demo 很简单，只有两个文件

【1】、cargo.toml

[package]
name = "http_rust"
version = "0.1.0"
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
reqwest = { version = "0.11", features = ["json"] }
tokio = { version = "1", features = ["full"] }
serde_json = "1.0"

【2】、main.rs

use std::collections::HashMap;
use reqwest::header::HeaderMap;
use serde_json::value::Value;

#[tokio::main]
async fn main() {
    //get请求
  if let Ok(res)= get_calss_list_out_json().await{
       println!("{:#?}",res)
   };
     //get请求
  if let Ok(res)= get_calss_list_out_text().await{
    println!("{:#?}",res)
    };
    //    post传参加token请求
    //    if let Ok(res)=get_column_list().await{
    //        println!("{:#?}",res)
    //    }
  //post new 对象
    //    if let Ok(res)=get_other().await{
    //     println!("{:#?}",res)
    // }
   
}

//get请求不含token，输出json 格式
async fn get_calss_list_out_json()->Result<(),Box<dyn std::error::Error>>{
    let res=reqwest::get("http://example.url")
    .await?
    .json::<HashMap<String,Value>>()
    .await?;
    println!("{:#?}",res);
    Ok(())
}
// 输出 text 格式
async fn get_calss_list_out_text()->Result<(),reqwest::Error>{
    let res=reqwest::get("http://example.url")
    .await?
    .text()
    .await?;
    Ok(println!("{:#?}",res))
    
}

async fn get_column_list()->Result<HashMap<String, Value>, reqwest::Error>{
     // post 请求要创建client
     let client = reqwest::Client::new();

     // 组装header
     let mut headers = HeaderMap::new();
     headers.insert("Content-Type", "application/json".parse().unwrap());
     headers.insert("Authorization", "Bearer  token_in_here".parse().unwrap());
     // post 参数
      // 组装要提交的数据
    let mut data = HashMap::new();
    data.insert("params", "1");
    Ok(client.post("https://http://example.url").headers(headers).json(&data).send().await?.json::<HashMap<String, Value>>().await?)
}
 async fn get_other() -> Result<(),reqwest::Error> { 
            let mut data = HashMap::new();
            data.insert("params1", "1");
            data.insert("params2", "2");
            data.insert("params3", "{\"channel_name\":\"新闻广播\",\"logo\":\"\",\"desc\":\"123\"}");
            data.insert("compereName", "主持人");
            data.insert("status", "1");

        let res = reqwest::Client::new()       
         .post("http://example.url")     
         .json(&data) 
         .header("Content-Type", "application/x-www-form-urlencoded")     
         .header("Access-Control-Allow-Origin", "*")    
         .send()     
         .await?; 
         let text = res.text().await?;
         Ok(println!("{:#?}",text))
        
     }