使用go，读取指定文件，并输出到终端

• json_demo.go

• package main
  
  import (
  	"encoding/json"
  	"fmt"
  	"io/ioutil"
  	"os"
  )
  
  type v40 struct {
  	V41 int
  	V42 string
  }
  
  type jsonFile struct {
  	V1 string
  	V2 string
  	V3 string
  	v40
  }
  
  func initJsonFile() *jsonFile {
  	var jf jsonFile
  	jf.V1 = "v1"
  	jf.V2 = "v2"
  	jf.V3 = "v3"
  	jf.V41 = 41
  	jf.V42 = "v42"
  	fmt.Println(jf)
  
  	return &jf
  }
  
  func json_test() {
  
  	jf := initJsonFile()
  
  	jsons, err := json.Marshal(*jf)
  
  	if err != nil {
  		fmt.Println(err)
  	}
  
  	fmt.Println(string(jsons))
  
  	var jf2 jsonFile
  	err = json.Unmarshal(jsons, &jf2)
  
  	if err != nil {
  		fmt.Println(err)
  	}
  	fmt.Println(jf2)
  
  }
  
  func jsonReadWrite(path *string) {
  	jsonFile, err := os.Open(*path)
  	if err != nil {
  		fmt.Println(err)
  	}
  	defer jsonFile.Close()
  
  	jsonData, err := ioutil.ReadAll(jsonFile)
  	if err != nil {
  		fmt.Println(err)
  	}
  
  	fmt.Println(string(jsonData))
  
  	var jsonMap map[string]interface{}
  
  	err = json.Unmarshal(jsonData, &jsonMap)
  	if err != nil {
  		fmt.Println(err)
  	}
  	fmt.Println(jsonMap)
  	jsonMap["add"] = "add content"
  	fmt.Println(jsonMap)
  
  	jsonData, err = json.Marshal(jsonMap)
  	if err != nil {
  		fmt.Println(err)
  	}
  	err = ioutil.WriteFile("test_add.json", jsonData, 0555)
  	if err != nil {
  		fmt.Println(err)
  	}
  
  }
  

  　　

• main.go

• package main
  
  import (
  	"flag"
  	"fmt"
  )
  
  func main() {
  	json_test()
  	var path string
  	flag.StringVar(&path, "f", "", "the file path")
  	flag.Parse()
  	fmt.Println(path)
  	a := "./test.json"
  	jsonReadWrite(&a)
  }