使用流
private static void copyFileUsingStream(File source, File dest) throws IOException {
InputStream is = null;
OutputStream os = null;
try {
is = new FileInputStream(source);
os = new FileOutputStream(dest);
byte[] buffer = new byte[1024];
int length;
while ((length = is.read(buffer)) > 0) {
os.write(buffer, 0, length);
}
} finally {
is.close();
os.close();
}
}
使用频道
private static void copyFileUsingChannel(File source, File dest) throws IOException {
FileChannel sourceChannel = null;
FileChannel destChannel = null;
try {
sourceChannel = new FileInputStream(source).getChannel();
destChannel = new FileOutputStream(dest).getChannel();
destChannel.transferFrom(sourceChannel, 0, sourceChannel.size());
}finally{
sourceChannel.close();
destChannel.close();
}
}
使用 Apache Commons IO 库：
private static void copyFileUsingApacheCommonsIO(File source, File dest) throws IOException {
FileUtils.copyFile(source, dest);
}
使用 Java SE 7 Files 类：
private static void copyFileUsingJava7Files(File source, File dest) throws IOException {
Files.copy(source.toPath(), dest.toPath());
}
或者试试 Googles Guava：
https://github.com/google/guava
文档：
https://guava.dev/releases/snapshot-jre/api/docs/com/google/common/io/Files.html
比较时间：
File source = new File("/Users/sidikov/tmp/source.avi");
File dest = new File("/Users/sidikov/tmp/dest.avi");
//copy file conventional way using Stream
long start = System.nanoTime();
copyFileUsingStream(source, dest);
System.out.println("Time taken by Stream Copy = "+(System.nanoTime()-start));
//copy files using java.nio FileChannel
source = new File("/Users/sidikov/tmp/sourceChannel.avi");
dest = new File("/Users/sidikov/tmp/destChannel.avi");
start = System.nanoTime();
copyFileUsingChannel(source, dest);
System.out.println("Time taken by Channel Copy = "+(System.nanoTime()-start));
//copy files using apache commons io
source = new File("/Users/sidikov/tmp/sourceApache.avi");
dest = new File("/Users/sidikov/tmp/destApache.avi");
start = System.nanoTime();
copyFileUsingApacheCommonsIO(source, dest);
System.out.println("Time taken by Apache Commons IO Copy = "+(System.nanoTime()-start));
//using Java 7 Files class
source = new File("/Users/sidikov/tmp/sourceJava7.avi");
dest = new File("/Users/sidikov/tmp/destJava7.avi");
start = System.nanoTime();
copyFileUsingJava7Files(source, dest);
System.out.println("Time taken by Java7 Files Copy = "+(System.nanoTime()-start));