# 参数提取
## 查询参数 (`#[q]`)
使用 `#[q]` 属性自动提取查询参数：
```rust
#[get("/search")]
async fn search(#[q] query: String, #[q] page: Option<i32>) -> String {
format!("Search: {}, Page: {:?}", query, page)
}
// 支持元组模式
#[get("/search2")]
async fn search2(#[q] (query, page): (String, Option<i32>)) -> String {
format!("Search: {}, Page: {:?}", query, page)
}
```
## 请求体 (`#[b]`)
使用 `#[b]` 属性处理请求体，支持多种格式：
```rust
use serde::Deserialize;
#[derive(Deserialize)]
struct User {
name: String,
age: i32,
}
// JSON 格式（默认）
#[post("/users")]
async fn create_user(#[b] user: User) -> String {
format!("Created user: {:?}", user)
}
// Form 格式
#[post("/users/form")]
async fn create_user_form(#[b(form)] user: User) -> String {
format!("Created user from form: {:?}", user)
}
// Multipart 格式
#[post("/users/upload")]
async fn upload_user(#[b(multipart)] user: User) -> String {
format!("Uploaded user: {:?}", user)
}
// 可选参数
#[post("/users/optional")]
async fn create_user_optional(#[b] user: Option<User>) -> String {
match user {
Some(u) => format!("Created user: {:?}", u),
None => "No user provided".to_string(),
}
}
```