java 文件重命名

public static void main(String[] args) {、
//定义一个文件名
    String fileName = "asdmajnfijasngojds.png";
// 将文件名 随机，去除其中的- 拼接文件后缀
    System.out.println(UUID.randomUUID().toString().replace("-","")+"."+getFormatName(fileName));
}

private static String getFormatName(String name) {
    if (StrUtil.isBlank(name)) {
        return "jpg";
    }
    try {
        String formatName = null;
        int l = name.lastIndexOf(".");
        if (l <= 0 || l + 1 >= name.length()) {
            return "jpg";
        }
        formatName = name.substring(l + 1, name.length());
        formatName = formatName.toLowerCase();
        return formatName;
    } catch (Exception e) {
        e.printStackTrace();
        return "jpg";
    }
}