1、工具类

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 {	/**	 * 文件拷贝，字节批量读取	 * @param srcFile	 * @param destFile	 * @throws IOException	 */	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();//最好加上	    }	    in.close();	    out.close();			}	/**	 * 进行文件的拷贝，利用带缓冲的字节流	 * @param srcFile	 * @param destFile	 * @throws IOException	 */	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();//刷新缓冲区		}		bis.close();		bos.close();	}	/**	 * 单字节，不带缓冲进行文件拷贝	 * @param srcFile	 * @param destFile	 * @throws IOException	 */	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();	}	}

2、测试结果

package com.imooc.io;import java.io.File;import java.io.IOException;public class IOUtilTest {	public static void main(String[] args) {		// TODO Auto-generated method stub		try {			long start = System.currentTimeMillis();			/*IOUtil.copyFileByByte(new File("e:\\javaio\\1.mp3"), new File(					"e:\\javaio\\2.mp3"));*/  //两万多毫秒			/*IOUtil.copyFileByBuffer(new File("e:\\javaio\\1.mp3"), new File(					"e:\\javaio\\3.mp3"));//一万多毫秒*/			IOUtil.copyFile(new File("e:\\javaio\\1.mp3"), new File(					"e:\\javaio\\4.mp3"));//7毫秒			long end = System.currentTimeMillis();			System.out.println(end - start );		} catch (IOException e) {			e.printStackTrace();		}	}}

字节读取复制：两万多毫秒

缓存字节流：一万多毫秒

字节批量读取：7毫秒