Socket programming server and client (multiple clients can connect to the same port of a server at the same time)

Server code

[C-sharp]
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1. Using system;
2. Using system. Collections. Generic;
3. Using system. text;
4. Using system. net;
5. Using system. net. Sockets;
6. Using system. Threading;
7. Namespace TCP Communication
8. {
9. Class Program
10. {
11. Static void main (string [] ARGs)
12. {
13. Try
14. {
15. // Convert an IP address to an instance
16. IPaddress IPA = IPaddress. parse ("127.0.0.1 ");
17. // Listening port 8001
18. Tcplistener mylsn = new tcplistener (IPA, 8001 );
19. // Enable the listener
20. Mylsn. Start ();
21. // Output successful listening Information
22. Console. writeline ("starting service in 8001, waiting for connection ");
23. // Wait for processing the Access Connection Request
24. While (true)
25. {
26. Socket mysock = mylsn. acceptsocket ();
27. Console. writeline ("connected, connected from" + mysock. remoteendpoint );
28. Work W = new work ();
29. W. mysock = mysock;
30. W. mylsn = mylsn;
31. Thread t = new thread (New threadstart (W. Main ));
32. T. Start ();
33. }
34. }
35. Catch
36. {}
37. Finally
38. {}
39. }
40. }
41. Public class work
42. {
43. Public socket mysock;
44. Public tcplistener mylsn;
45. Public void main ()
46. {
47. // Receives client messages
48. Byte [] DATA = new byte [100];
49. Mysock. Receive (data );
50. String RT = system. Text. utf8encoding. utf8.getstring (data );
51. Console. writeline (RT );
52. // Send a message to the client
53. Mysock. Send (utf8encoding. utf8.getbytes ("send back to client "));
54. // Release resources
55. Mysock. Close ();
56. Mylsn. Stop ();
57. }
58. }
59. }

 

Client code

[C-sharp]
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1. Using system;
2. Using system. Collections. Generic;
3. Using system. text;
4. Using system. IO;
5. Using system. net;
6. Using system. net. Sockets;
7. Namespace TCP communication Client
8. {
9. Public class class1
10. {
11. Public static void main ()
12. {
13. // Create a client socket
14. Tcpclient tclient = new tcpclient ();
15. // Connect to the server
16. Tclient. Connect ("127.0.0.1", 8001 );
17. Console. writeline ("Enter the message to be sent ");
18. // Read the characters to be transmitted
19. String STR = console. Readline ();
21. // Get the stream
22. Stream STM = tclient. getstream ();
23. // Send a string
24. Asciiencoding ASEN = new asciiencoding ();
25. Byte [] DATA = Asen. getbytes (STR );
26. STM. Write (data, 0, Data. Length );
27. // Accept the message returned by the server
28. Byte [] Back = new byte [100];
29. Int K = STM. Read (back, 0,100 );
30. // Output the message returned by the server
31. For (INT I = 0; I <K; I ++)
32. {
33. Console. Write (convert. tochar (back [I]);
34. }
35. // Close the connection
36. Tclient. Close ();
37. }
38. }
39. }

 

According to the original design intention of the TCP/IP designer, when mysock. Close () is used to view the local connection with the command netstat-a-n, the corresponding link status is time_wait. The system automatically closes the connection.

Server code

[C-sharp]
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1. Using system;
2. Using system. Collections. Generic;
3. Using system. text;
4. Using system. net;
5. Using system. net. Sockets;
6. Using system. Threading;
7. Namespace TCP Communication
8. {
9. Class Program
10. {
11. Static void main (string [] ARGs)
12. {
13. Try
14. {
15. // Convert an IP address to an instance
16. IPaddress IPA = IPaddress. parse ("127.0.0.1 ");
17. // Listening port 8001
18. Tcplistener mylsn = new tcplistener (IPA, 8001 );
19. // Enable the listener
20. Mylsn. Start ();
21. // Output successful listening Information
22. Console. writeline ("starting service in 8001, waiting for connection ");
23. // Wait for processing the Access Connection Request
24. While (true)
25. {
26. Socket mysock = mylsn. acceptsocket ();
27. Console. writeline ("connected, connected from" + mysock. remoteendpoint );
28. Work W = new work ();
29. W. mysock = mysock;
30. W. mylsn = mylsn;
31. Thread t = new thread (New threadstart (W. Main ));
32. T. Start ();
33. }
34. }
35. Catch
36. {}
37. Finally
38. {}
39. }
40. }
41. Public class work
42. {
43. Public socket mysock;
44. Public tcplistener mylsn;
45. Public void main ()
46. {
47. // Receives client messages
48. Byte [] DATA = new byte [100];
49. Mysock. Receive (data );
50. String RT = system. Text. utf8encoding. utf8.getstring (data );
51. Console. writeline (RT );
52. // Send a message to the client
53. Mysock. Send (utf8encoding. utf8.getbytes ("send back to client "));
54. // Release resources
55. Mysock. Close ();
56. Mylsn. Stop ();
57. }
58. }
59. }

 

Client code

[C-sharp]
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1. Using system;
2. Using system. Collections. Generic;
3. Using system. text;
4. Using system. IO;
5. Using system. net;
6. Using system. net. Sockets;
7. Namespace TCP communication Client
8. {
9. Public class class1
10. {
11. Public static void main ()
12. {
13. // Create a client socket
14. Tcpclient tclient = new tcpclient ();
15. // Connect to the server
16. Tclient. Connect ("127.0.0.1", 8001 );
17. Console. writeline ("Enter the message to be sent ");
18. // Read the characters to be transmitted
19. String STR = console. Readline ();
21. // Get the stream
22. Stream STM = tclient. getstream ();
23. // Send a string
24. Asciiencoding ASEN = new asciiencoding ();
25. Byte [] DATA = Asen. getbytes (STR );
26. STM. Write (data, 0, Data. Length );
27. // Accept the message returned by the server
28. Byte [] Back = new byte [100];
29. Int K = STM. Read (back, 0,100 );
30. // Output the message returned by the server
31. For (INT I = 0; I <K; I ++)
32. {
33. Console. Write (convert. tochar (back [I]);
34. }
35. // Close the connection
36. Tclient. Close ();
37. }
38. }
39. }

 

According to the original design intention of the TCP/IP designer, when mysock. Close () is used to view the local connection with the command netstat-a-n, the corresponding link status is time_wait. The system automatically closes the connection.