ServerSocket表示服务器上的套接字，该套接字等待并侦听来自客户端的服务。套接字表示服务器和客户端之间通信的端点。当服务器获得作为服务请求，它创建一个套接字与客户端进行通信，并继续侦听ServerSocket上的其他请求。客户端还创建一个套接字，以便与服务器进行通信。(ServerSocket represents the socket on a server that waits and listens for service
from a client. Socket represents the endpoints for communication between a server
and a client. When a server gets a request for service, it creates a Socket for
communication with the client and continues to listen for other requests on the
ServerSocket. The client also creates a Socket for communication with the
server.)