Go语言圣经-基于select的多路复用习题详解编程语言

package main 
 
import ( 
        "bufio" 
        "fmt" 
        "log" 
        "net" 
        "strings" 
        "sync" 
        "time" 
) 
 
func main() { 
        listener, err := net.Listen("tcp", ":8040") 
        if err != nil { 
                log.Fatal(err) 
        } 
 
        for { 
                conn, err := listener.Accept() 
                if err != nil { 
                        log.Print(err) // e.g., connection aborted 
                        continue 
                } 
                go handleConn(conn) //新建goroutines处理连接 
        } 
} 
/* 
1.启动一个goroutine,for死循环让他不能断掉 
select语句case判断两个channel 
一个是10秒后断掉连接 
另一个是接收标准输入后发送过来的channel，接收到值后，启动goroutinue输出 
 
2.for循环接收标准输入，接收到后发送给message的channel 
*/ 
func handleConn(c net.Conn) { 
        input := bufio.NewScanner(c) 
        var wg sync.WaitGroup 
        var message = make(chan string) 
        wg.Add(1) 
        go func() { 
                defer wg.Done() 
                for { 
                        select { 
                        case <-time.After(10 * time.Second): 
                                c.Close() 
                        case mes := <-message: 
                                wg.Add(1) 
                                go func(c net.Conn, shout string, delay time.Duration) { 
                                        defer wg.Done() 
                                        fmt.Fprintln(c, "/t", strings.ToUpper(shout)) 
                                        time.Sleep(delay) 
                                        fmt.Fprintln(c, "/t", shout) 
                                        time.Sleep(delay) 
                                        fmt.Fprintln(c, "/t", strings.ToLower(shout)) 
                                        //ch<-struct{}{} 
 
                                }(c, mes, 1*time.Second) 
 
                        } 
                } 
        }() 
        for input.Scan() { 
                text := input.Text() 
                message <- text 
        } 
 
        wg.Wait() 
        //cw := c.(*net.TCPConn) 
        //cw.CloseWrite() 
 
        c.Close() 
}