java.io.FileOutputStream; import java.nio.channels.FileChannel;   public class CopyChannels3 {        public static void main(String[] args) throws Exception {                             String fromFileName = args[0];               String toFileName = args[1];                 FileChannel in = new FileInputStream(fromFileName).getChannel();               FileChannel out = new FileOutputStream(toFileName).getChannel();                 in.transferTo(0, (int) in.size(), out);                 in.close();               out.close();        } }