go's helloWorld

package main

import (
    "fmt"
    "net/http"
    "time"
)

func main() {
    //原始版
    helloWorld1()
    //http版
    helloWorld2()
    // go 协程版
    for i := 0; i < 5; i++ {
        go helloWorld3(i)
    }
    time.Sleep(time.Microsecond) // 添加延时，协程才有机会在main()主协程退出前执行

    //go + channel
    ch := make(chan string)
    for i := 0; i < 5; i++ {
        go helloWorld4(i, ch)
    }
    for {
        msg := <-ch
        fmt.Println(msg)
    }

}

func helloWorld1() {
    fmt.Println("hello world")
}

func helloWorld2() {
    http.HandleFunc("/", func(writer http.ResponseWriter, request *http.Request) {
        fmt.Fprintf(writer, "<h1>hello world %v</h1>", request.FormValue("name"))
    })
    http.ListenAndServe(":8888", nil)
}

func helloWorld3(i int) {
    fmt.Printf("hello world from goroutine %v \n", i)
}

func helloWorld4(i int, ch chan string) {
    for {
        ch <- fmt.Sprintf("hello world %v", i)
    }
}