go socket server to handle multiple users

package main

import (
   "fmt"
   "net"
   "strings"
)

func main() {

   listener, err := net.Listen("tcp", "127.0.0.1:8000")
   if err != nil {
      fmt.Println(err.Error())
      return
   }
   defer listener.Close()
   //接收多个用户
   for {
      conn, err := listener.Accept()
      if err != nil {
         fmt.Println(err.Error())
         return
        }
       //处理用户的连接
       go handleConn(conn)

      }
}
 func handleConn(conn net.Conn){

   defer conn.Close()
    buff := make([]byte, 1024)
   for {
      n, err := conn.Read(buff)
      if err != nil {
         fmt.Println(err)
         return
      }
      content := string(buff[:n])
      fmt.Println("content=", string(buff[:n]))
      content = strings.ToUpper(content)
      conn.Write([]byte(content))
   }
 }