如何在golang中从http请求中读取标头？

If I receive a request of type http.Request, how can I read the value of a specific header? In this case I want to pull the value of a jwt token out of the request header.

You can use the r.Header.Get:

func yourHandler(w http.ResponseWriter, r *http.Request) {
    ua := r.Header.Get("User-Agent")
    ...
}

package main

import (
    "fmt"
    "log"
    "net/http"
)

func main() {
    http.HandleFunc("/", handler)
    log.Fatal(http.ListenAndServe("localhost:8000", nil))
}

func handler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "%s %s %s 
", r.Method, r.URL, r.Proto)
    //Iterate over all header fields
    for k, v := range r.Header {
        fmt.Fprintf(w, "Header field %q, Value %q
", k, v)
    }

    fmt.Fprintf(w, "Host = %q
", r.Host)
    fmt.Fprintf(w, "RemoteAddr= %q
", r.RemoteAddr)
    //Get value for a specified token
    fmt.Fprintf(w, "

Finding value of \"Accept\" %q", r.Header["Accept"])
}

Connecting to http://localhost:8000/ from a browser will print the output in the browser.