此crate提供可以用于任何struct或enum实现的[FromFile]特质。实现后，您将获得一个from_file方法，允许您跳过从磁盘读取文件并选择正确的serde方法——这将是根据文件扩展名自动完成的。

快速预览

所有示例都需要也生成serde Deserialize的特质。 (下面提供复制粘贴示例)

#[derive(Deserialize)]
struct Person {
    name: String
}

impl FromFile for Person {}

fn main() {
    let path = "test/fixtures/person.json";
    let person = Person::from_file(path).expect("deserialize from file");
    assert_eq!(person.name, String::from("Shane"));
}

带有from_file_derive的快速预览

这需要额外的crate from_file_derive

#[derive(Deserialize, FromFile)]
struct Person {
    name: String
}

fn main() {
    let path = "test/fixtures/person.json";
    let person = Person::from_file(path).expect("deserialize from file");
    assert_eq!(person.name, String::from("Shane"));
}

复制/粘贴示例

#[macro_use]
extern crate serde_derive;
extern crate serde;

#[macro_use]
extern crate from_file_derive;

use from_file::FromFile;

#[derive(Deserialize, FromFile)]
struct Person {
    name: String
}

fn main() {
    let path = "test/fixtures/person.json";
    let person = Person::from_file(path).expect("deserialize from file");
    assert_eq!(person.name, String::from("Shane"));
}

带有导入和错误处理的完整示例

#[macro_use]
extern crate serde_derive;

#[macro_use]
extern crate from_file_derive;
extern crate from_file;

use from_file::FromFile;

#[derive(Deserialize, FromFile, Debug, PartialEq)]
struct Person {
    name: String,
    age: usize
}

fn main() {
    match Person::from_file("test/fixtures/person.json") {
        Ok(p) => println!("Got a Person from a file!"),
        Err(e) => eprintln!("{}", e)
    }
}