Hutool-http is often preferred over heavier libraries like Apache HttpClient for its simplicity. In 3.9, several refinements were made to the HttpRequest and HttpResponse classes:
The blank() method in 3.9 had been "optimized" to handle certain Unicode spaces more aggressively. But in doing so, it now called toString() on a CharSequence before checking if the input was null. If the input was null, it exploded.
With Java 17 introducing String::formatted , List::copyOf , and Files.writeString() , some argue Hutool is redundant. Here’s why Hutool 3.9 UPD still wins: Hutool 3.9 UPD
// Hutool 3.9 UPD example int[] intArray = 1, 2, 3; String str = Convert.toStr(intArray); // Previously returned null; now returns "[1, 2, 3]"
I believe you're asking about and what were the good/notable features in that update. Hutool-http is often preferred over heavier libraries like
Hutool 3.9 enhanced FileUtil and IoUtil to handle file operations, such as reading, writing, and copying, more efficiently, reducing memory overhead during large file processing. Quickly reading a file's content into a string:
import cn.hutool.core.date.DateUtil; import java.util.Date; public class DateExample public static void main(String[] args) // Parse a standard date string automatically Date date = DateUtil.parse("2026-05-28 20:15:00"); // Calculate an offset of three days forward Date threeDaysLater = DateUtil.offsetDay(date, 3); // Output a highly readable string format System.out.println("Future Date: " + DateUtil.formatDateTime(threeDaysLater)); Use code with caution. Example B: Secure MD5 Hashing If the input was null, it exploded
Security is paramount. The 3.9 UPD updates strengthened SecureUtil , providing easier access to common algorithms like AES, DES, and RSA. AES encryption:
3.9 introduced more flexible CopyOptions , allowing developers to ignore specific properties or handle null values with greater precision during bean copying.
He decided to call it . The ".UPD" stood for "Urgent Performance & Defect"—a break from the semantic versioning tradition. It wouldn't add new features. It would promise only one thing: making the old version do what it was always supposed to do.
Hutool is designed as a modular library, allowing developers to import specific tools or the entire suite via the Hutool-all package :