最简单的回声服务器:
package main import ( "io" "net" "log" ) 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 } } func handleConn(c net.Conn) { io.Copy(c, c) // NOTE: ignoring errors c.Close() }
原理:
1.io.Copy()方法
func Copy(dst Writer, src Reader) (written int64, err error)
2.net.Conn类型
type Conn interface {
Read(b []byte) (n int, err error)
Write(b []byte) (n int, err error)
…
}
一个类型如果拥有一个接口需要的所有方法,那么这个类型就实现了这个接口
3.io.Writer
type Writer interface {
Write(p []byte) (n int, err error)
}
4.io.Reader
type Reader interface {
Read(p []byte) (n int, err error)
}
升级版,每条连接一个goroutine,每个goroutine中分出多个输出goroutine
package main import ( "bufio" "fmt" "log" "net" "strings" "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 } } func handleConn(c net.Conn) { input := bufio.NewScanner(c) for input.Scan() { go echo(c, input.Text(), 1*time.Second) } // NOTE: ignoring potential errors from input.Err() c.Close() } func echo(c net.Conn, shout string, delay time.Duration) { 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)) }
1.fmt.Fprintln()
func Fprintln(w io.Writer, a …interface{}) (n int, err error)
2.bufio.NewScanner()
func NewScanner(r io.Reader) *Scanner
func (s *Scanner) Scan() bool
func (s *Scanner) Text() string
也用到了大量的7.3节 实现接口的条件
原创文章,作者:ItWorker,如若转载,请注明出处:https://blog.ytso.com/12531.html