go 1.17

http
easyjson  #github上的一个rest_decode项目
http_router
restful01

go_http

package main

import (
	"fmt"
	"net/http"

	"time"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "Hello World!")
	})
	http.HandleFunc("/time/", func(w http.ResponseWriter, r *http.Request) {
		t := time.Now()
		timeStr := fmt.Sprintf("{\"time\": \"%s\"}", t)
		w.Write([]byte(timeStr))
	})

	http.ListenAndServe(":8080", nil)
}

简要：
http.ListenAndServe 函数负责监听8080端口，建立连接
http.HandleFunc  处理请求，它拥有w，r两个参数，w负责客户端应答，r负责接收客户端请求

http_router
https://github.com/joshbuddy/http_router
go get -u  github.com/julienschmidt/httprouter

package main

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

	"github.com/julienschmidt/httprouter"
)

func Index(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
	fmt.Fprint(w, "Welcome!\n")
}

func Hello(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
	fmt.Fprintf(w, "hello, %s!\n", ps.ByName("name"))
}

func main() {
	router := httprouter.New()
	router.GET("/", Index)
	router.GET("/hello/:name", Hello)

	log.Fatal(http.ListenAndServe(":8080", router))
}

go_restful

https://github.com/joshbuddy/http_router
go get -u  github.com/julienschmidt/httprouter

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"

	"github.com/julienschmidt/httprouter"
)

type Employee struct {
	ID   string `json:"id"`
	Name string `json:"name"`
	Age  int    `json:"age"`
}

var employeeDB map[string]*Employee

func init() {
	employeeDB = map[string]*Employee{}
	employeeDB["Mike"] = &Employee{"e-1", "Mike", 35}
	employeeDB["Rose"] = &Employee{"e-2", "Rose", 45}
        employeeDB["Igo"] = &Employee{"e-3", "Igo", 25}
}

func Index(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
	fmt.Fprint(w, "Welcome!\n")
}

func GetEmployeeByName(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
	qName := ps.ByName("name")
	var (
		ok       bool
		info     *Employee
		infoJson []byte
		err      error
	)
	if info, ok = employeeDB[qName]; !ok {
		w.Write([]byte("{\"error\":\"Not Found\"}"))
		return
	}
	if infoJson, err = json.Marshal(info); err != nil {
		w.Write([]byte(fmt.Sprintf("{\"error\":,\"%s\"}", err)))
		return
	}

	w.Write(infoJson)
}

func main() {
	router := httprouter.New()
	router.GET("/", Index)
	router.GET("/employee/:name", GetEmployeeByName)

	log.Fatal(http.ListenAndServe(":8080", router))
}