关于java：如何将文件从一个位置复制到另一个位置？

How to copy file from one location to another location?

我想把文件从一个位置复制到Java中的另一个位置。最好的方法是什么？

以下是迄今为止我所拥有的：

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import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.List;
public class TestArrayList {
public static void main(String[] args) {
File f = new File(
"D:\\CBSE_Demo\\Demo_original\\fscommand\\contentplayer\\config");
List<String>temp=new ArrayList<String>();
temp.add(0,"N33");
temp.add(1,"N1417");
temp.add(2,"N331");
File[] matchingFiles = null;
for(final String temp1: temp){
matchingFiles = f.listFiles(new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.startsWith(temp1);
}
});
System.out.println("size>>--"+matchingFiles.length);

}
}
}

这不会复制文件，最好的方法是什么？

相关讨论

您可以使用这个(或任何变体)：

1	Files.copy(src, dst, StandardCopyOption.REPLACE_EXISTING);

另外，我建议使用File.separator或/，而不是\\，以使它在多个操作系统中兼容，这里提供关于这个的问题/答案。

由于您不确定如何临时存储文件，请查看ArrayList：

1 2	List<File> files = new ArrayList(); files.add(foundFile);

要将文件的List移动到单个目录中，请执行以下操作：

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List<File> files = ...;
String path ="C:/destination/";
for(File file : files) {
Files.copy(file.toPath(),
(new File(path + file.getName())).toPath(),
StandardCopyOption.REPLACE_EXISTING);
}

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使用流

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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();
}
}

使用信道

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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-Lib：

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

使用Java SE 7文件类：

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

性能测试：

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File source = new File("/Users/pankaj/tmp/source.avi");
File dest = new File("/Users/pankaj/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/pankaj/tmp/sourceChannel.avi");
dest = new File("/Users/pankaj/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/pankaj/tmp/sourceApache.avi");
dest = new File("/Users/pankaj/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/pankaj/tmp/sourceJava7.avi");
dest = new File("/Users/pankaj/tmp/destJava7.avi");
start = System.nanoTime();
copyFileUsingJava7Files(source, dest);
System.out.println("Time taken by Java7 Files Copy ="+(System.nanoTime()-start));

结果：

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/*
* File copy:
* Time taken by Stream Copy = 44582575000
* Time taken by Channel Copy = 104138195000
* Time taken by Apache Commons IO Copy = 108396714000
* Time taken by Java7 Files Copy = 89061578000
*/

链接：

相关讨论

在Java>＝7中使用新的Java文件类。

创建以下方法并导入必要的libs。

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public static void copyFile( File from, File to ) throws IOException {
Files.copy( from.toPath(), to.toPath() );
}

在main中使用如下创建的方法：

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File dirFrom = new File(fileFrom);
File dirTo = new File(fileTo);

try {
copyFile(dirFrom, dirTo);
} catch (IOException ex) {
Logger.getLogger(TestJava8.class.getName()).log(Level.SEVERE, null, ex);
}

注意：fileFrom是要复制到其他文件夹中新文件fileTo的文件。

信用：@史葛：在Java中复制文件的标准简明方式？

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public static void copyFile(File oldLocation, File newLocation) throws IOException {
if ( oldLocation.exists( )) {
BufferedInputStream reader = new BufferedInputStream( new FileInputStream(oldLocation) );
BufferedOutputStream writer = new BufferedOutputStream( new FileOutputStream(newLocation, false));
try {
byte[] buff = new byte[8192];
int numChars;
while ( (numChars = reader.read( buff, 0, buff.length ) ) != -1) {
writer.write( buff, 0, numChars );
}
} catch( IOException ex ) {
throw new IOException("IOException when transferring" + oldLocation.getPath() +" to" + newLocation.getPath());
} finally {
try {
if ( reader != null ){
writer.close();
reader.close();
}
} catch( IOException ex ){
Log.e(TAG,"Error closing files when transferring" + oldLocation.getPath() +" to" + newLocation.getPath() );
}
}
} else {
throw new IOException("Old location does not exist when transferring" + oldLocation.getPath() +" to" + newLocation.getPath() );
}
}

文件(存在)

文件.创建目录()

文件，拷贝()

覆盖现有文件：文件.MOVER()

文件，删除()

文件.walkfiletree()在此处输入链接说明

将文件从一个位置复制到另一个位置意味着，需要将整个内容复制到另一个位置。Files.copy(Path source, Path target, CopyOption... options) throws IOException此方法要求源位置为原始文件位置，目标位置为目标文件类型相同(与原始文件相同)的新文件夹位置。目标位置需要存在于我们的系统中，否则我们需要创建一个文件夹位置，然后在该文件夹位置，我们需要创建一个与原始文件名同名的文件。然后使用复制功能，我们可以轻松地将文件从一个位置复制到另一个位置。

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public static void main(String[] args) throws IOException {
String destFolderPath ="D:/TestFile/abc";
String fileName ="pqr.xlsx";
String sourceFilePath="D:/TestFile/xyz.xlsx";
File f = new File(destFolderPath);
if(f.mkdir()){
System.out.println("Directory created!!!!");
}
else {
System.out.println("Directory Exists!!!!");
}
f= new File(destFolderPath,fileName);
if(f.createNewFile()) {

System.out.println("File Created!!!!");
} else {
System.out.println("File exists!!!!");
}

Files.copy(Paths.get(sourceFilePath), Paths.get(destFolderPath, fileName),REPLACE_EXISTING);
System.out.println("Copy done!!!!!!!!!!!!!!");

}

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