做一个socket客户端
1、声明一个实例
2、绑定端口号和地址
3、循环发送和接收响应
其中要注意粘包的产生，为了防止粘包的产生，应该在服务器端先测出要发送信息的大小，
然后发送响应至客户端，等到服务器上一条信息发送完毕，客户再响应准备好接收下一条信息
这样就不会有粘包的产生
import socket
client = socket.socket()

client.connect(('localhost',9999))

while True:
    cmd = input(">>:").strip()
    if len(cmd) == 0:continue
    client.send(cmd.encode("utf-8"))
    cmd_res_size = client.recv(1024)
    print("命令结果大小：",cmd_res_size)
    client.send("我准备好了".encode("utf-8"))  #响应服务器端发送请求，为防止粘包的产生
    received_size = 0
    received_data =b''
    while received_size < int(cmd_res_size.decode()):
        data = client.recv(1024)
        received_size += len(data)
        received_data += data
    else:
        print("cmd res receive done...",received_size)
        print(received_data.decode())

client.close()