2.4 面向對象編程

2.4.1匿名組合

type Person struct {id intname stringage int }type Student struct {Person //只有類型 沒有名字,匿名字段 繼承了person的成員garde stringclass string }

2.4.1.2 定義類,賦值,修改

//定義類var per1 Student = Student{Person{1, "生活", 18}, "初中", "初一"}fmt.Println("per1", per1)//自動推導類型per2 := Student{Person{1, "生活", 18}, "初中", "初一"}fmt.Printf("per2 %v\n", per2)//單獨復制per3 := Student{class: "初一"}fmt.Printf("per3 %v\n", per3)per4 := Student{Person: Person{id: 5}, class: "初一"}per4.name = "sss"per4.Person = Person{5, "aaa", 22}fmt.Printf("per4 %v\n", per4)

2.4.1.3 匿名字段追加

//非結構匿名字段 type addColum string func main() {per2 := Student{Person{1, "生活", 18}, "初中", "初一", "追加字段"}fmt.Printf("per2 %v\n", per2)//per2 {{1 生活 18} 初中 初一 追加字段} }

2.4.1.4 地址匿名字段追加

//非結構匿名字段 type addColum stringtype Person struct {id intname stringage int }type Student struct {*Person //只有類型 沒有名字,匿名字段 繼承了person的成員garde stringclass stringaddColum }func main() {per2 := Student{&Person{1, "生活", 18}, "初中", "初一", "追加字段"}fmt.Printf("per2 %v\n", per2)fmt.Println(per2.id, per2.name, per2.age, per2.garde, per2.class)var per3 Studentper3.Person = new(Person)per3.addColum = "append"per3.id = 5per3.name = "sss"fmt.Println(per3.id, per3.name, per3.age, per3.garde, per3.class) }

2.4.2方法

2.4.2.1 定義

//面向對象,方法:給某個類型綁定一個函數 type long int//tmp叫接受者,接受者傳遞的一個參數 func (tmp long) Add02(other long) long {fmt.Println("tmp =", tmp)//1return tmp + other}func main() {//定義一個變量var test long = 1//調用方法格式 :變量名.函數r := test.Add02(3)fmt.Println("r =", r)//4}

2.4.2.2 賦值,輸出

//輸出函數 func (per Person) pringInfo() {fmt.Println("per =", per) }//賦值函數 func (per Person) setInfo(a int, b string, c int) {per.id = aper.name = bper.age = cfmt.Println("per =", per) }func main() {per1 := Person{1, "小三", 20}per1.pringInfo()per1.setInfo(2, "小三的小三", 21)}

2.4.2.3 值傳遞與引用傳遞

type Person struct {id intname stringage int }//賦值函數 func (per Person) setInfo(a int, b string, c int) {per.id = aper.name = bper.age = cfmt.Printf("per = %v\n", per)//per = {3 修改 22} }//引用傳遞 func (per *Person) setInfoPoint(a int, b string, c int) {per.id = aper.name = bper.age = cfmt.Printf("per = %v\n", per)//per = &{4 修改 32} }func main() {per1 := Person{1, "小三", 20}per1.setInfo(3, "修改", 22) //引用傳遞fmt.Println(per1)//{1 小三 20}per2 := Person{2, "小三的小三", 21}per2.setInfoPoint(4, "修改", 32) //值傳遞fmt.Println(per2) //{4 修改 32}}

2.4.2.4 繼承傳遞

type Person struct {id intname stringage int }type Student struct {Persongarde string } //輸出函數 func (per Person) pringInfo() {fmt.Println("per =", per) }func main() {//繼承stu := Student{Person{5, "小三5", 25}, "s"}stu.pringInfo()fmt.Println(stu)}

2.4.2.5 方法值

stu := Student{Person{5, "小三5", 25}, "s"}stu.pringInfo()//方法值 保存方式入口地址pFunc := stu.pringInfo //這個就是方法值,調用函數時,無需再傳遞接受者pFunc() //等價于 stu.pringInfo()

2.4.2.5 方法表達式

//方法表達式f := (*PePerson).setInfoPointf(&stu) //等價于 stu.setInfoPoint()f1 := (PePerson).setInfof1(stu) //等價于 stu.setInfo()fmt.Println(stu)

2.4.3接口

2.4.3.1 定義

//定義接口 type inter interface {say() }//studnt實現了say方法 func (tmp *Teacher) say() {fmt.Printf("Studnt %s\n", tmp.zz) }func main() {var i inter//只要實現 該接口,就可以給這個接口賦值s := &Teacher{"是啥"}i = si.say()//Studnt 是啥 }

2.4.3.2 繼承實現

type inter interface {say() } type inter1 interface {intersay1() }//studnt實現了say方法 func (tmp *Teacher) say() {fmt.Printf("Studnt %s\n", tmp.zz) }//studnt實現了say1方法 func (tmp *Teacher) say1() {fmt.Printf("Studnt %s\n", tmp.zz) }func main() {var i inter1//只要實現 該接口,就可以給這個接口賦值s := &Teacher{"是啥"}i = si.say()i.say1() }

2.4.3.3 接口轉換

var i1 inter1 //超集i1 = &Teacher{"是啥"}var i inter //子集i = i1 //可以 超集可以轉換為子集i.say()

2.4.3.4 空接口

i := make([]interface{}, 3)i[0] = 1i[1] = "ss"for index, data := range i {if value, ok := data.(int); ok == true {fmt.Printf("index [%v] ,x[%d]\n", index, value)}}

2.5 異常處理,字符串

2.5.1錯誤接口(error)

err1 := fmt.Errorf("%s", "no error")fmt.Println(err1)err2 := errors.New("錯誤")fmt.Println(err2)

2.5.1.1錯誤接口的應用

func MyDiv(a, b int) (result int, err error) {err = nilif b == 0 {err = errors.New("B不能為0")} else {result = a / b}return}func main() {val, err := MyDiv(1, 0)if err != nil {fmt.Println(err)} else {fmt.Println(val)}}

2.5.2函數程序中斷(panic)

func test() {//導致程序中斷panic("this is a panic") }

2.5.3函數程序(recover)

func test1() {defer func() {//err是該函數默認返回值if err := recover(); err != nil {fmt.Println(err)}}() //()調用此函數 }

2.5.4字符串函數的使用

fmt.Println(strings.Contains("abcdefg", "abc")) //truearr := []string{"abc", "hello", "arr"}fmt.Println(strings.Join(arr, "@")) //abc@hello@arrfmt.Println(strings.Index("abcdefg", "b")) //1arrStr := "abc@hello@arr"fmt.Println(strings.Split(arrStr, "@")) //[abc hello arr]

2.5.5 strconv包

arr1 := make([]byte, 0, 1024)arr1 = strconv.AppendBool(arr1, true)//整數轉字符串arr2 := strconv.Itoa(6666)fmt.Println(arr2)//其他類型轉換為字符串var str stringstr = strconv.FormatBool(false)fmt.Println(str)

2.6 json

2.6.1 結構體轉json

import "fmt" import "encoding/json"//首字母必須大寫 type Student struct {Id int `json:"-"` //此字段不會輸出Name string `json:"name"` //返回時返回指定字段Sub []stringIsOk bool `json:",string"` //返回字符串Price float64 }func main() {stu := Student{1, "小明", []string{"go", "java", "php"}, true, 50.00}fmt.Println(stu)//json轉義buf, err := json.Marshal(stu)if err != nil {fmt.Println(err)return}fmt.Println(buf) //[123 34 73 100 34 58 49 44 34 78 97 109 101 34 58 34 229 176 143 230 152 142 34 44 34 83 117 98 34 58 91 34 103 111 34 44 34 106 97 118 97 34 44 34 112 104 112 34 93 44 34 73 115 79 107 34 58 116 114 117 101 44 34 80 114 105 99 101 34 58 53 48 125]fmt.Println(string(buf)) }

2.6.2 map轉json

map1 := make(map[string]interface{}, 4)map1["id"] = 5map1["name"] = "實時"buf, err := json.MarshalIndent(map1, "", " ")fmt.Println(string(buf))fmt.Println(err)

2.6.3 json轉實體

func main() {jsonBuf := `{"id": 5,"name": "實時"}`var stu1 Studentjson.Unmarshal([]byte(jsonBuf), &stu1)fmt.Println(stu1)//{0 實時 [] false 0}}

2.6.4 json轉map

func main() {jsonBuf := `{"id": 5,"name": "實時"}`map2 := make(map[string]interface{}, 4)json.Unmarshal([]byte(jsonBuf), &map2)fmt.Println(map2)//斷言 判斷類型var str stringfor key, value := range map2 {switch data := value.(type) {case string:str = datafmt.Printf("map[%s]的值類型為string", key)case []interface{}:fmt.Printf("map[%s]interface{}", key)}}}

2.7 goroutine并發并行

2.7.1 demo

import "fmt" import "time"func newWork() {for {fmt.Println("this is newWork")time.Sleep(1000)} }func main() {//設置并行處理器num := runtime.GOMAXPROCS(1)fmt.Println(num)//goroutinego newWork() //新建一個協程任務for {fmt.Println("this is mainWork")time.Sleep(1000)} }

2.7.2主協程退出,子協程也退出

func main() {//主協程退出了,其它子協程也要跟著退出go func() {for {fmt.Println("this is goroutine")}}()i := 0for {i++fmt.Println("this is mainFor")time.Sleep(1000)if i > 2 {break}}}

2.7.3 Goschedr讓出調度資源 Goexit 終止

import "runtime" func main() {//設置并行處理器num := runtime.GOMAXPROCS(1)fmt.Println(num)//Goschedrgo func() {for j := 0; j < 2; j++ {fmt.Println("this is goroutine")runtime.Goexit() //終止所有協程}}()i := 0for {i++fmt.Println("this is mainFor")runtime.Gosched() //讓出時間片,先讓其他協議執行if i > 2 {break}}}

2.7.4

2.7.4.1 Demo channel管道

//創建一個無緩存的channel var ch = make(chan int)func printWork(val string) {fmt.Println(val)fmt.Println(val)fmt.Println(val)fmt.Println(val)fmt.Println(val)}func per(sendv string) {printWork(sendv)ch <- 666 //給管道協數據,發送 }func per1(sendv string) {<-ch //從管道取數據,接收,如果管道沒有數據阻塞printWork(sendv) }func main() {go per("per1")go per("per2")for {}// per2// per2// per2// per2// per1// per1// per1 }

2.7.4.2 channel 特點

func main() { var ch3 chan<- float64 //ch3是單向channel 只用于讀寫float64數據 ch := make(chan int)//雙向隱轉單向var writhCh chan<- int = ch //只能寫,不能讀var readCh <-chan int = ch //只能讀,不能寫writh <-666 //寫<-readch//讀//單向無法轉換為雙向var ch2 chan int = writhCh}

2.7.4.3 channel 應用

//生產者 只能寫,不能讀 func product(out chan<- int) {for i := 0; i < 10; i++ {out <- i * i}close(out)}//消費者 只能讀,不能寫 func consumer(in <-chan int) {for num := range in {fmt.Println("consumer=", num)}}func main() {//創建一個雙向通道ch := make(chan int)//生產者go product(ch)//消費者consumer(ch)}

2.7.4.4 定時器

import "time"func main() {//只執行一次timer := time.NewTimer(2 * time.Second)//重復執行timer1 :=time.NewTicker(2 * time.Second)fmt.Println(time.Now())t := <-timer.Cfmt.Println(t)timer.Reset(1 * time.Second) //重新設置timer.Stop() //定時器停止//2020-06-13 14:06:05.8875131 +0800 CST m=+0.008002001//2020-06-13 14:06:07.8881753 +0800 CST m=+2.008664201 }

2.7.4.5 select用法

func main() {ch := make(chan int)quit := make(chan bool)//新開一個協程//讀數據go func() {for {select {case num := <-ch:fmt.Println("num = ", num)case <-time.After(3 * time.Second):fmt.Println("超時")quit <- true}}}() //自調用//寫數據for i := 0; i < 5; i++ {ch <- itime.Sleep(time.Second)}<-quitfmt.Println("程序結束")}

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