package main

import (
    "errors"
    "fmt"
    "io/ioutil"
    "reflect"
    "strings"
)

type MysqlConf struct {
    Address  string `ini:"address"`
    Port     string `ini:"port"`
    Username string `ini:"username"`
    Password string `ini:"password"`
}

type Redisconf struct {
    Host     string `ini:"host"`
    Port     string `ini:"port"`
    Password string `ini:"password"`
    Database string `ini:"database"`
}

type Conf struct {
    MysqlConf `ini:"mysql"`
    Redisconf `ini:"redis"`
}

func loadIni(fileName string, data interface{}) (err error) {

    t := reflect.TypeOf(data)
    v := reflect.ValueOf(data)
    //1 判断传进来指针 并且是结构体指针
    if t.Kind() != reflect.Ptr || t.Elem().Kind() != reflect.Struct {
        err = errors.New("input type is not Struct Ptr")
        return
    }

    //2. 读文件得到字节数据类型
    content, err := ioutil.ReadFile(fileName)
    if err != nil {
        err = errors.New("open file faild")
        return
    }

    //3. 一行一行读数据
    var sectionName string
    var structName string

    lines := strings.Split(string(content), "\n")
    for _, line := range lines {
        line = strings.TrimSpace(line)

        //3.1 空行跳过循环
        if len(line) == 0 {
            continue
        }

        //3.2 注释跳过循环
        if strings.HasPrefix(line, "#") {
            continue
        }

        //3.3 如果是 [ 开头就表示是section字段
        if strings.HasPrefix(line, "[") {
            sectionName = strings.TrimSpace(line[1 : len(line)-1])
            for i := 0; i < v.Elem().NumField(); i++ {
                field := v.Elem().Type().Field(i)
                if sectionName == field.Tag.Get("ini") {
                    structName = field.Name
                }
            }
        } else {
            // 获取seciton下面的key and value
            key := strings.TrimSpace(strings.Split(line, "=")[0])
            value := strings.TrimSpace(strings.Split(line, "=")[1])

            // 获取嵌套里的struct
            structObj := v.Elem().FieldByName(structName)

            // 获取最终的字段
            var fieldName string
            for i := 0; i < structObj.NumField(); i++ {
                field := structObj.Type().Field(i)
                if key == field.Tag.Get("ini") {
                    fieldName = field.Name
                }
            }

            //赋值操作
            structObj.FieldByName(fieldName).SetString(value)
        }

    }

    return nil
}

func main() {
    var cfg Conf
    err := loadIni("./conf.ini", &cfg)
    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Printf("Mysql address is:%s\n", cfg.MysqlConf.Address)
    fmt.Printf("Mysql port is:%s\n", cfg.MysqlConf.Port)
    fmt.Printf("Mysql username is:%s\n", cfg.MysqlConf.Username)
    fmt.Printf("Mysql password is:%s\n", cfg.MysqlConf.Password)

    fmt.Printf("Redis host is:%s\n", cfg.Redisconf.Host)
    fmt.Printf("Redis port is:%s\n", cfg.Redisconf.Port)
    fmt.Printf("Redis password is:%s\n", cfg.Redisconf.Password)
    fmt.Printf("Redis database is:%s\n", cfg.Redisconf.Database)
}

conf.ini

[mysql]
address=192.168.100.100
port=3306
username=root
password=BaVzJJJlNBS47uo9KduonCtMrdPhyYVG



[redis]
host= 127.0.0.1
port= 6379
password=123.com
database=0