Java文件拷贝的几种实现方案

在jdk1.7之前，java中没有直接的类提供文件复制功能。下面就文件复制，提出几种方案。

jdk1.7中的文件复制

在jdk1.7版本中可以直接使用Files.copy(File srcFile, File destFile)方法即可。

private static void copyFileUsingJava7Files(File source, File dest)
throws IOException {
Files.copy(source.toPath(), dest.toPath());
}

使用FileInputStream复制

/**
*
* @Title: copyFileUsingStream
* @Description: 使用Stream拷贝文件
* @param: @param source
* @param: @param dest
* @param: @throws IOException
* @return: void
* @throws
*/
public 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 {
if(is != null) {
is.close();
}
if(os != null) {
os.close();
}
}
}

使用FileChannel实现复制

/**
* @throws IOException
*
* @Title: copyFileUsingChannel
* @Description: 使用Channel拷贝文件
* @param: @param source
* @param: @param dest
* @return: void
* @throws
*/
public 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 {
if(sourceChannel != null) {
sourceChannel.close();
}
if(destChannel != null) {
destChannel.close();
}
}
}

使用Apache Commons IO包中的FileUtils.copyFile复制

public static void copyFileUsingApacheIO(File source, File dest) throws IOException {
FileUtils.copyFile(source, dest);
}

使用IO重定向实现复制

/**
*
* @Title: copyFileUsingRedirection
* @Description: 使用Redirection拷贝文件
* @param: @param source
* @param: @param dest
* @param: @throws IOException
* @return: void
* @throws
*/
public static void copyFileUsingRedirection(File source, File dest) throws IOException {
FileInputStream in = null;
PrintStream out = null;
try {
in = new FileInputStream(source);
out = new PrintStream(dest);
System.setIn(in);
System.setOut(out);
Scanner sc = new Scanner(System.in);
while(sc.hasNext()) {
System.out.println(sc.nextLine());
}
} finally{
if(in != null) {
in.close();
}
if(out != null) {
out.close();
}
}
}