java io 流 效率

作者：roger51

http://roger51.javaeye.com/blog/105498

import java.io.*;public class IOTest {public static void main(String[] args){             IOTest io = new IOTest();             try{             long startTime = System.currentTimeMillis();             io.readWrite("c:/temp/1.txt","c:/temp/2.txt");                  long endTime = System.currentTimeMillis();             System.out.println("Time taken for reading and writing using default behaviour : "                                                           + (endTime - startTime) + " milli seconds" );              long startTime1 = System.currentTimeMillis();             io.readWriteBuffer("c:/temp/1.txt","c:/temp/2.txt");                         long endTime1 = System.currentTimeMillis();             System.out.println("Time taken for reading and writing using buffered streams : "                                                           + (endTime1 - startTime1) + " milli seconds" );              long startTime2 = System.currentTimeMillis();             io.readWriteArray("c:/temp/1.txt","c:/temp/2.txt");                           long endTime2 = System.currentTimeMillis();             System.out.println("Time taken for reading and writing using custom buffering : "                                                           + (endTime2 - startTime2) + " milli seconds" );             }catch(IOException e){ e.printStackTrace();}}public static void readWrite(String fileFrom, String fileTo) throws IOException{             InputStream in = null;             OutputStream out = null;             try{                          in = new FileInputStream(fileFrom);                          out = new FileOutputStream(fileTo);                          while(true){                                          int bytedata = in.read();                                          if(bytedata == -1)                                          break;                                          out.write(bytedata);                          }             }             finally{              if(in != null)                          in.close();              if(out !=null)                          out.close();             }}public static void readWriteBuffer(String fileFrom, String fileTo) throws IOException{             InputStream inBuffer = null;             OutputStream outBuffer = null;             try{                          InputStream in = new FileInputStream(fileFrom);                          inBuffer = new BufferedInputStream(in);                          OutputStream out = new FileOutputStream(fileTo);                          outBuffer = new BufferedOutputStream(out);                          while(true){                                          int bytedata = inBuffer.read();                                          if(bytedata == -1)                                          break;                                          out.write(bytedata);                          }             }             finally{              if(inBuffer != null)                          inBuffer.close();              if(outBuffer !=null)                          outBuffer.close();             }}           public static void readWriteArray(String fileFrom, String fileTo) throws IOException{             InputStream in = null;             OutputStream out = null;             try{                          in = new FileInputStream(fileFrom);                          out = new FileOutputStream(fileTo);                          int availableLength = in.available();                          byte[] totalBytes = new byte[availableLength];                          int bytedata = in.read(totalBytes);                          out.write(totalBytes);                                          }             finally{              if(in != null)                          in.close();              if(out !=null)                          out.close();             }}           }