JAVA复制文件最快的算法

/**
* 复制文件
*
* @param srcFile
* 源文件File
* @param destDir
* 目标目录File
* @param newFileName
* 新文件名
* @return 实际复制的字节数，如果文件、目录不存在、文件为null或者发生IO异常，返回-1
*/
public static long copyFile1(File srcFile, File destDir, String newFileName) {
long copySizes = 0;
if (!srcFile.exists()) {
System.out.println("源文件不存在");
copySizes = -1;
} else if (!destDir.exists()) {
System.out.println("目标目录不存在");
copySizes = -1;
} else if (newFileName == null) {
System.out.println("文件名为null");
copySizes = -1;
} else {
try {
BufferedInputStream bin = new BufferedInputStream(
new FileInputStream(srcFile));
BufferedOutputStream bout = new BufferedOutputStream(
new FileOutputStream(new File(destDir, newFileName)));
int b = 0, i = 0;
while ((b = bin.read()) != -1) {
bout.write(b);
i++;
}
bout.flush();
bin.close();
bout.close();
copySizes = i;

} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
return copySizes;
}

/**
* 复制文件(以超快的速度复制文件)
*
* @param srcFile
* 源文件File
* @param destDir
* 目标目录File
* @param newFileName
* 新文件名
* @return 实际复制的字节数，如果文件、目录不存在、文件为null或者发生IO异常，返回-1
*/
public static long copyFile2(File srcFile, File destDir, String newFileName) {
long copySizes = 0;
if (!srcFile.exists()) {
System.out.println("源文件不存在");
copySizes = -1;
} else if (!destDir.exists()) {
System.out.println("目标目录不存在");
copySizes = -1;
} else if (newFileName == null) {
System.out.println("文件名为null");
copySizes = -1;
} else {
try {
FileChannel fcin = new FileInputStream(srcFile).getChannel();
FileChannel fcout = new FileOutputStream(new File(destDir,
newFileName)).getChannel();
long size = fcin.size();
fcin.transferTo(0, fcin.size(), fcout);
fcin.close();
fcout.close();
copySizes = size;
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
return copySizes;
}

JAVA复制文件最快的算法,布布扣,bubuko.com

JAVA复制文件最快的算法

原文：http://www.cnblogs.com/azhqiang/p/3922032.html