你必须把所有的代码从 sc, address = s.accept() 到 sc.close() 进入另一个循环，或者服务器在收到第一个文件后简单地终止.它没有崩溃，脚本刚刚完成.

You must put all the code from sc, address = s.accept() upto sc.close() into another loop or the server simply terminates after receiving the first file. It doesn't crash, the script is just finished.

这是修改后的代码:

import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10) # Accepts up to 10 connections.

while True:
    sc, address = s.accept()

    print address
    i=1
    f = open('file_'+ str(i)+".pdf",'wb') #open in binary
    i=i+1
    while (True):       
    # receive data and write it to file
        l = sc.recv(1024)
        while (l):
                f.write(l)
                l = sc.recv(1024)
    f.close()


    sc.close()

s.close()

请注意，s.listen(10) 的意思是将最大接受率设置为 10 个连接"，而不是在 10 个连接后停止".

Note that s.listen(10) means "set maximum accept rate to 10 connections", not "stop after 10 connections".