有没有更好的方法摆脱目录遍历攻击？

Question

我正在尝试防止对我的项目进行目录遍历攻击，但我不知道这有什么问题

public static final String validateOnDiskFilePath(final String absoluteFolderPath, final String child) {
    String absolutePath = null;
    try {
        String filePath = absoluteFolderPath + File.separator +child;
        absolutePath = new File(absoluteFolderPath, child).getCanonicalPath();
        if (!absolutePath.startsWith(filePath)) {
            throw new SecureStorageException(MessageFormat.format("Invalid path constructed! path ={0}, absolutePath ={1}", filePath, absolutePath));
        }
    }catch(IOException ie){
        throw new SecureStorageException("Failed to get the absolutePath", ie);
    }
    return absolutePath;
}

public static final String validateOnDiskFilePath(final String absoluteFolderPath) {
    String absolutePath = null;
    try {
        absolutePath = new File(absoluteFolderPath).getCanonicalPath();
        if (!absolutePath.startsWith(absoluteFolderPath)) {
            throw new SecureStorageException(MessageFormat.format("Invalid path constructed! path ={0}, absolutePath ={1}", absoluteFolderPath, absolutePath));
        }
    }catch(IOException ie){
        throw new SecureStorageException("Failed to get the absolutePath", ie);
    }
    return absolutePath;
}