Hutool 3.9 [cracked]

// Reads all lines from a UTF-8 file. Auto-closes. List<String> lines = FileUtil.readLines("config/users.txt", "UTF-8");

// Camel case to underscore (great for DB mapping) String dbField = StrUtil.toUnderlineCase("userFirstName"); // user_first_name Hutool 3.9

// With Hutool 3.9 String value = ObjectUtil.defaultIfNull(object.getString(), "default"); // Reads all lines from a UTF-8 file

Whether you are processing collections, scraping HTTP endpoints with HttpUtil , generating QR codes (yes, 3.9 supports basic QR via QrCodeUtil ), or just formatting dates – Hutool 3.9 makes Java feel like a modern, high-level language. implementation 'cn

implementation 'cn.hutool:hutool-all:3.9.0' There are no breaking changes in the public API between 3.8 and 3.9. You can drop in the new JAR and recompile. The only “gotcha” is that some deprecated methods (mostly from 3.1) were finally removed—check your logs for warnings. Comparing Hutool 3.9 vs. Hutool 5.x vs. Apache Commons | Feature | Hutool 3.9 | Hutool 5.8 (latest) | Apache Commons (Lang3 + IO) | | :--- | :--- | :--- | :--- | | JDK Baseline | Java 8 | Java 8+ (module support) | Java 8 | | External Dependencies | None | Optional (JSON, JWT) | None | | API Stability | Frozen (mature) | Evolving | Stable | | File Watching | Basic | WatchUtil (advanced) | No built-in | | Learning Curve | Low | Medium (many modules) | Medium (split across jars) | | Best For | Legacy projects, Simple JARs | New greenfield projects | Large enterprise |

// Get local IP address without parsing InetAddress String ip = NetUtil.getLocalhostStr(); // Check port availability boolean isOpen = NetUtil.isUsableLocalPort(8080); Upgrading is painless. If you are using Maven or Gradle:

If you want “what you see is what you get” and don’t want to worry about version clashes, stick with 3.9. If you need ExtraUtil for email or captcha generation, move to 5.x. Real-World Use Case: Replacing Utilities in a 500k LOC Legacy System We recently refactored a financial dashboard application. Originally, the codebase was a mess of SimpleDateFormat threadsafety issues and homemade StringUtil classes. We introduced Hutool 3.9 (not 5.x, to avoid permission issues with the security manager).