golang json 格式文件解析

package main
import (
	"bytes"
	"encoding/json"
	"fmt"
	"log"
	"os"
	"regexp"
	"time"
)
const configFileSizeLimit = 10 << 20
var defaultConfig = &struct {
	netTimeout  int64
	fileDeadtime string
}{
	netTimeout:  15,
	fileDeadtime: "24h",
}
//有了`json:network`这种注释,后面json解析就可以把相应的数据塞到对应的结构里面来
type Config struct {
	Network NetworkConfig `json:network`
	Files  []FileConfig `json:files`
}
type NetworkConfig struct {
	Servers    []string `json:servers`
	SSLCertificate string  `json:"ssl certificate"`
	SSLKey     string  `json:"ssl key"`
	SSLCA     string  `json:"ssl ca"`
	Timeout    int64  `json:timeout`
	timeout    time.Duration
}
type FileConfig struct {
	Paths  []string     `json:paths`
	Fields  map[string]string `json:fields`
	DeadTime string      `json:"dead time"`
	deadtime time.Duration
}
func main() {
	LoadConfig("E:/golang/src/github.com/test/logstast_forwarder.conf")
}
func LoadConfig(path string) (config Config, err error) {
	config_file, err := os.Open(path)
	if err != nil {
		emit("Failed to open config file '%s': %s\n", path, err)
		return
	}
	fi, _ := config_file.Stat()
	if size := fi.Size(); size > (configFileSizeLimit) {
		emit("config file (%q) size exceeds reasonable limit (%d) - aborting", path, size)
		return // REVU: shouldn't this return an error, then?
	}
	if fi.Size() == 0 {
		emit("config file (%q) is empty, skipping", path)
		return
	}
	buffer := make([]byte, fi.Size())
	_, err = config_file.Read(buffer)
	emit("\n %s\n", buffer)
	buffer, err = StripComments(buffer) //去掉注释
	if err != nil {
		emit("Failed to strip comments from json: %s\n", err)
		return
	}
	buffer = []byte(os.ExpandEnv(string(buffer))) //特殊
	err = json.Unmarshal(buffer, &config) //解析json格式数据
	if err != nil {
		emit("Failed unmarshalling json: %s\n", err)
		return
	}
    fmt.Printf("111111111 %s \n", config.Network.Servers)
	for k, _ := range config.Files {
		if config.Files[k].DeadTime == "" {
			config.Files[k].DeadTime = defaultConfig.fileDeadtime
		}
		config.Files[k].deadtime, err = time.ParseDuration(config.Files[k].DeadTime)
		if err != nil {
			emit("Failed to parse dead time duration '%s'. Error was: %s\n", config.Files[k].DeadTime, err)
			return
		}
	}
	return
}
func StripComments(data []byte) ([]byte, error) {
	data = bytes.Replace(data, []byte("\r"), []byte(""), 0) // Windows
	lines := bytes.Split(data, []byte("\n"))        //split to muli lines
	filtered := make([][]byte, 0)
	for _, line := range lines {
		match, err := regexp.Match(`^\s*#`, line)
		if err != nil {
			return nil, err
		}
		if !match {
			filtered = append(filtered, line)
		}
	}
	return bytes.Join(filtered, []byte("\n")), nil
}
func emit(msgfmt string, args ...interface{}) {
	log.Printf(msgfmt, args...)
}

json配置文件:

## json format file
{
 "network": {
  "servers": [ "localhost:5043" ]
 },
 "files": [
  {
  "paths": [""]
  
  }
 ]
}

输出结果:

111111111 [localhost:5043] 
	
	2015年10月05日 16:45:21 
	 ## json format file
	{
	 "network": {
	  "servers": [ "localhost:5043" ]
	 },
	 "files": [
	  {
	  "paths": [""]
	  
	  }
	 ]
	}

可见,golang对json文件的解析非常简单和舒服

本文来自:开源中国博客

感谢作者:webyh

查看原文:golang json 格式文件解析

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