Java 7如何操纵文件属性

               

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

           

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