[NIO.2] 第三十七篇 编写一个文件移动应用

移动文件分为两个步骤，先拷贝文件，再删除源文件。

下面的代码将会把  C:\rafaelnadal 目录中的内容移动到 C:\ATP\players\rafaelnafal 目录中。在移动前，要确保 C:\ATP\players\rafaelnafal 目录已经存在。在这个例子中，目录的移动使用了 Files.copy() 和 Files.delete() 方法，文件的移动使用了 Files.move() 方法。

import java.io.IOException; 
import java.nio.file.FileVisitOption; 
import java.nio.file.FileVisitResult; 
import java.nio.file.FileVisitor; 
import java.nio.file.Files; 
import java.nio.file.Path; 
import java.nio.file.Paths; 
import java.nio.file.attribute.BasicFileAttributes; 
import java.nio.file.attribute.FileTime; 
import java.util.EnumSet; 
import static java.nio.file.StandardCopyOption.REPLACE_EXISTING; 
import static java.nio.file.StandardCopyOption.COPY_ATTRIBUTES; 
import static java.nio.file.StandardCopyOption.ATOMIC_MOVE; 
 
class MoveTree implements FileVisitor { 
 
   private final Path moveFrom; 
   private final Path moveTo; 
   static FileTime time = null; 
 
   public MoveTree(Path moveFrom, Path moveTo) { 
        this.moveFrom = moveFrom; 
        this.moveTo = moveTo; 
   } 
 
   static void moveSubTree(Path moveFrom, Path moveTo) throws IOException { 
        try { 
            Files.move(moveFrom, moveTo, REPLACE_EXISTING, ATOMIC_MOVE); 
        } catch (IOException e) { 
            System.err.println("Unable to move " + moveFrom + " [" + e + "]"); 
        } 
 
   } 
 
   @Override 
   public FileVisitResult postVisitDirectory(Object dir, IOException exc)  
                                                                     throws IOException { 
        Path newdir = moveTo.resolve(moveFrom.relativize((Path) dir)); 
        try { 
            Files.setLastModifiedTime(newdir, time); 
            Files.delete((Path) dir); 
        } catch (IOException e) { 
            System.err.println("Unable to copy all attributes to: " + newdir+" [" + e + "]"); 
        } 
 
        return FileVisitResult.CONTINUE; 
   } 
 
   @Override 
   public FileVisitResult preVisitDirectory(Object dir, BasicFileAttributes attrs)  
                                                                        throws IOException { 
        System.out.println("Move directory: " + (Path) dir); 
        Path newdir = moveTo.resolve(moveFrom.relativize((Path) dir)); 
        try { 
            Files.copy((Path) dir, newdir, REPLACE_EXISTING, COPY_ATTRIBUTES); 
            time = Files.getLastModifiedTime((Path) dir); 
        } catch (IOException e) { 
            System.err.println("Unable to move " + newdir + " [" + e + "]"); 
            return FileVisitResult.SKIP_SUBTREE; 
        } 
        return FileVisitResult.CONTINUE; 
   } 
   @Override 
   public FileVisitResult visitFile(Object file, BasicFileAttributes attrs)  
                                                                        throws IOException { 
        System.out.println("Move file: " + (Path) file); 
        moveSubTree((Path) file, moveTo.resolve(moveFrom.relativize((Path) file))); 
        return FileVisitResult.CONTINUE; 
   } 
   @Override 
   public FileVisitResult visitFileFailed(Object file, IOException exc)  
                                                                        throws IOException { 
        return FileVisitResult.CONTINUE; 
   } 
} 
class Main { 
    public static void main(String[] args) throws IOException { 
        Path moveFrom = Paths.get("C:/rafaelnadal"); 
        Path moveTo = Paths.get("C:/ATP/players/rafaelnadal"); 
        MoveTree walk = new MoveTree(moveFrom, moveTo); 
        EnumSet opts = EnumSet.of(FileVisitOption.FOLLOW_LINKS); 
        Files.walkFileTree(moveFrom, opts, Integer.MAX_VALUE, walk); 
    } 
}

当然，也可以不使用 Files.move() 方法，而使用 Files.copy()
和 Files.delete() 方法来移动文件：

static void moveSubTree(Path moveFrom, Path moveTo) throws IOException { 
        try { 
            Files.copy(moveFrom, moveTo, REPLACE_EXISTING, COPY_ATTRIBUTES); 
            Files.delete(moveFrom); 
        } catch (IOException e) { 
            System.err.println("Unable to move " + moveFrom + " [" + e + "]"); 
        } 
    }

文章来源：http://www.aptusource.org/2014/04/nio-2-writing-a-move-files-application/