如何使用Java发现文件的创建时间？

Question

有没有一种简单的方法可以用Java发现文件的创建时间？ File类只有一个获取“上次修改”时间的方法。根据我在Google上找到的一些资源，File类不提供getCreationTime（）方法，因为并非所有文件系统都支持创建时的想法。

唯一可行的解​​决方案是我发现involes会弹出命令行并执行“dir”命令，看起来它会输出文件的创建时间。我想这很有用，我只需要支持Windows，但这对我来说似乎很容易出错。

是否有任何第三方图书馆提供我需要的信息？

更新最后，我认为购买第三方库并不值得我购买第三方库，但他们的API看起来确实不错，所以对于其他人来说这可能是一个不错的选择。有这个问题。

Answer 1

随着Java 7的发布，有一种内置的方法可以做到这一点：

Path path = Paths.get("path/to/file");
BasicFileAttributes attributes = Files.readAttributes(path, BasicFileAttributes.class);
FileTime creationTime = attributes.creationTime();

请务必注意，并非所有操作系统都提供此信息。我相信在这些情况下，它会返回mtime，这是最后修改的时间。

Windows确实提供了创建时间。

Answer 2

我几天前写过一个小型测试课，希望它可以帮到你：

// Get/Set windows file CreationTime/LastWriteTime/LastAccessTime
// Test with jna-3.2.7
// [http://maclife.net/wiki/index.php?title=Java_get_and_set_windows_system_file_creation_time_via_JNA_(Java_Native_Access)][1]

import java.io.*;
import java.nio.*;
import java.util.Date;

// Java Native Access library: jna.dev.java.net
import com.sun.jna.*;
import com.sun.jna.ptr.*;
import com.sun.jna.win32.*;
import com.sun.jna.platform.win32.*;

public class WindowsFileTime
{
    public static final int GENERIC_READ = 0x80000000;
    //public static final int GENERIC_WRITE = 0x40000000;   // defined in com.sun.jna.platform.win32.WinNT
    public static final int GENERIC_EXECUTE = 0x20000000;
    public static final int GENERIC_ALL = 0x10000000;

    // defined in com.sun.jna.platform.win32.WinNT
    //public static final int CREATE_NEW = 1;
    //public static final int CREATE_ALWAYS = 2;
    //public static final int OPEN_EXISTING = 3;
    //public static final int OPEN_ALWAYS = 4;
    //public static final int TRUNCATE_EXISTING = 5;

    public interface MoreKernel32 extends Kernel32
    {
        static final MoreKernel32 instance = (MoreKernel32)Native.loadLibrary ("kernel32", MoreKernel32.class, W32APIOptions.DEFAULT_OPTIONS);
        boolean GetFileTime (WinNT.HANDLE hFile, WinBase.FILETIME lpCreationTime, WinBase.FILETIME lpLastAccessTime, WinBase.FILETIME lpLastWriteTime);
        boolean SetFileTime (WinNT.HANDLE hFile, final WinBase.FILETIME lpCreationTime, final WinBase.FILETIME lpLastAccessTime, final WinBase.FILETIME lpLastWriteTime);
    }

    static MoreKernel32 win32 = MoreKernel32.instance;
    //static Kernel32 _win32 = (Kernel32)win32;

    static WinBase.FILETIME _creationTime = new WinBase.FILETIME ();
    static WinBase.FILETIME _lastWriteTime = new WinBase.FILETIME ();
    static WinBase.FILETIME _lastAccessTime = new WinBase.FILETIME ();

    static boolean GetFileTime (String sFileName, Date creationTime, Date lastWriteTime, Date lastAccessTime)
    {
        WinNT.HANDLE hFile = OpenFile (sFileName, GENERIC_READ);    // may be WinNT.GENERIC_READ in future jna version.
        if (hFile == WinBase.INVALID_HANDLE_VALUE) return false;

        boolean rc = win32.GetFileTime (hFile, _creationTime, _lastAccessTime, _lastWriteTime);
        if (rc)
        {
            if (creationTime != null) creationTime.setTime (_creationTime.toLong());
            if (lastAccessTime != null) lastAccessTime.setTime (_lastAccessTime.toLong());
            if (lastWriteTime != null) lastWriteTime.setTime (_lastWriteTime.toLong());
        }
        else
        {
            int iLastError = win32.GetLastError();
            System.out.print ("获取文件时间失败，错误码：" + iLastError + " " + GetWindowsSystemErrorMessage (iLastError));
        }
        win32.CloseHandle (hFile);
        return rc;
    }
    static boolean SetFileTime (String sFileName, final Date creationTime, final Date lastWriteTime, final Date lastAccessTime)
    {
        WinNT.HANDLE hFile = OpenFile (sFileName, WinNT.GENERIC_WRITE);
        if (hFile == WinBase.INVALID_HANDLE_VALUE) return false;

        ConvertDateToFILETIME (creationTime, _creationTime);
        ConvertDateToFILETIME (lastWriteTime, _lastWriteTime);
        ConvertDateToFILETIME (lastAccessTime, _lastAccessTime);

        //System.out.println ("creationTime: " + creationTime);
        //System.out.println ("lastWriteTime: " + lastWriteTime);
        //System.out.println ("lastAccessTime: " + lastAccessTime);

        //System.out.println ("_creationTime: " + _creationTime);
        //System.out.println ("_lastWriteTime: " + _lastWriteTime);
        //System.out.println ("_lastAccessTime: " + _lastAccessTime);

        boolean rc = win32.SetFileTime (hFile, creationTime==null?null:_creationTime, lastAccessTime==null?null:_lastAccessTime, lastWriteTime==null?null:_lastWriteTime);
        if (! rc)
        {
            int iLastError = win32.GetLastError();
            System.out.print ("设置文件时间失败，错误码：" + iLastError + " " + GetWindowsSystemErrorMessage (iLastError));
        }
        win32.CloseHandle (hFile);
        return rc;
    }
    static void ConvertDateToFILETIME (Date date, WinBase.FILETIME ft)
    {
        if (ft != null)
        {
            long iFileTime = 0;
            if (date != null)
            {
                iFileTime = WinBase.FILETIME.dateToFileTime (date);
                ft.dwHighDateTime = (int)((iFileTime >> 32) & 0xFFFFFFFFL);
                ft.dwLowDateTime = (int)(iFileTime & 0xFFFFFFFFL);
            }
            else
            {
                ft.dwHighDateTime = 0;
                ft.dwLowDateTime = 0;
            }
        }
    }

    static WinNT.HANDLE OpenFile (String sFileName, int dwDesiredAccess)
    {
        WinNT.HANDLE hFile = win32.CreateFile (
            sFileName,
            dwDesiredAccess,
            0,
            null,
            WinNT.OPEN_EXISTING,
            0,
            null
            );
        if (hFile == WinBase.INVALID_HANDLE_VALUE)
        {
            int iLastError = win32.GetLastError();
            System.out.print (" 打开文件失败，错误码：" + iLastError + " " + GetWindowsSystemErrorMessage (iLastError));
        }
        return hFile;
    }
    static String GetWindowsSystemErrorMessage (int iError)
    {
        char[] buf = new char[255];
        CharBuffer bb = CharBuffer.wrap (buf);
        //bb.clear ();
        //PointerByReference pMsgBuf = new PointerByReference ();
        int iChar = win32.FormatMessage (
                WinBase.FORMAT_MESSAGE_FROM_SYSTEM
                    //| WinBase.FORMAT_MESSAGE_IGNORE_INSERTS
                    //|WinBase.FORMAT_MESSAGE_ALLOCATE_BUFFER
                    ,
                null,
                iError,
                0x0804,
                bb, buf.length,
                //pMsgBuf, 0,
                null
            );
        //for (int i=0; i<iChar; i++)
        //{
        //  System.out.print (" ");
        //  System.out.print (String.format("%02X", buf[i]&0xFFFF));
        //}
        bb.limit (iChar);
        //System.out.print (bb);
        //System.out.print (pMsgBuf.getValue().getString(0));
        //win32.LocalFree (pMsgBuf.getValue());
        return bb.toString ();
    }

    public static void main (String[] args) throws Exception
    {
        if (args.length == 0)
        {
            System.out.println ("获取 Windows 的文件时间（创建时间、最后修改时间、最后访问时间）");
            System.out.println ("用法：");
            System.out.println ("   java -cp .;..;jna.jar;platform.jar WindowsFileTime [文件名1] [文件名2]...");
            return;
        }

        boolean rc;
        java.sql.Timestamp ct = new java.sql.Timestamp(0);
        java.sql.Timestamp wt = new java.sql.Timestamp(0);
        java.sql.Timestamp at = new java.sql.Timestamp(0);

        for (String sFileName : args)
        {
            System.out.println ("文件 " + sFileName);

            rc = GetFileTime (sFileName, ct, wt, at);
            if (rc)
            {
                System.out.println ("   创建时间：" + ct);
                System.out.println ("   修改时间：" + wt);
                System.out.println ("   访问时间：" + at);
            }
            else
            {
                //System.out.println ("GetFileTime 失败");
            }


            //wt.setTime (System.currentTimeMillis());
            wt = java.sql.Timestamp.valueOf("2010-07-23 00:00:00");
            rc = SetFileTime (sFileName, null, wt, null);
            if (rc)
            {
                System.out.println ("SetFileTime (最后修改时间) 成功");
            }
            else
            {
                //System.out.println ("SetFileTime 失败");
            }
        }
    }
}

Answer 3

我自己一直在研究这个问题，但我需要能够在Windows / * nix平台上运行的东西。

一个SO帖子包含一些指向Posix JNI implementations的链接。

• JNA-POSIX
• POSIX for Java

特别是，JNA-POSIX实现methods for getting file stats实现Windows，BSD，Solaris，Linux和OSX。

总而言之，它看起来非常有前景，所以我很快就会在我自己的项目上尝试它。

Answer 4

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class CreateDateInJava {
    public static void main(String args[]) {
        try {

            // get runtime environment and execute child process
            Runtime systemShell = Runtime.getRuntime();
            BufferedReader br1 = new BufferedReader(new InputStreamReader(System.in));
            System.out.println("Enter filename: ");
            String fname = (String) br1.readLine();
            Process output = systemShell.exec("cmd /c dir \"" + fname + "\" /tc");

            System.out.println(output);
            // open reader to get output from process
            BufferedReader br = new BufferedReader(new InputStreamReader(output.getInputStream()));

            String out = "";
            String line = null;

            int step = 1;
            while ((line = br.readLine()) != null) {
                if (step == 6) {
                    out = line;
                }
                step++;
            }

            // display process output
            try {
                out = out.replaceAll(" ", "");
                System.out.println("CreationDate: " + out.substring(0, 10));
                System.out.println("CreationTime: " + out.substring(10, 16) + "m");
            } catch (StringIndexOutOfBoundsException se) {
                System.out.println("File not found");
            }
        } catch (IOException ioe) {
            System.err.println(ioe);
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }
}

/**
D:\Foldername\Filename.Extension

Ex:
Enter Filename :
D:\Kamal\Test.txt
CreationDate: 02/14/2011
CreationTime: 12:59Pm

*/

Answer 5

javaxt-core库包含一个File类，可用于检索文件属性，包括创建时间。例如：

javaxt.io.File file = new javaxt.io.File("/temp/file.txt");
System.out.println("Created: " + file.getCreationTime());
System.out.println("Accessed: " + file.getLastAccessTime());
System.out.println("Modified: " + file.getLastModifiedTime());

适用于Java 1.5及更高版本。

Answer 6

我喜欢jGuru上的答案，其中列出了使用JNI获取答案的选项。这可能比炮轰更快，你可能会遇到其他需要专门为windows实现的情况。

此外，如果您需要移植到不同的平台，那么您也可以移植您的库，只需将它返回-1以获取* ix上此问题的答案。

Answer 7

这是使用BasicFileAttributes class：

的Java中的基本示例

   Path path = Paths.get("C:\\Users\\jorgesys\\workspaceJava\\myfile.txt");
    BasicFileAttributes attr;
    try {
      attr = Files.readAttributes(path, BasicFileAttributes.class);
      System.out.println("File creation time: " + attr.creationTime());
    } catch (IOException e) {
      System.out.println("oops un error! " + e.getMessage());
    }