文件上传：

代码1：

InputStream is = mFile.getInputStream();//mFile为MultipartFile实例
File destFile = new File(savePath, newName);
OutputStream os = new FileOutputStream(destFile);
byte[] buffer = new byte[400];
int length = 0;
while ((length = is.read(buffer)) > 0) {
os.write(buffer, 0, length);
}
is.close();
os.close();

代码2：

InputStream is = mFile.getInputStream();//mFile为MultipartFile实例
File destFile = new File(savePath, newName);
OutputStream os = new FileOutputStream(destFile);
byte[] buffer = new byte[400];
int length = 0;
BufferedInputStream bis = new BufferedInputStream(is);//添加缓存
BufferedOutputStream bos = new BufferedOutputStream(os);
while ((length = bis.read(buffer)) > 0) {
bos.write(buffer, 0, length);
}
is.close();
os.close();

第一种写法也是一块一块的读入、输出的，我以为就相当于是进行了缓冲；采用第二种写法速度明显提高，哪位大神可以解释一下两种方法的运行原理，在此谢过！