2.6P2 Pfile sharing(P2P文件共享) 2.7 Socket Programming wth TCP(TCP套接字编程) 25分钟 2.7.1 Socket Programming wth TCP Socket APl explicitly created,used,released by apps client/server parad igm two types of transport service via socket API: unreliable datagram reliable,byte stream-oriented Client must contact server server process must first be running server must have created socket(door)that welcomes client's contact Client contacts server by: creating client-local TCP socket 25分钟 specifying Paddresspor number of erver proces 2.72 An Example Clients/Server Application in Java import ava.io.* mport javanet.◆： class TCPClient public statie vod main(String argv)throws Exeeption String sentence; String modifiedSentence: BufferedReader inFromUser Socket clientSocket =new Socket("hostname",6789). DataOutputStream outToServer 25分钟 new DataOutputStream(clientSocket.getOutputStream(): Buffered Reader infromServer new BufferedReader(new InputStreamReader(() sentence =inFromUser.readLine(); outToServerwriteBytes(sentence +'n'), modifiedSentence =inFromServerreadLine(): System.outprint("FROM SERVER:+modifedSentence) 讲解程序框图，讲解Java程序工作流程，用讨论式教学方式教学。) 13 Outlines, requirements and time allocation 2.6 P2P file sharing（P2P 文件共享） 2.7 Socket Programming wth TCP（TCP 套接字编程） 2.7.1 Socket Programming wth TCP Goal: learn how to build client/se rver application that communicate using sockets Socket API: introduced in BSD4.1 UNIX, 1981 explicitly created, used, released by apps client/server paradigm two types of transport service via socket API: unreliable datagram reliable, byte stream-oriented Client must contact server server process must first be running server must have created socket (door) that welcomes client’s contact Client contacts server by: creating client-local TCP socket specifying IP address, port number of server process 2.7.2 An Example Clients/Server Application in Java import java.io.*; import java.net.*; class TCPClient { public static void main(String argv[]) throws Exception { String sentence; String modifiedSentence; BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in)); Socket clientSocket = new Socket("hostname", 6789); DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream()); BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream())); sentence = inFromUser.readLine(); outToServer.writeBytes(sentence + '\n'); modifiedSentence = inFromServer.readLine(); System.out.println("FROM SERVER: " + modifiedSentence); clientSocket.close(); } } （讲解程序框图，讲解 Java 程序工作流程，用讨论式教学方式教学。） 25 分钟 25 分钟 25 分钟