cffycls / golang

go面向对象,进阶

go

[2020.4.30 10:45] 整理2,3
[2020.3.10 10:13] 建立1

1、数据基础篇

int、string 等略。 a.切片 slice

    mSlice := make([] string,3)
    mSlice[0] = "dog"
    mSlice[1] = "cat"
    mSlice[2] = "mouse"
    mSlice = append(mSlice, "yahaha")
    //len(mSlice)、 cap(mSlice)、 copy(mIdSliceDst, mIdSliceSrc)

b.关联 map

    mMap := make(map[int] string)
    mMap[10] = "dog"
    mMap[11] = "cat"
    mMap[12] = "mouse"
    //delete(mMap,1)无有无效、 delete(mMap,11) 
    nMap := new(map[int] string)

c.结构体 struct

type Animal struct {
    Color string  //大写开头公有
}

//定义dog结构体
type Dog struct {
    Animal
    Id int
    Name string
    Age int
}
func (a *Animal)Eat() string {
    fmt.Println("Animal is Eatting")
    return "Eat yummy yummy!!"
}

d.通道 chan[nel]

    mChan := make(chan int,3) //缓存数3
    mChan <- 336
    //...
    close(mChan)

错误捕捉

func receivePanic()  {
    fmt.Print("panic + recover异常处理: ")
    defer recoverPanic()
    //panic(errors.New("I am a panic"))  //优先级最高
    //panic("I am a panic")  //优先级高
    panic(1)
}
func recoverPanic()  {
    massage := recover()
    switch massage.(type) {
    case error:
        fmt.Println("error: ", massage)
    case string:
        fmt.Println("string: ", massage)
    default:
        fmt.Println("unknown: ", massage)
    }
}

2、包定义、管理基础篇

使用版本go1.14.1.

a.go默认配置，自定义文件|包引用

GO111MODULE="on"

import (
    "main/demo_interface"
    "main/demo_struct" //current/package 

)

当前包的命名空间，起始于根目录，本目录下的文件或包的引用使用此路径。

b.其它包引用

go get github.com/go-redis/redis 

import (
    "fmt"
    "github.com/go-redis/redis/v7"
)

命令参见 go help mod

3、网络应用基础篇

a.mysql操作

    "database/sql"
    _"github.com/go-sql-driver/mysql"

type User struct {
    id                    int                   `db:"id"`
    username              string                `db:"username"`
    last_login            string                `db:"last_login"`
}
    //1、连接
    dsn := "root:123456@tcp(172.1.11.11:3306)/test?charset=utf8"
    mysqlDB, err := sql.Open("mysql", dsn)

    //2、执行SQL语句，num查询行数
    err = mysqlDB.QueryRow("select count(id) from user").Scan(&sum) 
    //3、绑定参数并执行
    stmt, err := mysqlDB.Prepare("INSERT INTO user (username,passwd,last_login) VALUES(?,?,?)")
    _, err := stmt.Exec(username, passwd, last_login) 
    rows, _ := mysqlDB.Query(`SELECT * FROM user ORDER BY id ASC`)  

    //4、处理查询结果，逐行追加到结构体
    users := []User{}
    for rows.Next() {
        err := rows.Scan(&id, &username, &passwd, &last_login)
        users = append(users, User{id, username, last_login})
        if err != nil {
            log.Fatalln(err)
        }
    }

b.redis操作

    "github.com/go-redis/redis"

    //1、连接：单机、集群
    client := redis.NewClient(&redis.Options{
        Addr:     addr,
    })
    redisCsDB = redis.NewClusterClient(&redis.ClusterOptions{
        Addrs: addr,
    })
    pong, err := redisCsDB.Ping().Result() //网络测试
    l,_ := time.LoadLocation("Asia/Shanghai")
    //2、获取数据吧
    val, err := redisCsDB.Get("set-10").Result()

c.curl

    "io/ioutil"
    "net/http"

    func curlLength (url string) string {
        //1. 建立 http.Client 客户端对象
        client := &http.Client{
            Timeout: time.Second * 10,
        }
        //2. 建立 http.Requesst 请求对象
        req, _ := http.NewRequest("GET", url, strings.NewReader("wd=?"))
        headers := map[string]string{
            "User-Agent":    "Chrome/63.0.3239.132 (Windows NT 10.0; WOW64)",
            "Authorization": "Bearer access_token",
            "Content-Type":  "application/octet-stream",
        }
        for k,v := range headers {
            req.Header.Set(k, v)
        }
        //3. 执行请求 http.Client.Do(req)，并使用ioututil.ReadAll()读取执行结果
        resp, err := client.Do(req)
        if err != nil {
            fmt.Println(err.Error())
            return err.Error()
        }
        bodyText, err := ioutil.ReadAll(resp.Body)
        if err != nil {
            fmt.Println(err.Error())
        }
    
        if resp != nil {
            if resp.StatusCode == 200 {
                return strconv.Itoa(len(string(bodyText)))
            } else {
                fmt.Println(resp.Status)
                return resp.Status
            }
        }else{
            return "0"
        }
    }