详解Java中IO字节流基本操作（复制文件）并测试性能

 public static void main(String[] args) throws Exception {
		//源文件
		String srcFile = "src/a.mp3";
		//目的文件
		String destFile = "src/b.mp3";
		long start = System.currentTimeMillis();
        ...
		复制文件方法
        ...
		long end = System.currentTimeMillis();
		System.out.println("共耗时"+(end-start)+"毫秒");
	}

//一次读取一个字节
public static void copy1(String srcFile,String destFile) throws Exception {
		
	//封装文件
	InputStream in = new FileInputStream(srcFile);
	OutputStream out = new FileOutputStream(destFile);
		
	//复制文件
	int b = 0;
	while ((b = in.read()) != -1) {
			out.write(b);
	}
		
	//释放资源
	in.close();
	out.close();
	}

// 一次读取一个字节数组
public static void copy2(String srcFile, String destFile) throws Exception {
 
	// 封装文件
	InputStream in = new FileInputStream(srcFile);
	OutputStream out = new FileOutputStream(destFile);
 
	// 复制文件
	byte[] buff = new byte[1024];
	int len = 0;
	while ((len = in.read(buff)) != -1) {
			out.write(buff, 0, len);
	}
 
	// 释放资源
	in.close();
	out.close();
	}

/ 使用高效缓冲区一次读取一个字节
public static void copy3(String srcFile, String destFile) throws Exception {
 
	// 封装文件
	BufferedInputStream bis = new BufferedInputStream(new FileInputStream(srcFile));
	BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(destFile));
 
	// 复制文件
	int b = 0;
	while ((b = bis.read()) != -1) {
			bos.write(b);
	}
 
	// 释放资源
	bis.close();
	bos.close();
	}

// 使用高效缓冲区一次读取一个字节数组
public static void copy4(String srcFile, String destFile) throws Exception {
 
	// 封装文件
	BufferedInputStream bis = new BufferedInputStream(new FileInputStream(srcFile));
	BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(destFile));
 
	// 复制文件
	byte[] buf = new byte[1024];
	int len = 0;
	while ((len = bis.read(buf)) != -1) {
			bos.write(buf, 0, len);
	}
 
	// 释放资源
	bis.close();
	bos.close();
	}