Rust结构数组、序列化与反序列化

一、结构数组

const v0: i8 &＃61; 0;
const v1: i8 &＃61; 1;
const v2: i8 &＃61; 2;
const v3: i8 &＃61; 3;struct Arr {v: i8,s: &&＃39;static str,
}const str: [Arr; 4] &＃61; [Arr {v: v0, s:"zero",},Arr {v: v1, s:"one",},Arr {v: v2, s:"two",},Arr {v: v3, s:"three",},
];fn main() {println!("{}", str[2].v);
}


初始化一些方法&＃xff1a;
此方法安全&＃xff0c;但是效率不高&＃xff0c;会复制10份Foo { a: 10, b: 10}结构体。

#[derive(Copy, Clone, Debug)]
struct Foo {a: u32,b: u32,
}fn main() {let mut foo_array &＃61; [Foo { a: 10, b: 10 }; 10];
}


高效方法&＃xff1a;
Cargo.toml

...
[dependencies]
arrayvec &＃61; "0.4.10"


main.rs

use arrayvec::ArrayVec;
use std::iter;#[derive(Clone)]
struct Foo {a: u32,b: u32,
}fn main() {let foo_array: [Foo; 10] &＃61; iter::repeat(Foo { a: 10, b: 10 }).collect::<ArrayVec<_>>().into_inner().unwrap_or_else(|_| unreachable!());
}


或者

struct Foo {foo: isize,
}impl Foo {pub fn new(i: isize) -> Foo {//do stuff with iFoo { foo: i }}
}fn main() {//this was my best guess...let foo_array: [Foo; N] &＃61; [0..N].iter().map(|i| Foo::new(i));
}


二、序列化

Rust Crate 使用&＃xff1a;serde
序列化和反序列化是非常通用的功能&＃xff0c;在网络传输&＃xff0c;数据存储上极其常见的。序列化和反序列化的通用解释是&＃xff1a;

seriallization 序列化 &＃xff1a; 将对象转化为便于传输的格式&＃xff0c; 常见的序列化格式&＃xff1a;二进制格式&＃xff0c;字节数组&＃xff0c;json字符串&＃xff0c;xml字符串。
deseriallization 反序列化&＃xff1a;将序列化的数据恢复为对象的过程。

格式编写者只需实现 Serde 的 trait 即可&＃xff0c;而用户通过#[derive(Serialize&＃xff0c;Deserialize)]对其对象进行序列化&＃xff0c;而无需考虑格式。

Cargo.toml

...
[dependencies]
serde &＃61; { version &＃61; "1.0", features &＃61; ["derive"] }
serde_json &＃61; "1.0.0"
...


use serde::{Serialize, Deserialize};#[derive(Serialize, Deserialize)]
struct Person {name: String,age: u8,phones: Vec<String>,weight: Option<u8>,
}fn main() {let data &＃61; r#"{"name": "John Doe","age": 43,"phones": ["&＃43;44 1234567","&＃43;44 2345678"]}"#;// 解析字符串到Person对象。let p: Person &＃61; serde_json::from_str(data).unwrap();println!("Please call {} at the number {}", p.name, p.phones[0]);// Person对象转为JSON字符串.let serialized &＃61; serde_json::to_string(&p).unwrap();println!("serialized &＃61; {}", serialized);
}


关于更多&＃xff1a;https://blog.logrocket.com/rust-serialization-whats-ready-for-production-today/

三、反序列化

use serde_json;
use std::result::Result;
use std::error::Error;
use serde::{Deserialize, Serialize};#[derive(Debug, Serialize, Deserialize)]
#[serde(untagged)]
enum Speech {Str(String),StrArray(Vec<String>),
}#[derive(Debug, Serialize, Deserialize)]
struct Foo {pub foo: String,#[serde(skip_serializing_if &＃61; "Option::is_none")]speech: Option<Speech>,
} fn main() -> Result<(), Box<dyn Error>> {let json1 &＃61; r#"{"foo": "bar","speech": "something"}"#; let json2 &＃61; r#"{"foo": "bar","speech": ["something", "something else"]}"#; let json3 &＃61; r#"{"foo": "bar"}"#; let foo1: Foo &＃61; serde_json::from_str(json1)?;let back_to_str_foo1 &＃61; serde_json::to_string(&foo1).unwrap();println!("foo1 {:#?}", foo1);println!("back_to_str_foo1 {}", back_to_str_foo1);let foo2: Foo &＃61; serde_json::from_str(json2)?;let back_to_str_foo2 &＃61; serde_json::to_string(&foo2).unwrap();println!("foo1 {:#?}", foo2);println!("back_to_str_foo2 {}", back_to_str_foo2);let foo3: Foo &＃61; serde_json::from_str(json3)?;let back_to_str_foo3 &＃61; serde_json::to_string(&foo3).unwrap();println!("foo1 {:#?}", foo3);println!("back_to_str_foo3 {}", back_to_str_foo3);Ok(())
}