一文深入解析Go语言中net/url包的URL处理机制

https://example.com:8080/path?a=1&b=2#section

type URL struct {
    Scheme     string
    Opaque     string
    User       *Userinfo
    Host       string
    Path       string
    RawQuery   string
    Fragment   string
}

package main

import (
	"fmt"
	"net/url"
)

func main() {
	// 原始URL字符串
	raw := "https://example.com:8080/path?name=go&age=10#top"
	// 解析URL字符串
	u, err := url.Parse(raw)
	if err != nil {
		panic(err)
	}

	// 输出解析结果
	fmt.Println("Scheme:", u.Scheme)
	fmt.Println("Host:", u.Host)
	fmt.Println("Path:", u.Path)
	fmt.Println("RawQuery:", u.RawQuery)
	fmt.Println("Fragment:", u.Fragment)
}

Scheme: https
Host: example.com:8080
Path: /path
RawQuery: name=go&age=10
Fragment: top

package main

import (
	"fmt"
	"net/url"
)

func main() {
	// 解析URL字符串，返回一个*url.URL类型的值
	u, _ := url.Parse("https://a.com/search?q=golang&sort=asc")
	// 获取查询参数，返回一个url.Values类型的值
	q := u.Query()
	// 通过Get方法获取指定key的value
	fmt.Println(q.Get("q"))    // golang
	fmt.Println(q.Get("sort")) // asc
}

golang
asc

package main

import (
	"fmt"
	"net/url"
)

func main() {
	// 构建一个URL对象
	u := &url.URL{
		Scheme: "https",
		Host:   "example.com",
		Path:   "/search",
	}
	// 构建查询参数
	q := url.Values{}
	// 添加查询参数
	q.Add("keyword", "go url")
	q.Add("page", "1")
	// 将查询参数编码并赋值给URL对象的RawQuery字段
	u.RawQuery = q.Encode()

	fmt.Println(u.String())
}

https://example.com/search?keyword=go+url&page=1

package main

import (
	"fmt"
	"net/url"
)

func main() {
	// 解析URL，并获取用户名和密码
	u, _ := url.Parse("https://admin:123456@example.com/dashboard")
	// 获取用户名
	fmt.Println(u.User.Username())
	// 获取密码
	fmt.Println(u.User.Password())
	// 直接获取密码
	password, _ := u.User.Password()
	fmt.Println(password)
}

admin
123456 true
123456

url := "https://example.com/search?q=" + "go url"

package main

import (
	"fmt"
	"net/url"
)

func main() {
	u, _ := url.Parse("https://example.com/search")

	q := url.Values{}
	q.Set("q", "go url")

	u.RawQuery = q.Encode()
	fmt.Println(u.String())
}

u.Path = "/search?q=go"

u.Path = "/search"
u.RawQuery = "q=go"

q := "中文参数"
u.RawQuery = "q=" + q

q := url.Values{}
q.Set("q", "中文参数")

u.RawQuery = q.Encode()

输入字符串
  ↓
识别 scheme（https://）
  ↓
解析 authority（user@host:port）
  ↓
解析 path
  ↓
解析 query（?）
  ↓
解析 fragment（#）
  ↓
填充 URL struct

type Values map[string][]string

map -> key=value&key2=value2

func ParseURL(s string):
    state = SCHEME
    for each char in s:
        switch state:
            case SCHEME:
                parse scheme
            case AUTHORITY:
                parse host/user
            case PATH:
                parse path
            case QUERY:
                parse query
            case FRAGMENT:
                parse fragment
    return URL struct