服务器：

    import socket
    import threading
    import time
    def tcplink(sock,addr):
        print('Accpet new connection from %s:%s...' % addr)
        sock.send(b'Welcome!')
        while True:
            #接收1kb的大小
            data = sock.recv(1024)
            #等待1
            time.sleep(1)
            #如果dat为空 或者 data收到'exit'则退出
            if not data or data.decode('utf-8') == 'exit':
                break
            #发送Hello + data 
            sock.send(('Hello, %s!' % data.decode('utf-8')).encode('utf-8'))
        sock.close()
        print('Connection from %s :%s closed.' %addr)
    #socket.SOCK_STREAM是针对tcp的，UDP是用socket.DGRAM
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.bind(('127.0.0.1',9999))
    s.listen(5)
    print('waiting for connection...')

    while True:
        sock , addr = s.accept()
        t = threading.Thread(target=tcplink, args=(sock, addr))
        t.start()

客户端

import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('127.0.0.1',9999))
print(s.recv(1024).decode('utf-8'))
for data in [b'AAA', b'BBB', b'CCC']:
    s.send(data)
    print(s.recv(1024).decode('utf-8'))
s.send(b'exit')
s.close()