1 // main 2 package main 3  4 import ( 5     "fmt" 6     "runtime" 7     "sync" 8 ) 9 10 func main() {11     fmt.Println("Hello World!")12     runtime.GOMAXPROCS(1)13     var wg sync.WaitGroup14     wg.Add(2)15     i := 99916     fmt.Println("Start Goroutines")17 18     go func() {19         defer wg.Done()20         //共享变量 i wg21         fmt.Println(i)22         for count := 0; count < 3; count++ {23             for char := 'a'; char < 'a'+26; char++ {24                 fmt.Printf("%c ", char)25             }26         }27     }()28 29     go func() {30         defer wg.Done()31         fmt.Println(i)32         for count := 0; count < 3; count++ {33             for char := 'A'; char < 'A'+26; char++ {34                 fmt.Printf("%c ", char)35             }36         }37     }()38 39     fmt.Println("Waiting to Finish")40     wg.Wait()41 42     fmt.Println("\nTerminating Program")43 }

go 协程练习

 

 

接口练习

1 // Sample program to show what happens when the outer and inner 2 // type implement the same interface. 3 package main 4  5 import ( 6     "fmt" 7 ) 8  9 // notifier is an interface that defined notification10 // type behavior.11 type notifier interface {12     notify()13 }14 15 // user defines a user in the program.16 type user struct {17     name  string18     email string19 }20 21 // notify implements a method that can be called via22 // a value of type user.23 func (u *user) notify() {24     fmt.Printf("Sending user email to %s<%s>\n",25         u.name,26         u.email)27 }28 29 // admin represents an admin user with privileges.30 type admin struct {31     user32     level string33 }34 35 // notify implements a method that can be called via36 // a value of type Admin.37 func (a *admin) notify() {38     fmt.Printf("Sending admin email to %s<%s>\n",39         a.name,40         a.email)41 }42 43 // main is the entry point for the application.44 func main() {45     // Create an admin user.46     ad := admin{47         user: user{48             name:  "john smith",49             email: "john@yahoo.com",50         },51         level: "super",52     }53 54     // Send the admin user a notification.55     // The embedded inner type's implementation of the56     // interface is NOT "promoted" to the outer type.57     sendNotification(&ad)58 59     // We can access the inner type's method directly.60     ad.user.notify()61 62     // The inner type's method is NOT promoted.63     ad.notify()64 }65 66 // sendNotification accepts values that implement the notifier67 // interface and sends notifications.68 func sendNotification(n notifier) {69     n.notify()70 }

 

work代码注释 《go语言编程实战》

1 package work 2  3 import "sync" 4  5 //接口 6 type Worker interface { 7     Task() 8 } 9 10 //pool结构体11 type Pool struct {12     work chan Worker13     wg   sync.WaitGroup14 }15 16 //new函数  返回 pool指针17 func New(maxGorountines int) *Pool {18     p := Pool{19         work: make(chan Worker),20     }21     //wg添加wait数量22     p.wg.Add(maxGorountines)23     for i := 0; i < maxGorountines; i++ {24         go func() {25             //执行POOL内的任务 完成后wg执行done26             for w := range p.work {27                 w.Task()28             }29             p.wg.Done()30         }()31     }32 33     return &p34 }35 36 //将任务放入POOL37 func (p *Pool) Run(w Worker) {38     p.work <- w39 }40 41 //关闭POOL42 func (p *Pool) Shutdown() {43     close(p.work)44     p.wg.Wait()45 }

1 // main 2 package main 3  4 import ( 5     "fmt" 6     "log" 7     "sync" 8     "time" 9     "work"10 )11 12 var names = []string{13     "steve",14     "bob",15     "mary",16     "therese",17     "jason",18 }19 20 type namePrinter struct {21     name string22 }23 24 func (m *namePrinter) Task() {25     log.Println(m.name)26     time.Sleep(time.Second)27 }28 29 func main() {30     fmt.Println("Hello World!")31     p := work.New(2)32 33     var wg sync.WaitGroup34     wg.Add(100 * len(names))35 36     for i := 0; i < 100; i++ {37         for _, name := range names {38             np := namePrinter{39                 name: name,40             }41             go func() {42                 p.Run(&np)43                 wg.Done()44             }()45         }46     }47     wg.Wait()48     p.Shutdown()49 }

 

runner代码注释 《go语言编程实战》

1 // runner 2 package runner 3  4 import ( 5     "errors" 6     "fmt" 7     "os" 8     "os/signal" 9     "time"10 )11 12 //runner结构体13 type Runner struct {14     interrupt chan os.Signal15     complete  chan error16     timeout   <-chan time.Time17     tasks     []func(int)18 }19 20 //错误变量121 var Errtimeout = errors.New("received timeout")22 //错误变量223 var ErrInterrupt = errors.New("received interrupt")24 25 //runner的new函数26 func New(d time.Duration) *Runner {27     return &Runner{28         interrupt: make(chan os.Signal, 1),29         complete:  make(chan error),30         timeout:   time.After(d),31     }32 }33 34 //func(int)加入 runner35 func (r *Runner) Add(tasks ...func(int)) {36     r.tasks = append(r.tasks, tasks...)37 }38 39 40 //goroutine执行 结果超时或者错误 成功41 func (r *Runner) Start() error {42     signal.Notify(r.interrupt, os.Interrupt)43 44     go func() {45         r.complete <- r.run()46     }()47 48     select {49     case err := <-r.complete:50         return err51     case <-r.timeout:52         return Errtimeout53     }54 }55 56 //run函数 遍历函数数组57 //若发生错误中断则返回 中断错误58 func (r *Runner) run() error {59     for id, task := range r.tasks {60         if r.gotInterrupt() {61             return ErrInterrupt62         }63         task(id)64     }65     return nil66 }67 68 //通过interrupt接受中断69 func (r *Runner) gotInterrupt() bool {70     select {71     case <-r.interrupt:72         signal.Stop(r.interrupt)73         return true74     default:75         return false76     }77 }78 79 80 //无用main函数81 func main() {82     fmt.Println("Hello World!")83 84 }

1 // main 2 package main 3  4 import ( 5     "fmt" 6     "log" 7     "os" 8     "runner" 9     "time"10 )11 12 const timeout = 3 * time.Second13 14 func main() {15     fmt.Println("Hello World!")16     log.Println("Starting work.")17 18     r := runner.New(timeout)19 20     r.Add(createTask(), createTask(), createTask())21 22     if err := r.Start(); err != nil {23         switch err {24         case runner.Errtimeout:25             log.Println("Terminating due to timeout")26             os.Exit(1)27         case runner.ErrInterrupt:28             log.Println("Terminating due to interrupt")29             os.Exit(2)30         }31     }32     log.Println("Process ended")33 }34 35 func createTask() func(int) {36     return func(id int) {37         log.Printf("processor - Task #%d", id)38         time.Sleep(time.Duration(id) * time.Second)39     }40 }

 

go语言编程 代码修改

1 package library 2  3 //music 记录 4 type MusicEntry struct { 5     Id string 6     Name string 7     Artist string 8     Source string 9     Type string10 }

1 package library 2  3 import "errors" 4  5 //音乐管理器  音乐记录数组 6 type MusicManager struct { 7     musics []MusicEntry 8 } 9 10 //返回音乐管理器指针11 func NewMusicManager() *MusicManager {12     return &MusicManager{make([]MusicEntry, 0)}13 }14 15 //返回音乐管理器 音乐数组的元素数16 func (m *MusicManager) Len() int {17     return len(m.musics)18 }19 20 //输入索引 获取音乐记录指针21 func (m *MusicManager) Get(index int) (music *MusicEntry, err error) {22     if index < 0 || index >= len(m.musics) {23         return nil, errors.New("Index out of range.")24     }25     return &m.musics[index], nil26 }27 28 29 //根据名字字符串 查找音乐记录的指针30 func (m *MusicManager) Find(name string) *MusicEntry {31     if len(m.musics) == 0 {32         return nil33     }34 35     for _, m := range m.musics {36         if m.Name == name {37             return &m38         }39     }40     return nil41 }42 43 //添加音乐记录  输入音乐记录指针44 func (m *MusicManager) Add(music *MusicEntry) {45 46     m.musics = append(m.musics, *music)47 }48 49 50 //输入索引 移除指定索引 返回音乐记录指针51 func (m *MusicManager) Remove(index int) *MusicEntry {52     if index < 0 || index >= len(m.musics) {53         return nil54     }55 56     removedMusic := &m.musics[index]57 58     // Remove the found item from the slice.59     if index < len(m.musics)-1 { // Element between first and last60         m.musics = append(m.musics[:index-1], m.musics[index+1:]...)61     } else if index == 0 { // empty it.62         m.musics = make([]MusicEntry, 0)63     } else { // The last element64         m.musics = m.musics[:index-1]65     }66 67     return removedMusic68 }69 70 71 72 //输入名字字符串 移除符合的音乐记录  返回音乐记录指针73 func (m *MusicManager) RemoveByName(name string) *MusicEntry {74     if len(m.musics) == 0 {75         return nil76     }77 78     for i, v := range m.musics {79         if v.Name == name {80             return m.Remove(i)81         }82     }83     return nil84 }

1 package library 2  3 import "testing" 4  5 func TestOps(t *testing.T) { 6     mm := NewMusicManager() 7     if mm == nil { 8         t.Error("NewMusicManager failed") 9     }10 11     if mm.Len() != 0 {12         t.Error("NewMusicManager failed,not empty")13     }14 15     m0 := &MusicEntry{
    "1", "MyHeart", "Celion", "http://wwww", "pop"}16     mm.Add(m0)17 18     if mm.Len() != 1 {19         t.Error("MusicManager Add() failed")20     }21 22     m := mm.Find(m0.Name)23     if m == nil {24         t.Error("MusicManager Find() failed")25     }26 27     if m.Id != m0.Id || m.Name != m0.Name ||28         m.Artist != m0.Artist || m.Source != m0.Source ||29         m.Type != m0.Type {30         t.Error("MusicManager Find() failed.Found item mismatch")31     }32 33     m, err := mm.Get(0)34     if m == nil || err != nil {35         t.Error("MusicManager Get() failed")36     }37 38     m = mm.Remove(0)39     if m == nil || mm.Len() != 0 {40         t.Error("MusicManager Remove() failed")41     }42 43 }

 

服务器 代码备份

1 // main  2 package main  3   4 import (  5     //"crypto/cipher"  6     //"bufio"  7     "bytes"  8     "crypto/aes"  9     "encoding/binary" 10     "errors" 11     "fmt" 12     "log" 13     "net" 14 ) 15  16 var g_string string 17  18 type Header struct { 19     flag       byte 20     packageLen int32 21 } 22  23 //字节转换成整形 24 func BytesToInt(b []byte) int { 25     bytesBuffer := bytes.NewBuffer(b) 26  27     var x int32 28     binary.Read(bytesBuffer, binary.LittleEndian, &x) 29  30     return int(x) 31 } 32  33 func recvBuf(conn net.Conn, buf []byte) (int, error) { 34     n, err := conn.Read(buf) 35     return n, err 36 } 37  38 func recvHeader(conn net.Conn) (int, error) { 39     headerbuf := make([]byte, 5) 40     //fmt.Println("before buf:", headerbuf) 41  42     n, err := recvBuf(conn, headerbuf) 43     if err != nil || n != 5 { 44         fmt.Println("err:", err) 45         return -1, err 46     } 47     //fmt.Println("after buf:", headerbuf, "  n:", n) 48     if headerbuf[0] != '|' { 49         fmt.Println("err:flag error,exit!") 50         return -2, err 51     } 52     n = BytesToInt(headerbuf[1:]) 53     return n, err 54 } 55  56 func recvBody(conn net.Conn, n int) (int, error) { 57     var err = errors.New(" closed") 58     buf := make([]byte, n) 59  60     n, err = recvBuf(conn, buf) 61     if err != nil || n <= 0 { 62         fmt.Println("err:", err) 63         return -1, err 64     } 65     //buf 解密 66     mainecb(buf) 67  68     return n, err 69 } 70  71 func handleConn(conn net.Conn) { 72     fmt.Println("Enter func handleConn") 73     defer conn.Close() 74     who := conn.RemoteAddr().String() 75     fmt.Println(who) 76     for { 77         n, err := recvHeader(conn) 78         //fmt.Println("recvHeader n = ", n, "  ", err) 79         if n <= 0 || err != nil { 80             var ErrEOF = errors.New("EOF") 81             if err == ErrEOF { 82                 fmt.Println("err eauql") 83             } 84             fmt.Println("err:recvHeader error,exit!  ,err:", err) 85             break 86         } 87         _, err = recvBody(conn, n) 88     } 89  90 } 91  92 //=============================================== 93 //ecb 94 //=============================================== 95 //AES ECB模式的加密解密 96 type AesTool struct { 97     //128 192  256位的其中一个 长度 对应分别是 16 24  32字节长度 98     Key       []byte 99     BlockSize int100 }101 102 func (this *AesTool) Decrypt(src []byte) ([]byte, error) {103     //key只能是 16 24 32长度104     block, err := aes.NewCipher([]byte(this.Key))105     if err != nil {106         return nil, err107     }108     //返回加密结果109     decryptData := make([]byte, len(src))110     //存储每次加密的数据111     tmpData := make([]byte, this.BlockSize)112 113     //分组分块加密114     for index := 0; index < len(src); index += this.BlockSize {115         block.Decrypt(tmpData, src[index:index+this.BlockSize])116         //copy(decryptData, tmpData)117         decryptData = mergeByteArray(decryptData, tmpData)118     }119     return this.PKCS5UnPadding(decryptData), nil120 }121 122 func mergeByteArray(a []byte, b []byte) []byte {123     alen := len(a)124     blen := len(b)125 126     z := make([]byte, alen+blen)127 128     for i := 0; i < alen; i++ {129         z[i] = a[i]130     }131     for i := 0; i < blen; i++ {132         z[alen+i] = b[i]133     }134     return z135 }136 137 //unpadding138 func (this *AesTool) unPadding(src []byte) []byte {139     for i := len(src) - 1; ; i-- {140         if src[i] != 0 {141             return src[:i+1]142         }143     }144     return nil145 }146 147 func (this *AesTool) PKCS5Padding(ciphertext []byte, blockSize int) []byte {148     padding := blockSize - len(ciphertext)%blockSize149     padtext := bytes.Repeat([]byte{
    byte(padding)}, padding)150     return append(ciphertext, padtext...)151 }152 153 func (this *AesTool) PKCS5UnPadding(origData []byte) []byte {154     length := len(origData)155     // 去掉最后一个字节 unpadding 次156     unpadding := int(origData[length-1])157     origData = origData[:(length - unpadding)]158     fmt.Println("origData inner:", string(origData))159     return origData160 }161 162 func mainecb(encryptData []byte) {163     //key := []byte{'#', '2', '&', '*', '#', ....}164     blickSize := 16165     tool := NewAesTool(key, blickSize)166     decryptData, _ := tool.Decrypt(encryptData)167     fmt.Println(string(decryptData))168 }169 func NewAesTool(key []byte, blockSize int) *AesTool {170     return &AesTool{Key: key, BlockSize: blockSize}171 }172 173 //====================================================174 //var global_int = 99175 176 func main() {177     fmt.Println("Hello World!")178 179     listener, err := net.Listen("tcp", "192.。。。")180     if err != nil {181         log.Fatal(err)182     }183     for {184         conn, err := listener.Accept()185         if err != nil {186             log.Println(err)187             continue188         }189         go handleConn(conn)190     }191 192     fmt.Println("net finish...")193 }