java文件拷贝方式在100MB文件条件下速度的比较

package com.imooc.io;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class IOUtil {
    public static void copyFile(File srcFile,File destFile)throws IOException{
        if(!srcFile.exists()){
            throw new IllegalArgumentException("文件:"+srcFile+"不存在");
        }
        if(!srcFile.isFile()){
            throw new IllegalArgumentException(srcFile+"不是文件");
        }
        FileInputStream in = new FileInputStream(srcFile);
        FileOutputStream out = new FileOutputStream(destFile);
        byte[] buf = new byte[8*1024];
        int b ;
        while((b = in.read(buf,0,buf.length))!=-1){
            out.write(buf,0,b);
            out.flush();
        }
        in.close();
        out.close();

    }

    public static void copyFileByBuffer(File srcFile,File destFile)throws IOException{
        if(!srcFile.exists()){
            throw new IllegalArgumentException("文件:"+srcFile+"不存在");
        }
        if(!srcFile.isFile()){
            throw new IllegalArgumentException(srcFile+"不是文件");
        }
        BufferedInputStream bis = new BufferedInputStream(
                new FileInputStream(srcFile));
        BufferedOutputStream bos = new BufferedOutputStream(
                new FileOutputStream(destFile));
        int c ;
        while((c = bis.read())!=-1){
            bos.write(c);
            bos.flush();
        }
        bis.close();
        bos.close();
    }

    public static void copyFileByBuffer2(File srcFile,File destFile)throws IOException{
        if(!srcFile.exists()){
            throw new IllegalArgumentException("文件:"+srcFile+"不存在");
        }
        if(!srcFile.isFile()){
            throw new IllegalArgumentException(srcFile+"不是文件");
        }
        BufferedInputStream bis = new BufferedInputStream(
                new FileInputStream(srcFile));
        BufferedOutputStream bos = new BufferedOutputStream(
                new FileOutputStream(destFile));
        byte[] buf = new byte[8*1024];
        int b ;
        while((b = bis.read(buf,0,buf.length))!=-1){
            bos.write(buf,0,b);
            bos.flush();
        }
        bis.close();
        bos.close();
    }
    public static void copyFileByByte(File srcFile,File destFile)throws IOException{
        if(!srcFile.exists()){
            throw new IllegalArgumentException("文件:"+srcFile+"不存在");
        }
        if(!srcFile.isFile()){
            throw new IllegalArgumentException(srcFile+"不是文件");
        }
        FileInputStream in = new FileInputStream(srcFile);
        FileOutputStream out = new FileOutputStream(destFile);
        int c ;
        while((c = in.read())!=-1){
            out.write(c);
            out.flush();
        }
        in.close();
        out.close();
    }

}

package com.imooc.io;

import java.io.File;
import java.io.IOException;

public class IOUtilTest4 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        try {
            File f=new File("e:\\guanjujinqinpp.apk");
            //按字节批量读取方式拷贝文件时间测试100MB以上
            long start = System.currentTimeMillis();
            IOUtil.copyFile(f, new File(
                    "e:\\test1.apk"));
            long end = System.currentTimeMillis();
            System.out.println("文件大小"+f.length()/1024/1024+"MB\t"+"字节批量读取方式拷贝文件所需时间"+(end - start)+"ms" );  
            //按批量缓冲方式读取文件拷贝文件时间测试100MB以上
            start = System.currentTimeMillis();
            IOUtil.copyFileByBuffer2(f, new File(
                    "e:\\test2.apk"));
            end = System.currentTimeMillis();
            System.out.println("文件大小"+f.length()/1024/1024+"MB\t"+"缓冲批量读取方式拷贝文件所需时间"+(end - start)+"ms" );

            //按缓冲方式读取方式拷贝文件测试100MB以上
            start = System.currentTimeMillis();
            IOUtil.copyFileByBuffer(f, new File(
                    "e:\\test3.apk"));
            end = System.currentTimeMillis();
            System.out.println("文件大小"+f.length()/1024/1024+"MB\t"+"缓冲读取方式拷贝文件所需时间"+(end - start) +"ms");    

            //按字节读取方式拷贝文件测试100MB以上
            start = System.currentTimeMillis();
            IOUtil.copyFileByByte(f, new File(
                    "e:\\test4.apk"));
            end = System.currentTimeMillis();
            System.out.println("文件大小"+f.length()/1024/1024+"MB\t"+"字节读取方式拷贝文件所需时间"+(end - start)+"ms" );
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

通过比较，可以看出批量拷贝的优势，但是在100MB左右的文件拷贝条件下，批量缓冲比批量字节并没有太大的优势。