Go语言七篇入门教程五文件及包

目录

• 1. 文件处理

• 1.1 JSON文件

• 1.1.1 已知JSON结构
• 1.1.2 未知JSON结构
• 1.1.3 Encoder & Decoder

• 1.4.1 创建zip
• 1.4.2 读取zip文件

• 2.1 包路径

func Marshal(v interface{}) ([]byte, error) 	  // 生成 JSON
func Unmarshal(data []byte, v interface{}) error  // 解析 JSON 到 struct

package main
import (
	"encoding/json"
	"fmt"
)
type Person struct {
	Name string
	Age   string
}
type PersonSlice struct {
	Persons []Person
}
func main() {
	var s PersonSlice
	str := `{"persons":[{"Name":"FanOne","Age":"17"},{"Name":"FanOne2","Age":"18"},{"Name":"FanOne3","Age":"19"}]}`
	_ = json.Unmarshal([]byte(str), &s) 
	// Golang中提供软件包"encoding/json"可以直接用来处理JSON文件，此包中解析JSON的函数为Unmarshal
	// 使用此函数可以将JSON文件解析到结构体中
	fmt.Println(s.Persons)//[{FanOne 17} {FanOne2 18} {FanOne3 19}]
	for _,item:=range s.Persons{
		fmt.Println("Name",item.Name,"Age",item.Age)
		//Name FanOne Age 17
		//Name FanOne2 Age 18
		//Name FanOne3 Age 19
	}
}

b := []byte(`{
		"Name": "FanOne",
		"School": ["FZU", "XCZX", "UUUU", "GuaguaSong", "HanTuo",
		"City", "FuZhou"],
		"Major": "BigData",
		"IsPublished": true,
		"Price": 9.99,
		"Sales": 1000000
}`)
var r interface{}
err := json.Unmarshal(b, &r)

	map[string]interface{}{ 
		"Name": "FanOne",
		"School": ["FZU", "XCZX", "UUUU", "GuaguaSong", "HanTuo",
		"City", "FuZhou"],
		"Major": "BigData",
		"IsPublished": true,
		"Price": 9.99,
		"Sales": 1000000
	}

	if ok {
		for k, v := range gobook
		{
			switch v2 := v.(type)
			{
			case string:
				fmt.Println(k, "is string", v2)
			case int:
				fmt.Println(k, "is int", v2)
			case bool:
				fmt.Println(k, "is bool", v2)
			case []interface{}:
				fmt.Println(k, "is an array:")
				for i, iv := range v2 {
					fmt.Println(i, iv)
				}
			default:
				fmt.Println(k, "is another type not handle yet")
			}
		}
	}

func NewDecoder(r io.Reader) *Decoder
func NewEncoder(w io.Writer) *Encoder

func main() {
	dec := json.NewDecoder(os.Stdin)
	enc := json.NewEncoder(os.Stdout)
	for {
		var v map[string]interface{}
		if err := dec.Decode(&v); err != nil{
			log.Println(err)
			return
		}
		for k := range v {
			if k != "Name" {
				v[k] = nil,false
			}
		}
		if err := enc.Encode(&v); err != nil{
			log.Println(err)
		}
	}
}

<Person>
    <FirstName>Fan</FirstName>
    <LastName>One</LastName>
</Person>

复制代码
// xml.go
package main
import (
    "encoding/xml"
    "fmt"
    "strings"
)
var t, token xml.Token
var err error
func main() {
    input := "<Person><FirstName>Fan</FirstName><LastName>One</LastName></Person>"
    inputReader := strings.NewReader(input)
    p := xml.NewDecoder(inputReader)
    for t, err = p.Token(); err == nil; t, err = p.Token() {
        switch token := t.(type) {
        case xml.StartElement:
            name := token.Name.Local
            fmt.Printf("Token name: %s\n", name)
            for _, attr := range token.Attr {
                attrName := attr.Name.Local
                attrValue := attr.Value
                fmt.Printf("An attribute is: %s %s\n", attrName, attrValue)
            }
        case xml.EndElement:
            fmt.Println("End of token")
        case xml.CharData:
            content := string([]byte(token))
            fmt.Printf("This is the content: %v\n", content)
            // ...
        default:
            // ...
        }
    }
}

Token name: Person
Token name: FirstName
This is the content: Fan
End of token
Token name: LastName
This is the content: One
End of token
End of token

set CGO_ENABLED=0
set GOOS=linux
set GOARCH=amd64
go build main.go

func createZip(filename string) {
	// 缓存压缩文件内容
	buf := new(bytes.Buffer)
	// 创建zip
	writer := zip.NewWriter(buf)
	defer writer.Close()
	// 读取文件内容
	content, _ := ioutil.ReadFile(filepath.Clean(filename))
	// 接收
	f, _ := writer.Create(filename)
	f.Write(content)
	filename = strings.TrimSuffix(filename, path.Ext(filename)) + ".zip"
	ioutil.WriteFile(filename, buf.Bytes(), 0644)
}

func readZip(filename string) {
      zipFile, err := zip.OpenReader(filename)  // 打开zip文件
		if err != nil {
			panic(err.Error())
		}
		defer zipFile.Close()
		for _, f := range zipFile.File {  // 循环读取zip中的内容
			info := f.FileInfo()
			if info.IsDir() { 
				err = os.MkdirAll(f.Name, os.ModePerm)
				if err != nil {
					panic(err.Error())
				}
				continue
			}
			srcFile, err := f.Open()  // 打开文件
			if err != nil {
				panic(err.Error())
			}
			defer srcFile.Close()
			newFile, err := os.Create(f.Name)
			if err != nil {
				panic(err.Error())
			}
			defer newFile.Close()
			io.Copy(newFile, srcFile)
		}
}