Java中的Windows快捷方式（.lnk）解析器？

添加了注释（到目前为止，对每个贡献者的一些解释以及功劳），对文件魔术的额外检查，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），修复以抛出带有适当消息的ParseException而不是ArrayIndexOutOfBoundsException，如果文件太小， 做了一些一般的清理。

此处的源代码（如果您有任何更改，请直接将它们推送到 GitHub 存储库/项目。

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);
    }

}

Sam Brightman 的解决方案仅适用于本地文件。我添加了对网络文件的支持：

• Java中的Windows快捷方式（.lnk）解析器？
• http://code.google.com/p/8bits/downloads/detail?name=The_Windows_Shortcut_File_Format.pdf

• http://www.javafaq.nu/java-example-code-468.html

  public class LnkParser {
  
  public LnkParser(File f) throws IOException {
      parse(f);
  }
  
  private boolean isDirectory;
  private boolean isLocal;
  
  public boolean isDirectory() {
      return isDirectory;
  }
  
  private String real_file;
  
  public String getRealFilename() {
      return real_file;
  }
  
  private void parse(File f) throws IOException {
      // read the entire file into a byte buffer
      FileInputStream fin = new FileInputStream(f);
      ByteArrayOutputStream bout = new ByteArrayOutputStream();
      byte[] buff = new byte[256];
      while (true) {
          int n = fin.read(buff);
          if (n == -1) {
              break;
          }
          bout.write(buff, 0, n);
      }
      fin.close();
      byte[] link = bout.toByteArray();
  
      parseLink(link);
  }
  
  private void parseLink(byte[] link) {
      // 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 = bytes2short(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;
      }
  }
  
  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 bytes2short(byte[] bytes, int off) {
      return ((bytes[off + 1] & 0xff) << 8) | (bytes[off] & 0xff);
  }
  
  /**
   * Returns the value of the instance variable 'isLocal'.
   *
   * @return Returns the isLocal.
   */
  public boolean isLocal() {
      return isLocal;
  }
  }