Rust for Java Programmers | Rust 面向 Java 程序员

Data Structures and Collections
数据结构与集合

What you’ll learn: How Rust models data with tuples, arrays, slices, structs, and standard collections, and how those choices compare to Java classes and collection interfaces.
本章将学习： Rust 如何用元组、数组、切片、结构体和标准集合来建模数据，以及这些选择和 Java 的 class、集合接口体系有什么差别。

Difficulty: 🟢 Beginner
难度： 🟢 初级

Rust data modeling is lighter than Java’s object-oriented default. There is less ceremony, but also less hidden behavior.
Rust 的数据建模比 Java 默认的面向对象风格更轻。仪式感更少，隐藏行为也更少。

Tuples
元组

#![allow(unused)]
fn main() {
let pair = ("Ada", 42);
let (name, score) = pair;
}

Tuples are useful for temporary groupings. If the fields need names, move to a struct.
元组适合临时打包几个值。如果字段需要名字，就该升级成 struct 了。

Arrays and Slices
数组与切片

An array in Rust has length as part of its type. A slice is the borrowed view over contiguous elements.
Rust 数组会把长度写进类型里。slice 则是对连续元素的一段借用视图。

Structs vs Classes
结构体与类

#![allow(unused)]
fn main() {
struct User {
    id: u64,
    name: String,
}
}

Rust structs hold data. Methods live separately in impl blocks. There is no hidden inheritance tree around them.
Rust struct 主要承载数据，方法放在单独的 impl 块里。它背后没有一整棵默认继承树跟着跑。

Standard Collections
标准集合

Rust standard collections are concrete types rather than interface-first abstractions.
Rust 标准集合更偏向具体类型，而不是先上接口再谈实现。

Why This Matters
这意味着什么

Java code often starts with interfaces and containers. Rust code often starts with concrete data structures and only introduces abstraction when the need becomes real.
Java 代码经常从接口和容器开始，Rust 代码则更常从具体数据结构起步，等抽象需求真的出现时再加一层。

Advice
建议

• use tuples for short-lived grouped values
  短生命周期的分组值用 tuple。
• use structs for domain data
  领域数据优先用 struct。
• use slices for read-only borrowed views into arrays or vectors
  只读借用视图优先用 slice。
• begin with Vec and HashMap; optimize later if the workload demands it
  先把 Vec 和 HashMap 用顺，真的有性能压力再优化。

Rust’s data model is simple on purpose. That simplicity is one of the reasons ownership stays tractable.
Rust 的数据模型是故意做得简单，这种简单也是所有权还能维持可理解性的原因之一。