Java中的Windows快捷方式(.lnk)解析器?

我目前正在使用Win32ShellFolderManager2ShellFolder.getLinkLocation解析Java中的Windows快捷方式。不幸的是,如果Java程序在Vista下作为服务运行getLinkLocation,则无法使用。具体来说,我得到一个异常,指出“无法获取外壳文件夹ID列表”。

搜索网络确实会提及此错误消息,但始终与关联JFileChooser。我没有使用JFileChooser,我只需要将.lnk文件解析到其目的地即可。

有人知道.lnk我可以使用用Java编写的文件的第三方解析器吗?

此后,我在这里找到了.lnk格式的非官方文档,但是如果有人以前做过,我宁愿不必做这项工作,因为该格式相当可怕。

回答:

添加了注释(到目前为止有一些说明以及对每个贡献者的感谢),对文件魔术的附加检查,快速测试以查看给定文件是否可能是有效链接(不读取所有字节),进行了抛出的修复如果文件太小,则使用适当的消息而不是ArrayIndexOutOfBoundsException的ParseException进行一些常规清理。

在此处提供源代码(如果有任何更改,请将其直接推到GitHub repo / project。

package org.stackoverflowusers.file;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.text.ParseException;

/**

* Represents a Windows shortcut (typically visible to Java only as a '.lnk' file).

*

* Retrieved 2011-09-23 from http://stackoverflow.com/questions/309495/windows-shortcut-lnk-parser-in-java/672775#672775

* Originally called LnkParser

*

* Written by: (the stack overflow users, obviously!)

* Apache Commons VFS dependency removed by crysxd (why were we using that!?) https://github.com/crysxd

* Headerified, refactored and commented by Code Bling http://stackoverflow.com/users/675721/code-bling

* Network file support added by Stefan Cordes http://stackoverflow.com/users/81330/stefan-cordes

* Adapted by Sam Brightman http://stackoverflow.com/users/2492/sam-brightman

* Based on information in 'The Windows Shortcut File Format' by Jesse Hager <jessehager@iname.com>

* And somewhat based on code from the book 'Swing Hacks: Tips and Tools for Killer GUIs'

* by Joshua Marinacci and Chris Adamson

* ISBN: 0-596-00907-0

* http://www.oreilly.com/catalog/swinghks/

*/

public class WindowsShortcut

{

private boolean isDirectory;

private boolean isLocal;

private String real_file;

/**

* Provides a quick test to see if this could be a valid link !

* If you try to instantiate a new WindowShortcut and the link is not valid,

* Exceptions may be thrown and Exceptions are extremely slow to generate,

* therefore any code needing to loop through several files should first check this.

*

* @param file the potential link

* @return true if may be a link, false otherwise

* @throws IOException if an IOException is thrown while reading from the file

*/

public static boolean isPotentialValidLink(File file) throws IOException {

final int minimum_length = 0x64;

InputStream fis = new FileInputStream(file);

boolean isPotentiallyValid = false;

try {

isPotentiallyValid = file.isFile()

&& file.getName().toLowerCase().endsWith(".lnk")

&& fis.available() >= minimum_length

&& isMagicPresent(getBytes(fis, 32));

} finally {

fis.close();

}

return isPotentiallyValid;

}

public WindowsShortcut(File file) throws IOException, ParseException {

InputStream in = new FileInputStream(file);

try {

parseLink(getBytes(in));

} finally {

in.close();

}

}

/**

* @return the name of the filesystem object pointed to by this shortcut

*/

public String getRealFilename() {

return real_file;

}

/**

* Tests if the shortcut points to a local resource.

* @return true if the 'local' bit is set in this shortcut, false otherwise

*/

public boolean isLocal() {

return isLocal;

}

/**

* Tests if the shortcut points to a directory.

* @return true if the 'directory' bit is set in this shortcut, false otherwise

*/

public boolean isDirectory() {

return isDirectory;

}

/**

* Gets all the bytes from an InputStream

* @param in the InputStream from which to read bytes

* @return array of all the bytes contained in 'in'

* @throws IOException if an IOException is encountered while reading the data from the InputStream

*/

private static byte[] getBytes(InputStream in) throws IOException {

return getBytes(in, null);

}

/**

* Gets up to max bytes from an InputStream

* @param in the InputStream from which to read bytes

* @param max maximum number of bytes to read

* @return array of all the bytes contained in 'in'

* @throws IOException if an IOException is encountered while reading the data from the InputStream

*/

private static byte[] getBytes(InputStream in, Integer max) throws IOException {

// read the entire file into a byte buffer

ByteArrayOutputStream bout = new ByteArrayOutputStream();

byte[] buff = new byte[256];

while (max == null || max > 0) {

int n = in.read(buff);

if (n == -1) {

break;

}

bout.write(buff, 0, n);

if (max != null)

max -= n;

}

in.close();

return bout.toByteArray();

}

private static boolean isMagicPresent(byte[] link) {

final int magic = 0x0000004C;

final int magic_offset = 0x00;

return link.length >= 32 && bytesToDword(link, magic_offset) == magic;

}

/**

* Gobbles up link data by parsing it and storing info in member fields

* @param link all the bytes from the .lnk file

*/

private void parseLink(byte[] link) throws ParseException {

try {

if (!isMagicPresent(link))

throw new ParseException("Invalid shortcut; magic is missing", 0);

// get the flags byte

byte flags = link[0x14];

// get the file attributes byte

final int file_atts_offset = 0x18;

byte file_atts = link[file_atts_offset];

byte is_dir_mask = (byte)0x10;

if ((file_atts & is_dir_mask) > 0) {

isDirectory = true;

} else {

isDirectory = false;

}

// if the shell settings are present, skip them

final int shell_offset = 0x4c;

final byte has_shell_mask = (byte)0x01;

int shell_len = 0;

if ((flags & has_shell_mask) > 0) {

// the plus 2 accounts for the length marker itself

shell_len = bytesToWord(link, shell_offset) + 2;

}

// get to the file settings

int file_start = 0x4c + shell_len;

final int file_location_info_flag_offset_offset = 0x08;

int file_location_info_flag = link[file_start + file_location_info_flag_offset_offset];

isLocal = (file_location_info_flag & 2) == 0;

// get the local volume and local system values

//final int localVolumeTable_offset_offset = 0x0C;

final int basename_offset_offset = 0x10;

final int networkVolumeTable_offset_offset = 0x14;

final int finalname_offset_offset = 0x18;

int finalname_offset = link[file_start + finalname_offset_offset] + file_start;

String finalname = getNullDelimitedString(link, finalname_offset);

if (isLocal) {

int basename_offset = link[file_start + basename_offset_offset] + file_start;

String basename = getNullDelimitedString(link, basename_offset);

real_file = basename + finalname;

} else {

int networkVolumeTable_offset = link[file_start + networkVolumeTable_offset_offset] + file_start;

int shareName_offset_offset = 0x08;

int shareName_offset = link[networkVolumeTable_offset + shareName_offset_offset]

+ networkVolumeTable_offset;

String shareName = getNullDelimitedString(link, shareName_offset);

real_file = shareName + "\\" + finalname;

}

} catch (ArrayIndexOutOfBoundsException e) {

throw new ParseException("Could not be parsed, probably not a valid WindowsShortcut", 0);

}

}

private static String getNullDelimitedString(byte[] bytes, int off) {

int len = 0;

// count bytes until the null character (0)

while (true) {

if (bytes[off + len] == 0) {

break;

}

len++;

}

return new String(bytes, off, len);

}

/*

* convert two bytes into a short note, this is little endian because it's

* for an Intel only OS.

*/

private static int bytesToWord(byte[] bytes, int off) {

return ((bytes[off + 1] & 0xff) << 8) | (bytes[off] & 0xff);

}

private static int bytesToDword(byte[] bytes, int off) {

return (bytesToWord(bytes, off + 2) << 16) | bytesToWord(bytes, off);

}

}

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