轻量、实用、面向对象的 Java 工具库Lightweight, practical, object-oriented Java utilities.
AJ-Utils 是一个面向 Java 8 的模块化工具库，坚持面向对象设计与高质量代码，提供通用、I/O、HTTP、密码学、FTP、S3 对象存储和二维码等能力。A modular Java 8 utility library built with object-oriented design and high-quality code, providing common helpers, I/O, HTTP, cryptography, FTP, S3-compatible storage, and QR codes.
按需引入，职责清晰。Focused modules. Clear boundaries.
选择最贴合任务的组件，避免不必要的依赖。Use only the component you need and avoid unnecessary dependencies.
aj-util
核心工具库，提供字符串、集合、日期、JSON、XML、I/O、反射与密码学等通用能力。Core utilities for strings, collections, dates, JSON, XML, I/O, reflection and cryptography.
02 / HTTPaj-http
基于 HttpURLConnection 的同步 HTTP 请求组件，支持常用请求、表单、JSON 与文件传输。Synchronous HttpURLConnection-based requests, forms, JSON payloads and file transfer helpers.
03 / STORAGEaj-s3client
轻量 S3 兼容对象存储客户端，覆盖 SigV2、SigV4 与多个厂商实现。A focused S3-compatible storage client with SigV2, SigV4 and provider-specific implementations.
04 / FILE TRANSFERaj-ftp
面向纯 FTP 的轻量客户端，支持登录、上传、下载与传输进度。A lightweight plain-FTP client for login, uploads, downloads and transfer progress.
05 / QR CODEaj-qrcode
二维码生成组件，支持 PNG、SVG 等多种输出格式。QR-code generation with PNG, SVG and other output formats.
06 / IMAGEaj-image
图像处理组件，提供图片合成、缩放、裁剪与格式处理等能力。Image-processing helpers for composition, resizing, cropping and format handling.
经得起长期使用。Built for the long run.
所有组件均面向 Java 8 及以上环境。Every component targets Java 8 and later runtimes.
直观的 API 与实现，便于使用和维护。Straightforward APIs and implementations.
以清晰实现、代码注释、文档和单元测试，打造可靠、易维护的高质量代码。Clear implementations, comments, documentation and tests deliver reliable, maintainable, high-quality code.
以清晰的对象职责和抽象组织 API，方便扩展与复用。Clearly defined object responsibilities and abstractions make APIs easier to extend and reuse.
只引入需要的组件。Use only what your project needs.