第1章 初识Go语言
1.1 语言特性
1.2 安装和设置
1.3 工程构造
1.3.1 工作区
1.3.2 GOPATH
1.3.3 源码文件
package main
import (
"fmt"
"runtime"
)
:::"C"}
var info string
func init() {
fmt.Printf("Init :: Map: %v\n",m)
info = fmt.Sprintf("OS: %s,Arch: %s",runtime.GOOS,runtime.GOARCH)
}
func main() {
fmt.Printf("main :: %s",info)
}
pkg_init
1.3.4 代码包
1.4 标准命令简述
1.5 问候程序
package main
import (
"bufio"
"os"
"fmt"
)
func main() {
inputReader := bufio.NewReader(os.Stdin)
fmt.Println("Please input your name:")
input,err := inputReader.ReadString('\n')
if err != nil {
fmt.Printf("Found an error : %s\n",err)
} else {
input = input[:len(input)-]
fmt.Printf("Hello,%s!\n",input)
}
}
hello
1.6 小结
第2章 语法概述
2.1 基本构成要素
2.1.1 标识符
2.1.2 关键字
2.1.3 字面量
2.1.4 操作符
2.1.5 表达式
2.2 基本类型
2.3 高级类型
2.3.1 数组
2.3.2 切片
2.3.3 字典
2.3.4 函数和方法
2.3.5 接口
2.3.6 结构体
2.4 流程控制
2.4.1 代码块和作用域
package main
import "fmt"
var v = "1,2,3"
func main() {
v := [],,}
if v != nil {
fmt.Printf("%v\n",v)
}
}
redeclare
2.4.2 if语句
2.4.3 switch语句
2.4.4 for语句
2.4.5 defer语句
2.4.6 panic和recover
2.5 聊天机器人
package main
import (
"bufio"
"os"
"fmt"
"strings"
)
func main() {
inputReader := bufio.NewReader(os.Stdin)
fmt.Println("Please input your name:")
input,err := inputReader.ReadString('\n')
if err != nil {
fmt.Printf("An error occurred: %s\n",err)
os.Exit()
} else {
name := input[:len(input)-]
fmt.Printf("Hello, %s! What can I do for you?\n",name)
}
for {
input,err = inputReader.ReadString('\n')
if err != nil {
fmt.Printf("An error occurred: %s\n",err)
continue
}
input = input[:len(input)-]
input = strings.ToLower(input)
switch input {
case "":
continue
case "nothing","bye":
fmt.Println("Bye!")
os.Exit()
default:
fmt.Println("Sorry,I didn't catch you.")
}
}
}
simple
2.6 小结
第3章 并发编程综述
3.1 并发编程基础
3.1.1 串行程序与并发程序
3.1.2 并发程序与并行程序
3.1.3 并发程序与并发系统
3.1.4 并发程序的不确定性
3.1.5 并发程序内部的交互
3.2 多进程编程
3.2.1 进程
3.2.2 关于同步
3.2.3 管道
3.2.4 信号
3.2.5 socket
3.3 多线程编程
3.3.1 线程
3.3.2 线程的同步
3.4 多线程与多进程
3.5 多核时代的并发编程
3.6 小结
第4章 Go的并发机制
4.1 原理探究
4.1.1 线程实现模型
4.1.2 调度器
4.1.3 更多细节
4.2 goroutine
4.2.1 go语句与goroutine
package main
func main() {
go println("Go!Goroutine!")
}
gobase1
package main
import "time"
func main() {
go println("Go! Goroutine!")
time.Sleep(time.Millisecond)
}
gobase2
package main
import (
"fmt"
"time"
)
func main() {
name := "Eric"
go func() {
fmt.Printf("Hello,%s!\n",name)
}()
name = "Harry"
time.Sleep(time.Millisecond)
}
gobase3
package main
import (
"fmt"
"time"
)
func main() {
names := []string{"Eric","Harry","Robert","Jim","Mark"}
for _,name := range names {
go func() {
fmt.Printf("Hello,%s\n",name)
}()
}
time.Sleep(time.Millisecond)
}
gobase4
package main
import (
"fmt"
"time"
)
func main() {
names := []string{"Eric","Harry","Robert","Jim","Mark"}
for _,name := range names {
go func(who string) {
fmt.Printf("Hello,%s\n",who)
}(name)
}
time.Sleep(time.Millisecond)
}
gobase5
4.2.2 主goroutine的运作
4.2.3 runtime包与goroutine
4.3 channel
4.3.1 channel的基本概念
package main
import (
"fmt"
"time"
)
)
func main() {
syncChan1 := make(chan )
syncChan2 := make(chan )
go func() {
<-syncChan1
fmt.Println("Received a sync signal and wait a second... [receiver]")
time.Sleep(time.Second)
for {
if elem,ok := <- strChan;ok {
fmt.Println("Received:",elem,"[receiver]")
} else {
break
}
}
fmt.Println("Stopped. [receiver]")
syncChan2 <- struct{}{}
}()
go func() {
for _,elem := range []string{"a","b","c","d"} {
strChan <- elem
fmt.Println("Sent:",elem,"[sender]")
if elem == "c" {
syncChan1 <- struct{}{}
fmt.Println("Sent a sync signal. [Sender]")
}
}
fmt.Println("Wait 2 seconds... [sender]")
time.Sleep(time.Second * )
close(strChan)
syncChan2 <- struct{}{}
}()
<-syncChan2
<-syncChan2
}
chanbase1
package main
import (
"fmt"
"time"
)
)
func main() {
syncChan := make(chan )
go func() {
for {
if elem,ok := <- mapChan;ok {
elem["count"]++
} else {
break
}
}
fmt.Println("Stopped. [receiver]")
syncChan <- struct{}{}
}()
go func() {
countMap := make(map[string]int)
; i < ; i++ {
mapChan <- countMap
time.Sleep(time.Millisecond)
fmt.Printf("The count map: %v. [sender]\n",countMap)
}
close(mapChan)
syncChan <- struct{}{}
}()
<-syncChan
<-syncChan
}
chanval1
package main
import (
"fmt"
"time"
)
type Counter struct {
count int
}
)
func main() {
syncChan := make(chan )
go func() {
for {
if elem,ok := <- mapChan;ok {
counter := elem["count"]
counter.count++
} else {
break
}
}
fmt.Println("Stopped. [receiver]")
syncChan <- struct{}{}
}()
go func() {
countMap := map[string]Counter {
"count": Counter{},
}
; i < ; i++ {
mapChan <- countMap
time.Sleep(time.Millisecond)
fmt.Printf("The count map: %v. [sender]\n",countMap)
}
close(mapChan)
syncChan <- struct{}{}
}()
<- syncChan
<- syncChan
}
chanval2
package main
import "fmt"
func main() {
dataChan := make(chan )
syncChan1 := make(chan )
syncChan2 := make(chan )
go func() {
<- syncChan1
for {
if elem,ok := <- dataChan;ok {
fmt.Println("Received: %d [receiver]\n",elem)
} else {
break
}
}
fmt.Println("Done. [receiver]")
syncChan2 <- struct{}{}
}()
go func() {
; i < ; i++ {
dataChan <- i
fmt.Printf("Sent: %d [sender]\n",i)
}
close(dataChan)
syncChan1 <- struct{}{}
fmt.Println("Done. [sender]")
syncChan2 <- struct{}{}
}()
<- syncChan2
<- syncChan2
}
chanclose
4.3.2 单向channel
package main
import (
"fmt"
"time"
)
)
func main() {
syncChan1 := make(chan )
syncChan2 := make(chan )
go receive(strChan,syncChan1,syncChan2)
go send(strChan,syncChan1,syncChan2)
<- syncChan2
<- syncChan2
}
func send(strChan chan<- string,syncChan1 chan<- struct{},syncChan2 chan<- struct{}) {
for _,elem := range []string{"a","b","c","d"} {
strChan <- elem
fmt.Println("Sent:",elem,"[sender]")
if elem == "c" {
syncChan1 <- struct{}{}
fmt.Println("Sent a sync signal. [sender]")
}
}
fmt.Println("Wait 2 seconds... [sender]")
time.Sleep(time.Second * )
close(strChan)
syncChan2 <- struct{}{}
}
func receive(strChan <-chan string,syncChan1 <-chan struct{},syncChan2 chan<- struct{}) {
<- syncChan1
fmt.Println("Received a sync signal and wait a second... [receiver]")
time.Sleep(time.Second)
for {
if elem,ok := <- strChan;ok {
fmt.Println("Received:",elem,"[receiver]")
} else {
break
}
}
fmt.Println("Stopped. [receiver]")
syncChan2 <- struct{}{}
}
chanbase2
package main
import "fmt"
func main() {
var ok bool
ch := make(chan )
_,ok = interface{}(ch).(<-chan int)
fmt.Println("chan int => <-chan int:",ok)
_,ok = interface{}(ch).(chan<- int)
fmt.Println("chan int => chan<- int:",ok)
sch := make(chan<- )
_,ok = interface{}(sch).(chan int)
fmt.Println("chan<- int => chan int:",ok)
rch := make(<-chan )
_,ok = interface{}(rch).(chan int)
fmt.Println("<-chan int => chan int:",ok)
}
chanconv
4.3.3 for语句与channel
package main
import (
"fmt"
"time"
)
)
func main() {
syncChan1 := make(chan )
syncChan2 := make(chan )
go receive(strChan,syncChan1,syncChan2)
go send(strChan,syncChan1,syncChan2)
<-syncChan2
<-syncChan2
}
func receive(strChan <-chan string,syncChan1 <-chan struct{},syncChan2 chan<- struct{}) {
<-syncChan1
fmt.Println("Received a sync signal and wait a second... [receiver]")
time.Sleep(time.Second)
for elem := range strChan {
fmt.Println("Received:",elem,"[receiver]")
}
fmt.Println("Stopped. [receiver]")
syncChan2 <- struct{}{}
}
func send(strChan chan<- string,syncChan1 chan<- struct{},syncChan2 chan<- struct{}) {
for _,elem := range []string{"a","b","c","d"} {
strChan <- elem
fmt.Println("Sent:",elem,"[sender]")
if elem == "c" {
syncChan1 <- struct{}{}
fmt.Println("Sent a sync signal. [sender]")
}
}
fmt.Println("Wait 2 seconds... [sender]")
time.Sleep(time.Second * )
close(strChan)
syncChan2 <- struct{}{}
}
chanbase3
4.3.4 select语句
package main
import "fmt"
var intChan1 chan int
var intChan2 chan int
var channels = []chan int{intChan1,intChan2}
,,,,}
func main() {
select {
) <- getNumber():
fmt.Println("1th case is selected.")
) <- getNumber():
fmt.Println("The 2nd case is selected.")
default:
fmt.Println("Default")
}
}
func getNumber(i int) int {
fmt.Printf("numbers[%d]\n",i)
return numbers[i]
}
func getChan(i int) chan int {
fmt.Printf("channel[%d]\n",i)
return channels[i]
}
selecteval
package main
import "fmt"
func main() {
chanCap :=
intChan := make(chan int,chanCap)
; i < chanCap; i++ {
select {
:
:
:
}
}
; i < chanCap; i++ {
fmt.Printf("%d\n",<-intChan)
}
}
selectrandom
package main
import "fmt"
func main() {
intChan := make(chan )
; i < ; i++ {
intChan <-
}
close(intChan)
syncChan := make(chan )
go func() {
Loop:
for {
select {
case e,ok := <-intChan:
if !ok {
fmt.Println("End.")
break Loop
}
fmt.Printf("Received: %v\n",e)
}
}
syncChan <- struct{}{}
}()
<-syncChan
}
selectfor
4.3.5 非缓冲的channel
package main
import (
"time"
"fmt"
)
func main() {
sendingInterval := time.Second
receptionInterval := time.Second *
intChan := make(chan )
go func() {
var ts0,ts1 int64
; i <= ; i++ {
intChan <- i
ts1 = time.Now().Unix()
{
fmt.Println("Sent:",i)
} else {
fmt.Printf("Sent: %d [interval: %d s]\n",i,ts1-ts0)
}
ts0 = time.Now().Unix()
time.Sleep(sendingInterval)
}
close(intChan)
}()
var ts0,ts1 int64
Loop:
for {
select {
case v,ok := <- intChan:
if !ok {
break Loop
}
ts1 = time.Now().Unix()
{
fmt.Println("Received:",v)
} else {
fmt.Printf("Received: %d [interval: %d s]\n",v,ts1 - ts0)
}
}
ts0 = time.Now().Unix()
time.Sleep(receptionInterval)
}
fmt.Println("End.")
}
chan0cap
4.3.6 time包与channel
package main
import (
"time"
"fmt"
)
func main() {
timer := time.NewTimer( * time.Second)
fmt.Printf("Present time: %v.\n",time.Now())
expirationTime := <- timer.C
fmt.Printf("Expiration time: %v.\n",expirationTime)
fmt.Printf("Stop timer: %v.\n",timer.Stop())
}
timerbase
package main
import (
"fmt"
"time"
)
func main() {
intChan := make(chan )
go func() {
time.Sleep(time.Second)
intChan <-
}()
select {
case e := <- intChan:
fmt.Printf("Received: %v\n",e)
).C:
fmt.Println("Timeout!")
}
}
chantimeout1
package main
import (
"time"
"fmt"
)
func main() {
intChan := make(chan )
go func() {
; i < ; i++ {
time.Sleep(time.Second)
intChan <- i
}
close(intChan)
}()
timeout := time.Millisecond *
var timer * time.Timer
for {
if timer == nil {
timer = time.NewTimer(timeout)
} else {
timer.Reset(timeout)
}
select {
case e,ok := <- intChan:
if !ok {
fmt.Println("End.")
return
}
fmt.Printf("Received: %v\n",e)
case <- timer.C:
fmt.Println("Timeout!")
}
}
}
chantimeout2
package main
import (
"time"
"fmt"
)
func main() {
intChan := make(chan )
ticker := time.NewTicker(time.Second)
go func() {
for _ = range ticker.C {
select {
:
:
:
}
}
fmt.Println("End. [sender]")
}()
var sum int
for e := range intChan {
fmt.Printf("Received: %v\n",e)
sum += e
{
fmt.Printf("Got: %v\n",sum)
break
}
}
fmt.Println("End. [receiver]")
}
tickercase
4.4 实战演练:载荷发生器
4.4.1 参数和结果
4.4.2 基本构造
4.4.3 初始化
4.4.4 启动和停止
4.4.5 调用器和功能测试
4.5 小结
第5章 同步
5.1 锁的使用
5.1.1 互斥锁
package main
import (
"sync"
"fmt"
"time"
)
func main() {
var mutex sync.Mutex
fmt.Println("Lock the lock. (main)")
mutex.Lock()
fmt.Println("The lock is locked. (main)")
; i <= ; i++ {
go func(i int) {
fmt.Printf("Lock the lock. (g%d)\n",i)
mutex.Lock()
fmt.Printf("The lock is locked. (g%d)\n",i)
}(i)
}
time.Sleep(time.Second)
fmt.Println("Unlock the lock. (main)")
mutex.Unlock()
fmt.Println("The lock is unlocked. (main)")
time.Sleep(time.Second)
}
repeatedlylock
package main
import (
"sync"
"fmt"
)
func main() {
defer func() {
fmt.Println("Try to recover the panic.")
if p := recover(); p != nil {
fmt.Printf("Recovered the panic(%#v).\n",p)
}
}()
var mutex sync.Mutex
fmt.Println("Lock the lock.")
mutex.Lock()
fmt.Println("The lock is locked.")
fmt.Println("Unlock the lock.")
mutex.Unlock()
fmt.Println("The lock is unlocked.")
fmt.Println("Unlock the lock again.")
mutex.Unlock()
}
repeatedlyunlock
5.1.2 读写锁
5.1.3 锁的完整示例
5.2 条件变量
5.3 原子操作
5.3.1 增或减
5.3.2 比较并交换
5.3.3 载入
5.3.4 存储
5.3.5 交换
5.3.6 原子值
package main
import (
"sync/atomic"
"fmt"
)
func main() {
var countVal atomic.Value
countVal.Store([],,,})
anotherStore(countVal)
fmt.Printf("The count value: %+v \n",countVal.Load())
}
func anotherStore(countVal atomic.Value) {
countVal.Store([],,,})
}
copiedvalue
5.3.7 应用于实际
5.4 只会执行一次
5.5 WaitGroup
5.6 临时对象池
5.7 实战演练-Concurrent Map
5.8 小结
第6章 网络爬虫框架设计和实现
6.1 网络爬虫与框架
6.2 功能需求和分析
6.3 总体设计
6.4 详细设计
6.4.1 基本数据结构
6.4.2 接口的设计
6.5 工具的实现
6.5.1 缓冲器
6.5.2 缓冲池
6.5.3 多重读取器
6.6 组件的实现
6.6.1 内部基础接口
6.6.2 组件注册器
6.6.3 下载器
6.6.4 分析器
6.6.5 条目处理管道
6.7 调度器的实现
6.7.1 基本结构
6.7.2 初始化
6.7.3 启动
6.7.4 停止
6.7.5 其他方法
6.7.6 总结
6.8 一个简单的图片爬虫
6.8.1 概述
6.8.2 命令参数
6.8.3 初始化调度器
6.8.4 监控调度器
6.8.5 启动调度器
6.9 扩展和思路
6.10 本章小结