Hutool 3.9 Upd -

// 2. Network - Fetch with retry String result = HttpUtil.createGet("https://api.ipify.org") .timeout(5000) .execute() .body(); // 3. Image - QR code generation QrCodeUtil.generate("https://hutool.cn", 300, 300, FileUtil.file("qr.png")); // 4. Reflection - Deep copy with ignore User user = new User("John"); User copy = BeanUtil.copyProperties(user, User.class, "id"); // 5. Number - Radix conversion String binary = NumberUtil.toBinaryString(255); // "11111111" String hex = NumberUtil.toHexString(255); // "ff"

CronUtil.schedule("0 0 2 * * *", () -> FileUtil.clean(FileUtil.file("/temp/logs")); ); CronUtil.start(); // Runs a lightweight cron scheduler inside your JVM. The IdUtil module got objectId() – a MongoDB-like 12-byte ID generator, perfect for distributed logging without database sequences. Part 7: Common Pitfalls and Solutions in Hutool 3.9 UPD Pitfall 1: ClassCastException in Convert.convert() Cause: Using raw types. Solution: Always parameterize: Convert.convert(List.class, myObject) → Convert.convert(new TypeReference<List<String>>(){}, myObject) . Pitfall 2: Timezone Hell in DateUtil.beginOfDay() Fix: Use DateUtil.beginOfDay(date, TimeZone.getTimeZone("GMT+8")) . Pitfall 3: FileUtil.readLines() Memory Bloat Solution: For large files (>50 MB), use FileUtil.readUtf8Lines(File, LineConsumer ) streaming consumer introduced in 3.9 UPD. Part 8: Hutool 3.9 vs. Modern Java (17+) – Is It Still Worth It? With Java 17 introducing String::formatted , List::copyOf , and Files.writeString() , some argue Hutool is redundant. They are wrong. Here’s why Hutool 3.9 UPD still wins: Hutool 3.9 UPD

| Feature | Java 17 JDK | Hutool 3.9 UPD | | :--- | :--- | :--- | | | Requires JavaMail + manual MIME | MailUtil.send() one-liner | | Captcha generation | Zero support | CaptchaUtil.createLineCaptcha() | | Tree structure building | Manual recursion | TreeUtil.build(list, "0") | | Parameter validation | Hibernate or manual | Validator.isChinese(name) | Reflection - Deep copy with ignore User user