Java 7如何操纵文件属性

作者：chszs，转载需注明。博客主页：http://blog.csdn.net/chszs

准备写点基础性的文章，Java 7已经出来很长一段时间了，但是很多Java程序员仍然停留在早期的Java 5或Java 6的基础上，对Java 7的新特性从未加以使用。本文介绍如何利用Java 7的NIO包读取文件属性以及修改文件属性。详情如下：

1、读取文件属性

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.nio.file.attribute.BasicFileAttributes;

import java.util.logging.Level;

import java.util.logging.Logger;

public class ReadFileAttribute1 {

	public static void main(String[] args){

		Path filePath = Paths.get("d:\\test.txt");

		try{

			BasicFileAttributes ra = Files.readAttributes(filePath, BasicFileAttributes.class);

			System.out.println("CREATION TIME:" + ra.creationTime());

			System.out.println("LAST ACCESS TIME:" + ra.lastAccessTime());

			System.out.println("FILE SIZE:" + ra.size());

			System.out.println("LAST MODIFIED:" + ra.lastModifiedTime());

			System.out.println("IS SYSBOLIC LINK:" + ra.isSymbolicLink());

			System.out.println("IS FOLDER:" + ra.isDirectory());

			System.out.println("IS FILE:" + ra.isRegularFile());

		}catch(IOException e){

			Logger.getLogger(ReadFileAttribute1.class.getName()).log(Level.SEVERE, null, e);

		}

	}

}

输出：
CREATION TIME:2013-04-09T05:45:30.685152Z

LAST ACCESS TIME:2013-08-12T00:30:43.19369Z

FILE SIZE:32

LAST MODIFIED:2013-12-10T13:35:08.438828Z

IS SYSBOLIC LINK:false

IS FOLDER:false

IS FILE:true

2、另一种读取文件属性的方法

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.logging.Level;

import java.util.logging.Logger;

public class ReadFileAttribute2 {

	public static void main(String[] args){

		Path fp = Paths.get("D:\\test.txt");

		try{

			Files.getAttribute(fp, "basic:size");

			System.out.println("CREATION TIME:" + Files.getAttribute(fp, "basic:creationTime").toString());

			System.out.println("LAST ACCESS TIME:" + Files.getAttribute(fp, "basic:lastAccessTime").toString());

			System.out.println("FILE SIZE:" + Files.getAttribute(fp, "basic:size").toString());

			System.out.println("LAST MODIFIED:" + Files.getAttribute(fp, "basic:lastModifiedTime").toString());

			System.out.println("IS SYSBOLIC LINK:" + Files.getAttribute(fp, "basic:isSymbolicLink").toString());

			System.out.println("IS FOLDER:" + Files.getAttribute(fp, "basic:isDirectory").toString());

			System.out.println("IS FILE:" + Files.getAttribute(fp, "basic:isRegularFile").toString());

		}catch(IOException e){

			Logger.getLogger(ReadFileAttribute2.class.getName()).log(Level.SEVERE, null, e);

		}

	}

}

输出：

CREATION TIME:2013-04-09T05:45:30.685152Z

LAST ACCESS TIME:2013-08-12T00:30:43.19369Z

FILE SIZE:32

LAST MODIFIED:2013-12-10T13:35:08.438828Z

IS SYSBOLIC LINK:false

IS FOLDER:false

IS FILE:true

3、修改文件属性

import java.io.IOException;

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.logging.Level;

import java.util.logging.Logger;

public class UpdateFileAttribute1 {

	public static void main(String[] args){

		Path fp = Paths.get("D:\\test.txt");

		try{

			BasicFileAttributes ra = Files.readAttributes(fp, BasicFileAttributes.class);

			long currentTimeMillis = System.currentTimeMillis();

			FileTime fileTime = FileTime.fromMillis(currentTimeMillis);

			Files.setAttribute(fp, "basic:creationTime", fileTime);

			FileTime creationTime = (FileTime)Files.getAttribute(fp, "basic:creationTime");

			System.out.println("NEW CREATION TIME:" + creationTime.toString());

			System.out.println("OLD CREATION TIME:" + ra.creationTime());

		}catch(IOException e){

			Logger.getLogger(UpdateFileAttribute1.class.getName()).log(Level.SEVERE, null, e);

		}

	}

}

输出：

NEW CREATION TIME:2013-12-10T15:04:26.159Z
OLD CREATION TIME:2013-04-09T05:45:30.685152Z

4、还可以修改文件别的属性

import java.io.IOException;

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.logging.Level;

import java.util.logging.Logger;

public class UpdateFileAttribute2 {

	public static void main(String[] args){

		Path fp = Paths.get("D:\\test.txt");

		try{

			BasicFileAttributes ra = Files.readAttributes(fp, BasicFileAttributes.class);

			long currentTimeMillis = System.currentTimeMillis();

			FileTime fileTime = FileTime.fromMillis(currentTimeMillis);

			Files.setAttribute(fp, "basic:lastAccessTime", fileTime);

			FileTime creationTime = (FileTime)Files.getAttribute(fp, "basic:lastAccessTime");

			System.out.println("NEW LAST-ACCESS-TIME:" + creationTime.toString());

			System.out.println("OLD LAST-ACCESS-TIME:" + ra.lastAccessTime());

		}catch(IOException e){

			Logger.getLogger(UpdateFileAttribute2.class.getName()).log(Level.SEVERE, null, e);

		}

	}

}

输出：

NEW LAST-ACCESS-TIME:2013-12-10T15:07:46.261Z
OLD LAST-ACCESS-TIME:2013-08-12T00:30:43.19369Z

5、另一种修改文件属性的方法

import java.io.IOException;

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.logging.Level;

import java.util.logging.Logger;

public class UpdateFileAttribute3 {

	public static void main(String[] args){

		Path fp = Paths.get("D:\\test.txt");

		try{

			BasicFileAttributes ra = Files.readAttributes(fp, BasicFileAttributes.class);

			long currentTimeMillis = System.currentTimeMillis();

			FileTime fileTime = FileTime.fromMillis(currentTimeMillis);

			Files.setLastModifiedTime(fp, fileTime);

			FileTime time = (FileTime)Files.getAttribute(fp, "basic:lastModifiedTime");

			System.out.println("NEW LAST-MODIFIED-TIME:" + time.toString());

			System.out.println("OLD LAST-MODIFIED-TIME:" + ra.lastModifiedTime());

		}catch(IOException e){

			Logger.getLogger(UpdateFileAttribute3.class.getName()).log(Level.SEVERE, null, e);

		}

	}

}

输出：
NEW LAST-MODIFIED-TIME:2013-12-10T15:13:07.134Z

OLD LAST-MODIFIED-TIME:2013-12-10T13:35:08.438828Z