【Go学习笔记】 string转Map 和 Map嵌套取值 和 interface转string

Go字符串转Map 和 Map的嵌套取值

想用Go写爬虫练习一下语法的，结果数据类型转换还不熟悉。
强行 map嵌套取值就会报错type interface {} does not support indexing

字符串转Map

// 示例字符串
resString := `
{
	"args": {}, 
	"headers": {
		"Accept-Encoding": "gzip", 
		"Host": "httpbin.org", 
		"User-Agent": "GRequests/0.10", 
		"X-Amzn-Trace-Id": "Root=1-5f3f3xxxxxxccdc4068"
	}, 
	"origin": "11.11.11.22", 
	"url": "http://httpbin.org/get"
	}
	`
func StringToMap(content string)  map[string]interface{}{
	var resMap map[string]interface{}
	err := json.Unmarshal([]byte(content), &resMap)
	if err != nil {
		fmt.Println("string转map失败", err)
	}
	return resMap
}

resMap := StringToMap(resString)
fmt.Println("url取值", resMap["url"], reflect.TypeOf(resMap["url"]))

其中resMap["url"]是一个insterface类型，如下转成string

resMap["url"].(string)

Map嵌套取值

接着上面的例子，比如要取headers里面的Host值
如果是直接

resMap["headers"]["Host"]

就会报错 type interface {} does not support indexing

// 内部嵌套的map 也要转换
innerMap := resMap["headers"].(map[string]interface{})

fmt.Println("Host取值", innerMap["Host"], reflect.TypeOf(innerMap["Host"]))

我使用了Go二次封装的http库 grequests https://github.com/levigross/grequests

对目标网址发送请求，返回一个json类型字符串。
目标网址Get请求: http://httpbin.org/get
会得到一个Json字符串

{
    "args": {},
    "headers": {
        "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9",
        "Accept-Encoding": "gzip, deflate",
        "Accept-Language": "zh-CN,zh;q=0.9",
        "Host": "httpbin.org",
        "Upgrade-Insecure-Requests": "1",
        "User-Agent": "Mozilla/5.0 (Macintosh; xx) Appit/537.3xxxxx6 (KxxxxHTML, like Gecko) Chrome/84.0.414xxx25 xxxxx37.36",
        "X-Amzn-Trace-Id": "Root=1-5f3f3bae-cxxxxxxdb4121b44de07769"
    },
    "origin": "111.111.111.111",
    "url": "http://httpbin.org/get"
}

完整代码

package main

import (
	"encoding/json"
	"fmt"
	"github.com/levigross/grequests"
	"reflect"
)

func main() {
	//You can modify the request by passing an optional RequestOptions struc
	//resp, err := grequests.Get("http://httpbin.org/get", nil)
	//
	//if err != nil {
	//	fmt.Println("Unable to make request: ", err)
	//}
	//resString := resp.String()
	//
	//fmt.Println(resString)
	resString := `
			{
			  "args": {}, 
			  "headers": {
				"Accept-Encoding": "gzip", 
				"Host": "httpbin.org", 
				"User-Agent": "GRequests/0.10", 
				"X-Amzn-Trace-Id": "Root=1-5f3f3e21-44e7f0e4cec2d98cccdc4068"
			  }, 
			  "origin": "116.233.234.60", 
			  "url": "http://httpbin.org/get"
			}
	`
	var resMap map[string]interface{}

	err := json.Unmarshal([]byte(resString), &resMap)

	if err != nil {
		fmt.Println("string转map失败", err)
	}
	
	// go type interface {} does not support indexing
	fmt.Println("args取值", resMap["args"], reflect.TypeOf(resMap["args"]))
	fmt.Println("origin取值", resMap["origin"], reflect.TypeOf(resMap["origin"]))
	
	// 内部嵌套的map 也要转换
	innerMap := resMap["headers"].(map[string]interface{})

	fmt.Println("Host取值", innerMap["Host"], reflect.TypeOf(innerMap["Host"]))
	
}

输出

args取值 map[] map[string]interface {}
origin取值 116.233.234.60 string
Host取值 httpbin.org string

还有个二次封装的请求库，看起来也不错

github.com/imroc/req

总结

Go 这些数据类型操作，还是有些繁琐，相对比Python这些操作，就显得很简洁了。