Golang路由分发实现全解析

package main

import (
    "fmt"
    "net/http"
)

func homeHandler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "Welcome to homepage")
}

func userHandler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "User page")
}

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/", homeHandler)
    mux.HandleFunc("/user", userHandler)

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

func postHandler(w http.ResponseWriter, r *http.Request) {
    path := r.URL.Path
    if len(path) > 6 {
        id := path[6:] // 提取 /post/ 后的内容
        fmt.Fprintf(w, "Post ID: %s", id)
    } else {
        http.Error(w, "Invalid path", http.StatusBadRequest)
    }
}

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/post/", postHandler) // 注意斜杠表示前缀匹配

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

package main

import "github.com/gin-gonic/gin"

func main() {
    r := gin.Default()

    r.GET("/", func(c *gin.Context) {
        c.String(200, "Home")
    })

    r.GET("/user/:id", func(c *gin.Context) {
        id := c.Param("id")
        c.String(200, "User ID: %s", id)
    })

    r.GET("/posts/:year/:month", func(c *gin.Context) {
        year := c.Param("year")
        month := c.Param("month")
        c.String(200, "Posts from %s-%s", year, month)
    })

    r.Run(":8080")
}

type Router struct {
    handlers map[string]func(http.ResponseWriter, *http.Request)
}

func NewRouter() *Router {
    return &Router{handlers: make(map[string]func(http.ResponseWriter, *http.Request))}
}

func (r *Router) Handle(methodPath string, handler func(http.ResponseWriter, *http.Request)) {
    r.handlers[methodPath] = handler
}

func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
    key := req.Method + " " + req.URL.Path
    if handler, exists := r.handlers[key]; exists {
        handler(w, req)
    } else {
        http.Error(w, "not found", http.StatusNotFound)
    }
}

// 使用示例
func main() {
    router := NewRouter()
    router.Handle("GET /", homeHandler)
    router.Handle("GET /user", userHandler)

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