go语言练习

 // main
 package main

 import (
     "fmt"
     "runtime"
     "sync"
 )

 func main() {
     fmt.Println("Hello World!")
     runtime.GOMAXPROCS()
     var wg sync.WaitGroup
     wg.Add()
     i :=
     fmt.Println("Start Goroutines")

     go func() {
         defer wg.Done()
         //共享变量 i wg
         fmt.Println(i)
         for count := ; count < ; count++ {
             for char := 'a'; char < 'a'+; char++ {
                 fmt.Printf("%c ", char)
             }
         }
     }()

     go func() {
         defer wg.Done()
         fmt.Println(i)
         for count := ; count < ; count++ {
             for char := 'A'; char < 'A'+; char++ {
                 fmt.Printf("%c ", char)
             }
         }
     }()

     fmt.Println("Waiting to Finish")
     wg.Wait()

     fmt.Println("\nTerminating Program")
 }

go 协程练习

接口练习

 // Sample program to show what happens when the outer and inner
 // type implement the same interface.
 package main

 import (
     "fmt"
 )

 // notifier is an interface that defined notification
 // type behavior.
 type notifier interface {
     notify()
 }

 // user defines a user in the program.
 type user struct {
     name  string
     email string
 }

 // notify implements a method that can be called via
 // a value of type user.
 func (u *user) notify() {
     fmt.Printf("Sending user email to %s<%s>\n",
         u.name,
         u.email)
 }

 // admin represents an admin user with privileges.
 type admin struct {
     user
     level string
 }

 // notify implements a method that can be called via
 // a value of type Admin.
 func (a *admin) notify() {
     fmt.Printf("Sending admin email to %s<%s>\n",
         a.name,
         a.email)
 }

 // main is the entry point for the application.
 func main() {
     // Create an admin user.
     ad := admin{
         user: user{
             name:  "john smith",
             email: "[e-mail]",
         },
         level: "super",
     }

     // Send the admin user a notification.
     // The embedded inner type's implementation of the
     // interface is NOT "promoted" to the outer type.
     sendNotification(&ad)

     // We can access the inner type's method directly.
     ad.user.notify()

     // The inner type's method is NOT promoted.
     ad.notify()
 }

 // sendNotification accepts values that implement the notifier
 // interface and sends notifications.
 func sendNotification(n notifier) {
     n.notify()
 }

work代码注释 《go语言编程实战》

 package work

 import "sync"

 //接口
 type Worker interface {
     Task()
 }

 //pool结构体
 type Pool struct {
     work chan Worker
     wg   sync.WaitGroup
 }

 //new函数  返回 pool指针
 func New(maxGorountines int) *Pool {
     p := Pool{
         work: make(chan Worker),
     }
     //wg添加wait数量
     p.wg.Add(maxGorountines)
     for i := ; i < maxGorountines; i++ {
         go func() {
             //执行POOL内的任务 完成后wg执行done
             for w := range p.work {
                 w.Task()
             }
             p.wg.Done()
         }()
     }

     return &p
 }

 //将任务放入POOL
 func (p *Pool) Run(w Worker) {
     p.work <- w
 }

 //关闭POOL
 func (p *Pool) Shutdown() {
     close(p.work)
     p.wg.Wait()
 }

 // main
 package main

 import (
     "fmt"
     "log"
     "sync"
     "time"
     "work"
 )

 var names = []string{
     "steve",
     "bob",
     "mary",
     "therese",
     "jason",
 }

 type namePrinter struct {
     name string
 }

 func (m *namePrinter) Task() {
     log.Println(m.name)
     time.Sleep(time.Second)
 }

 func main() {
     fmt.Println("Hello World!")
     p := work.New()

     var wg sync.WaitGroup
     wg.Add( * len(names))

     for i := ; i < ; i++ {
         for _, name := range names {
             np := namePrinter{
                 name: name,
             }
             go func() {
                 p.Run(&np)
                 wg.Done()
             }()
         }
     }
     wg.Wait()
     p.Shutdown()
 }

runner代码注释 《go语言编程实战》

 // runner
 package runner

 import (
     "errors"
     "fmt"
     "os"
     "os/signal"
     "time"
 )

 //runner结构体
 type Runner struct {
     interrupt chan os.Signal
     complete  chan error
     timeout   <-chan time.Time
     tasks     []func(int)
 }

 //错误变量1
 var Errtimeout = errors.New("received timeout")
 //错误变量2
 var ErrInterrupt = errors.New("received interrupt")

 //runner的new函数
 func New(d time.Duration) *Runner {
     return &Runner{
         interrupt: make(chan os.Signal, ),
         complete:  make(chan error),
         timeout:   time.After(d),
     }
 }

 //func(int)加入 runner
 func (r *Runner) Add(tasks ...func(int)) {
     r.tasks = append(r.tasks, tasks...)
 }

 //goroutine执行 结果超时或者错误 成功
 func (r *Runner) Start() error {
     signal.Notify(r.interrupt, os.Interrupt)

     go func() {
         r.complete <- r.run()
     }()

     select {
     case err := <-r.complete:
         return err
     case <-r.timeout:
         return Errtimeout
     }
 }

 //run函数 遍历函数数组
 //若发生错误中断则返回 中断错误
 func (r *Runner) run() error {
     for id, task := range r.tasks {
         if r.gotInterrupt() {
             return ErrInterrupt
         }
         task(id)
     }
     return nil
 }

 //通过interrupt接受中断
 func (r *Runner) gotInterrupt() bool {
     select {
     case <-r.interrupt:
         signal.Stop(r.interrupt)
         return true
     default:
         return false
     }
 }

 //无用main函数
 func main() {
     fmt.Println("Hello World!")

 }

 // main
 package main

 import (
     "fmt"
     "log"
     "os"
     "runner"
     "time"
 )

 const timeout =  * time.Second

 func main() {
     fmt.Println("Hello World!")
     log.Println("Starting work.")

     r := runner.New(timeout)

     r.Add(createTask(), createTask(), createTask())

     if err := r.Start(); err != nil {
         switch err {
         case runner.Errtimeout:
             log.Println("Terminating due to timeout")
             os.Exit()
         case runner.ErrInterrupt:
             log.Println("Terminating due to interrupt")
             os.Exit()
         }
     }
     log.Println("Process ended")
 }

 func createTask() func(int) {
     return func(id int) {
         log.Printf("processor - Task #%d", id)
         time.Sleep(time.Duration(id) * time.Second)
     }
 }

go语言编程 代码修改

 package library

 //music 记录
 type MusicEntry struct {
     Id string
     Name string
     Artist string
     Source string
     Type string
 }

musicentry

 package library

 import "errors"

 //音乐管理器  音乐记录数组
 type MusicManager struct {
     musics []MusicEntry
 }

 //返回音乐管理器指针
 func NewMusicManager() *MusicManager {
     return &MusicManager{make([]MusicEntry, )}
 }

 //返回音乐管理器 音乐数组的元素数
 func (m *MusicManager) Len() int {
     return len(m.musics)
 }

 //输入索引 获取音乐记录指针
 func (m *MusicManager) Get(index int) (music *MusicEntry, err error) {
     if index <  || index >= len(m.musics) {
         return nil, errors.New("Index out of range.")
     }
     return &m.musics[index], nil
 }

 //根据名字字符串 查找音乐记录的指针
 func (m *MusicManager) Find(name string) *MusicEntry {
     if len(m.musics) ==  {
         return nil
     }

     for _, m := range m.musics {
         if m.Name == name {
             return &m
         }
     }
     return nil
 }

 //添加音乐记录  输入音乐记录指针
 func (m *MusicManager) Add(music *MusicEntry) {

     m.musics = append(m.musics, *music)
 }

 //输入索引 移除指定索引 返回音乐记录指针
 func (m *MusicManager) Remove(index int) *MusicEntry {
     if index <  || index >= len(m.musics) {
         return nil
     }

     removedMusic := &m.musics[index]

     // Remove the found item from the slice.
     if index < len(m.musics)- { // Element between first and last
         m.musics = append(m.musics[:index-], m.musics[index+:]...)
     } else if index ==  { // empty it.
         m.musics = make([]MusicEntry, )
     } else { // The last element
         m.musics = m.musics[:index-]
     }

     return removedMusic
 }

 //输入名字字符串 移除符合的音乐记录  返回音乐记录指针
 func (m *MusicManager) RemoveByName(name string) *MusicEntry {
     if len(m.musics) ==  {
         return nil
     }

     for i, v := range m.musics {
         if v.Name == name {
             return m.Remove(i)
         }
     }
     return nil
 }

manager

 package library

 import "testing"

 func TestOps(t *testing.T) {
     mm := NewMusicManager()
     if mm == nil {
         t.Error("NewMusicManager failed")
     }

     if mm.Len() !=  {
         t.Error("NewMusicManager failed,not empty")
     }

     m0 := &MusicEntry{"", "MyHeart", "Celion", "http://wwww", "pop"}
     mm.Add(m0)

     if mm.Len() !=  {
         t.Error("MusicManager Add() failed")
     }

     m := mm.Find(m0.Name)
     if m == nil {
         t.Error("MusicManager Find() failed")
     }

     if m.Id != m0.Id || m.Name != m0.Name ||
         m.Artist != m0.Artist || m.Source != m0.Source ||
         m.Type != m0.Type {
         t.Error("MusicManager Find() failed.Found item mismatch")
     }

     m, err := mm.Get()
     if m == nil || err != nil {
         t.Error("MusicManager Get() failed")
     }

     m = mm.Remove()
     if m == nil || mm.Len() !=  {
         t.Error("MusicManager Remove() failed")
     }

 }

manager_test

服务器 代码备份

 // main
 package main

 import (
     //"crypto/cipher"
     //"bufio"
     "bytes"
     "crypto/aes"
     "encoding/binary"
     "errors"
     "fmt"
     "log"
     "net"
 )

 var g_string string

 type Header struct {
     flag       byte
     packageLen int32
 }

 //字节转换成整形
 func BytesToInt(b []byte) int {
     bytesBuffer := bytes.NewBuffer(b)

     var x int32
     binary.Read(bytesBuffer, binary.LittleEndian, &x)

     return int(x)
 }

 func recvBuf(conn net.Conn, buf []byte) (int, error) {
     n, err := conn.Read(buf)
     return n, err
 }

 func recvHeader(conn net.Conn) (int, error) {
     headerbuf := make([]byte, )
     //fmt.Println("before buf:", headerbuf)

     n, err := recvBuf(conn, headerbuf)
     if err != nil || n !=  {
         fmt.Println("err:", err)
         return -, err
     }
     //fmt.Println("after buf:", headerbuf, "  n:", n)
     if headerbuf[] != '|' {
         fmt.Println("err:flag error,exit!")
         return -, err
     }
     n = BytesToInt(headerbuf[:])
     return n, err
 }

 func recvBody(conn net.Conn, n int) (int, error) {
     var err = errors.New(" closed")
     buf := make([]byte, n)

     n, err = recvBuf(conn, buf)
     if err != nil || n <=  {
         fmt.Println("err:", err)
         return -, err
     }
     //buf 解密
     mainecb(buf)

     return n, err
 }

 func handleConn(conn net.Conn) {
     fmt.Println("Enter func handleConn")
     defer conn.Close()
     who := conn.RemoteAddr().String()
     fmt.Println(who)
     for {
         n, err := recvHeader(conn)
         //fmt.Println("recvHeader n = ", n, "  ", err)
         if n <=  || err != nil {
             var ErrEOF = errors.New("EOF")
             if err == ErrEOF {
                 fmt.Println("err eauql")
             }
             fmt.Println("err:recvHeader error,exit!  ,err:", err)
             break
         }
         _, err = recvBody(conn, n)
     }

 }

 //===============================================
 //ecb
 //===============================================
 //AES ECB模式的加密解密
 type AesTool struct {
     //128 192  256位的其中一个 长度 对应分别是 16 24  32字节长度
     Key       []byte
     BlockSize int
 }

 func (this *AesTool) Decrypt(src []byte) ([]byte, error) {
     //key只能是 16 24 32长度
     block, err := aes.NewCipher([]byte(this.Key))
     if err != nil {
         return nil, err
     }
     //返回加密结果
     decryptData := make([]byte, len(src))
     //存储每次加密的数据
     tmpData := make([]byte, this.BlockSize)

     //分组分块加密
     for index := ; index < len(src); index += this.BlockSize {
         block.Decrypt(tmpData, src[index:index+this.BlockSize])
         //copy(decryptData, tmpData)
         decryptData = mergeByteArray(decryptData, tmpData)
     }
     return this.PKCS5UnPadding(decryptData), nil
 }

 func mergeByteArray(a []byte, b []byte) []byte {
     alen := len(a)
     blen := len(b)

     z := make([]byte, alen+blen)

     for i := ; i < alen; i++ {
         z[i] = a[i]
     }
     for i := ; i < blen; i++ {
         z[alen+i] = b[i]
     }
     return z
 }

 //unpadding
 func (this *AesTool) unPadding(src []byte) []byte {
     for i := len(src) - ; ; i-- {
         if src[i] !=  {
             return src[:i+]
         }
     }
     return nil
 }

 func (this *AesTool) PKCS5Padding(ciphertext []byte, blockSize int) []byte {
     padding := blockSize - len(ciphertext)%blockSize
     padtext := bytes.Repeat([]byte{byte(padding)}, padding)
     return append(ciphertext, padtext...)
 }

 func (this *AesTool) PKCS5UnPadding(origData []byte) []byte {
     length := len(origData)
     // 去掉最后一个字节 unpadding 次
     unpadding := int(origData[length-])
     origData = origData[:(length - unpadding)]
     fmt.Println("origData inner:", string(origData))
     return origData
 }

 func mainecb(encryptData []byte) {
     //key := []byte{'#', '2', '&', '*', '#', ....}
     blickSize :=
     tool := NewAesTool(key, blickSize)
     decryptData, _ := tool.Decrypt(encryptData)
     fmt.Println(string(decryptData))
 }
 func NewAesTool(key []byte, blockSize int) *AesTool {
     return &AesTool{Key: key, BlockSize: blockSize}
 }

 //====================================================
 //var global_int = 99

 func main() {
     fmt.Println("Hello World!")

     listener, err := net.Listen("tcp", "192.。。。")
     if err != nil {
         log.Fatal(err)
     }
     for {
         conn, err := listener.Accept()
         if err != nil {
             log.Println(err)
             continue
         }
         go handleConn(conn)
     }

     fmt.Println("net finish...")
 }