Defhop · Java 代码导航助手
跳转定义 · 查找引用 · 读代码更快
中文
这是什么
Defhop = Java 助手，专注一件事：代码导航。
- 跳转定义（Go to Definition /
F12）
- 查找引用（Find References）
- 方法实现、继承关系
- MyBatis / Spring / Feign / Lombok / MapStruct 等场景的跨文件跳转
适合在大项目里 看代码、追调用、读懂别人写的逻辑——尤其是你已经用 AI 写代码，只想要一个又快又轻的「跳过去」工具。
核心引擎用 Go 编写：原生多核解析 Java 源码，不依赖 JVM 跑语言服务，体积小、内存省、跳转快。
不做代码补全、不做重构、不做一堆 IDE 全家桶。保持精简，打开快、跳得快。
由来
AI 时代，写代码越来越少靠人肉敲：生成、改写、补洞多半交给助手。以前视为标配的 代码提示、重构，反而常常变成编辑器里的负担——又重、又抢资源，还和 AI 能力大量重叠。
但人还是要 偶尔看代码：追调用、核对实现、弄清某段逻辑从哪来。这时最需要的是轻快的 跳转与引用，而不是再背一整套 IDE。
VS Code 里常见的 Java 跳转往往要 复杂配置（JDK、语言服务、项目导入……），体感却仍不稳定。于是有了 开箱即用 的 Defhop：装上就能导航，专注读代码这一件事。
想要的能力，欢迎到 GitHub 许愿 / 提 Issue：
→ github.com/iCodZilla/defhop
请我喝杯咖啡
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性能实测（Go 引擎）
本机 Windows 实测（2026-10-27）。解析与导航均在 Go 后端完成；下表只按规模列举（多模块 Maven 工程），不含项目名称。
| 规模 |
文件 / 模块 |
冷索引 |
跳转定义 DEF |
工作集内存 |
引擎体积 |
| 小型 |
~20 个 .java |
~13 ms |
p95 ~1 ms |
~14 MB |
5.66 MB |
| 中型 |
~570 个 .java · ~10 个一级模块（约 14 个 Maven 模块） |
~0.3 s |
p95 ~2 ms |
~70 MB |
同上 |
| 大型 |
~9,000 个 .java · ~10 个一级模块（约 60 个 Maven 模块）· ~10 万 symbols |
~9 s |
p95 ~1 ms |
~830 MB |
同上 |
读法：中型仓亚秒级就绪；近万文件级约数秒完成索引；跳转保持毫秒级；内存是导航引擎占用，不是再挂一整套 JVM Language Server。
为什么选 Defhop
| 你在意的 |
Defhop |
| Go 解析 |
原生编译、多核吃满，不为导航再拉起 JVM |
| 占用低 |
单引擎约数 MB～百 MB 级，见上表实测 |
| 效率高 |
冷索引 / 热更新 / F12 均为毫秒～百毫秒级 |
| 够用就好 |
只做导航，不和 AI 补全抢活 |
| 框架懂行 |
Spring、MyBatis、Feign 等按需启用 |
支持能力
基础导航（始终可用）
- 类 / 方法 / 字段 → 定义
- 查找引用、查找实现
- 适合日常读 Java 源码
框架增强（检测到才加载）
| 场景 |
你能跳到哪里 |
| Spring |
@Value、配置属性 ↔ application.yml 等 |
| MyBatis |
Mapper 方法 ↔ XML SQL |
| OpenFeign |
Feign 接口 ↔ Controller |
| Lombok |
生成出来的成员也能跳 |
| MapStruct |
映射方法 / @Mapping 目标字段 |
没用到的框架不会白占资源。
怎么用
- 从扩展市场安装 Defhop for Java，重新加载窗口
- 打开你的 Maven / Gradle Java 项目
- 看右下角索引进度，完成后即可导航
- 光标放在符号上 →
F12 跳转定义，或右键 查找引用
常用命令（命令面板搜 Defhop）：
- Reindex Workspace — 重新索引
- Go to MyBatis SQL — 从 Java 跳到 Mapper XML
- Go to Java Declaration — 从 XML 跳回 Java
和「大型 Java 插件」的区别
|
传统 Java 套件 |
Defhop |
| 定位 |
补全 + 重构 + 调试 + … |
Java 导航助手 |
| 引擎 |
常依赖 JVM Language Server |
Go 原生解析，无 JVM |
| 体感 |
功能全，往往更重 |
功能少，专注速度 |
| AI 时代 |
大量能力和 AI 重叠 |
互补：AI 负责写，Defhop 负责读与跳 |
English
What it is
Defhop is a Java navigation helper: Go to Definition, Find References, implementations, and smart jumps across Spring / MyBatis / Feign / Lombok / MapStruct.
The indexer and navigation engine are written in Go—native multi-core parsing, no JVM required to run the nav backend. Small binary, low RAM, fast hops.
Built for reading code in large repos—especially when AI already writes the code and you just need to hop around fast.
No completion. No refactoring. No full IDE suite. Just navigation—fast and lean.
Why it exists
In the AI era, people write far less code by hand—assistants draft, rewrite, and patch. Features that once felt essential—completion and refactoring—often become dead weight: heavy, resource-hungry, and largely overlapping with AI.
You still need to read code sometimes: follow a call, check an implementation, see where logic comes from. What you want then is snappy go-to-definition / references, not another full IDE stacked on VS Code.
Stock Java navigation in VS Code usually means painful setup (JDK, language server, project import…) with uneven results. Defhop is the out-of-the-box alternative: install and navigate—built only for reading code.
Wish-list welcome on GitHub:
→ github.com/iCodZilla/defhop
Buy me a coffee
| Alipay |
WeChat Pay |
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Benchmarks (Go engine)
Measured on Windows (2026-10-27). Parsing & navigation run in the Go backend. Rows are by scale only (multi-module Maven workspaces)—no project names.
| Scale |
Files / modules |
Cold index |
Go to Definition |
Working set |
Engine binary |
| Small |
~20 .java |
~13 ms |
p95 ~1 ms |
~14 MB |
5.66 MB |
| Medium |
~570 .java · ~10 top-level modules (~14 Maven modules) |
~0.3 s |
p95 ~2 ms |
~70 MB |
same |
| Large |
~9,000 .java · ~10 top-level modules (~60 Maven modules) · ~100k symbols |
~9 s |
p95 ~1 ms |
~830 MB |
same |
Takeaway: medium repos are ready in under a second; ~10k-file workspaces index in a few seconds; jumps stay around 1–2 ms; RAM is the nav engine—not a second full JVM language server.
Why Defhop
| You care about |
Defhop |
| Go parser |
Native, multi-core—no JVM just to navigate |
| Low footprint |
Single-digit to low-hundreds MB—see table |
| High throughput |
Cold / warm / F12 in ms–hundreds of ms |
| Stay lean |
Navigation only—won't fight your AI assistant |
| Frameworks |
Spring, MyBatis, Feign… on demand |
Capabilities
Core navigation
- Types / methods / fields → definition
- References & implementations
On-demand framework jumps
|
|
| Spring |
@Value / config props ↔ YAML & friends |
| MyBatis |
Mapper ↔ XML SQL |
| OpenFeign |
Feign API ↔ Controller |
| Lombok |
Generated members |
| MapStruct |
Mappings & targets |
How to use
- Install Defhop for Java and reload
- Open a Maven / Gradle Java workspace
- Wait for the status-bar index
F12 / Find References
Command Palette → search Defhop for reindex and MyBatis ↔ Java routes.
vs full Java packs
|
Classic Java packs |
Defhop |
| Role |
Full IDE features |
Java navigation helper |
| Engine |
Often a JVM language server |
Go-native parser, no JVM |
| Feel |
Complete, often heavy |
Focused, fast |
| AI era |
Overlaps assistants |
Complement: AI writes, Defhop jumps |
Defhop for Java · Java 导航 · 跳转定义 · 查找引用
GitHub 许愿 / Feature requests
