![](https://img.laitimes.com/img/_0nNw4CM6IyYiwiM6ICdiwiI0gTMx81dsQWZ4lmZf1GLlpXazVmcvwFciV2dsQXYtJ3bm9CX9s2RkBnVHFmb1clWvB3MaVnRtp1XlBXe0xCMy81dvRWYoNHLwEzX5xCMx8FesU2cfdGLwMzX0xiRGZkRGZ0Xy9GbvNGLpZTY1EmMZVDUSFTU4VFRR9Fd4VGdsYTMfVmepNHLrJXYtJXZ0F2dvwVZnFWbp1zczV2YvJHctM3cv1Ce-cmbw5SO2gTNzgzMwcTN1MjN1UjNzYzX5AzMxIDM1AzLcFTMyIDMy8CXn9Gbi9CXzV2Zh1WavwVbvNmLvR3YxUjLyM3Lc9CX6MHc0RHaiojIsJye.png)
典型回答
Java 有多种比较典型的文件拷贝实现方式,比如:
利用 java.io 类库,直接为源文件构建一个 FileInputStream 读取,然后再为目标文件构建一个 FileOutputStream,完成写入工作。
public static void copyFileByStream(File source, File dest) throws
IOException {
try (InputStream is = new FileInputStream(source);
OutputStream os = new FileOutputStream(dest);){
byte[] buffer = new byte[1024];
int length;
while ((length = is.read(buffer)) > 0) {
os.write(buffer, 0, length);
}
}
}
或者,利用 java.nio 类库提供的 transferTo 或 transferFrom 方法实现。
public static void copyFileByChannel(File source, File dest) throws
IOException {
try (FileChannel sourceChannel = new FileInputStream(source)
.getChannel();
FileChannel targetChannel = new FileOutputStream(dest).getChannel
();){
for (long count = sourceChannel.size() ;count>0 ;) {
long transferred = sourceChannel.transferTo(
sourceChannel.position(), count, targetChannel); sourceChannel.position(sourceChannel.position() + transferred);
count -= transferred;
}
}
}
当然,Java 标准类库本身已经提供了几种 Files.copy 的实现。