Java 判断符号链接

  /**
     * Determines whether the specified file is a Symbolic Link rather than an actual file.
     * <p>
     * Will not return true if there is a Symbolic Link anywhere in the path,
     * only if the specific file is.
     * <p>
     * <b>Note:</b> the current implementation always returns {@code false} if the system
     * is detected as Windows using {@link FilenameUtils#isSystemWindows()}
     * <p>
     * For code that runs on Java 1.7 or later, use the following method instead:
     * <br>
     * {@code boolean java.nio.file.Files.isSymbolicLink(Path path)}
     * @param file the file to check
     * @return true if the file is a Symbolic Link
     * @throws IOException if an IO error occurs while checking the file
     * @since 2.0
     */
    public static boolean isSymlink(final File file) throws IOException {
        if (file == null) {
            throw new NullPointerException("File must not be null");
        }
        if (FilenameUtils.isSystemWindows()) {
            return false;
        }
        File fileInCanonicalDir = null;
        if (file.getParent() == null) {
            fileInCanonicalDir = file;
        } else {
            final File canonicalDir = file.getParentFile().getCanonicalFile();
            fileInCanonicalDir = new File(canonicalDir, file.getName());
        }

        if (fileInCanonicalDir.getCanonicalFile().equals(fileInCanonicalDir.getAbsoluteFile())) {
            return false;
        } else {
            return true;
        }
    }

ref: http://svn.apache.org/viewvc/commons/proper/io/trunk/src/main/java/org/apache/commons/io/FileUtils.java?view=markup