Hutool 39 -

// Read file into a list of strings List lines = FileUtil.readLines("test.txt", "UTF-8"); // Copy a file FileUtil.copy("source.txt", "dest.txt", true); Use code with caution. Why "Hutool 39"?

Simplifies array creation, manipulation, and filtering without converting to collections first.

ImgUtil.scale(FileUtil.file("origin.jpg"), FileUtil.file("thumb.jpg"), 0.5f);

One night the grey-coated man came at the door with a key he claimed to have found. He left without force when Kai refused to open it, but the next morning Hutty’s cord was cut cleanly beside the bench. The device lay on the floor, the oilcloth empty, its eye a tiny dark stone. hutool 39

Contains pre-built regular expression patterns to validate common user inputs.

These fixes cover critical areas including , ensuring a more robust development experience.

Enhances standard Java Collections with easy join , filter , groupBy , and intersection/difference operations. Version 3.9 introduced safer null-handling for stream-like operations. // Read file into a list of strings List lines = FileUtil

Hutool is a "Swiss Army Knife" for Java developers. It was designed to reduce the need for repetitive "boilerplate" code. Instead of writing dozens of lines to read a file or send an HTTP request, Hutool allows you to accomplish these tasks with a single method call. The philosophy behind Hutool is simple: Core Modules in the 3.x Era

Hutool is a comprehensive Java utility library designed to simplify common development tasks through static method encapsulation, reducing the complexity of standard Java APIs. Released on June 23, 2025, represents a major step forward in modernizing the library with AI-driven capabilities and performance optimizations. 2. Key Features and Enhancements AI Integration ( hutool-ai )

Hutool 3.9.x is a legacy version (last updated ~2018). For new projects, use Hutool 5.x or 6.x . This document is for reference or maintenance of old systems. ImgUtil

| Feature | Description | |---------|-------------| | CollUtil.isEmpty() | Now supports null safely | | DateUtil.range() | Generate date ranges (daily, monthly) | | SecureUtil.hmacSha1() | HMAC-SHA1 support | | CsvUtil | Read/write CSV files | | ImgUtil.pressText() | Image watermarking | | ZipUtil.zip() | Recursive directory zip |

// 日期：格式化、偏移、比较 String now = DateUtil.now(); Date newDate = DateUtil.offsetDay(new Date(), 1); boolean sameDay = DateUtil.isSameDay(date1, date2);

// #6, #7: Collection handling List<User> users = CollUtil.newArrayList(); for (CsvRow row : rows) if (CollUtil.isEmpty(row)) continue;