Two small exercises about TCP _ The first blog ~, First blog of tcp exercises

Two small exercises about TCP _ The first blog ~, First blog of tcp exercises

First, a local client sends a request, and the server receives the simple code of the request.

1 package com. TCP. java; 2 3 import java. io. IOException; 4 import java. io. inputStream; 5 import java. io. outputStream; 6 import java.net. inetAddress; 7 import java.net. serverSocket; 8 import java.net. socket; 9 import org. junit. test; 10 11 // the client sends a message to the server. The server outputs this information to 12 public class TestTCP {13 // client 14 @ Test15 public void client () {16 Socket socket = null; 17 OutputStream OS = null; 18 try {19 // 1. create a Socket object, specify the IP address of the server through the constructor, and the port number of the receiving program 20 socket = new Socket (InetAddress. getByName ("192.168.1.101"), 9090); 21 // 2. getOutputStream (): sends data. The method returns the OutputStream object 22 OS = socket. getOutputStream (); 23 // 3. specific output process 24 OS. write ("I Am a client ". getBytes (); 25} catch (IO Exception e) {26 e. printStackTrace (); 27} finally {28 // close the corresponding stream and Socket object 29 try {30 if (OS! = Null) {31 OS. close (); 32} 33 if (socket! = Null) {34 socket. close (); 35} 36} catch (IOException e) {37 e. printStackTrace (); 38} 39} 40} 41 42 // server 43 @ Test44 public void server () {45 ServerSocket ss = null; 46 Socket s = null; 47 InputStream is = null; 48 try {49 // 1. create a ServerSocket object and specify its own port number through the constructor: 50 ss = new ServerSocket (9090); 51 // 2. call its accept () method and return a Socket object 52 s = ss. accept (); 53 // 3. call the getInputStream () method of the Socket object to obtain an input stream sent from the client 54 is = S. getInputStream (); 55 // 4. operate the obtained stream 56 byte [] B = new byte [20]; 57 int length; 58 while (length = is. read (B ))! =-1) {59 String str = new String (B, 0, length); 60 System. out. println (str); 61} 62 System. out. println ("received from" + s. getInetAddress (). getHostName () + "connection"); 63} catch (IOException e) {64 e. printStackTrace (); 65} finally {66 // close the corresponding stream, Socket, ServerSocket object 67 if (is! = Null) {68 try {69 is. close (); 70} catch (IOException e) {71 e. printStackTrace (); 72} 73} 74 if (s! = Null) {75 try {76 s. close (); 77} catch (IOException e) {78 e. printStackTrace (); 79} 80} 81 if (ss! = Null) {82 try {83 ss. close (); 84} catch (IOException e) {85 e. printStackTrace (); 86} 87} 88} 89} 90}

 

In a more complex way, when the server receives a request from the client, it gives a friendly feedback.

 

1 package com. TCP. java; 2 3 import java. io. IOException; 4 import java. io. inputStream; 5 import java. io. outputStream; 6 import java.net. inetAddress; 7 import java.net. serverSocket; 8 import java.net. socket; 9 import java.net. unknownHostException; 10 11 import org. junit. test; 12 13 // the client sends information to the server, and the server prints the information to the console, send "received message" to client 14 public class TestTCP2 {15 // client 16 @ Test 17 public void client () {18 Sock Et s = null; 19 OutputStream OS = null; 20 InputStream is = null; 21 try {22 s = new Socket (InetAddress. getByName ("192.168.1.101"), 9797); 23 OS = s. getOutputStream (); 24 OS. write ("I Am a client ". getBytes (); 25 26 // shutdownOutput (): execute this method to explicitly tell the server that the message has been sent for 27 s. shutdownOutput (); 28 29 is = s. getInputStream (); 30 byte [] B = new byte [20]; 31 int length; 32 while (length = is. read (B ))! =-1) {33 String str = new String (B, 0, length); 34 System. out. println (str); 35} 36} catch (UnknownHostException e) {37 // TODO Auto-generated catch block 38 e. printStackTrace (); 39} catch (IOException e) {40 // TODO Auto-generated catch block 41 e. printStackTrace (); 42} 43 if (is! = Null) {44 try {45 is. close (); 46} catch (IOException e) {47 // TODO Auto-generated catch block 48 e. printStackTrace (); 49} 50} 51 if (OS! = Null) {52 try {53 OS. close (); 54} catch (IOException e) {55 // TODO Auto-generated catch block 56 e. printStackTrace (); 57} 58} 59 if (s! = Null) {60 try {61 s. close (); 62} catch (IOException e) {63 // TODO Auto-generated catch block 64 e. printStackTrace (); 65} 66} 67} 68 // server 69 @ Test 70 public void server () {71 ServerSocket ss = null; 72 Socket s = null; 73 InputStream is = null; 74 OutputStream OS = null; 75 try {76 ss = new ServerSocket (9797); 77 s = ss. accept (); 78 is = s. getInputStream (); 79 80 byte [] B = new byte [20]; 81 int length; 82 while (length = is. read (B ))! =-1) {83 String str = new String (B, 0, length); 84 System. out. println (str); 85} 86 87 OS = s. getOutputStream (); 88 OS. write ("received request ". getBytes (); 89} catch (IOException e) {90 // TODO Auto-generated catch block 91 e. printStackTrace (); 92} 93 finally {94 if (OS! = Null) {95 try {96 OS. close (); 97} catch (IOException e) {98 // TODO Auto-generated catch block 99 e. printStackTrace (); 100} 101} 102 if (is! = Null) {103 try {104 is. close (); 105} catch (IOException e) {106 // TODO Auto-generated catch block107 e. printStackTrace (); 108} 109} 110 if (s! = Null) {111 try {112 s. close (); 113} catch (IOException e) {114 // TODO Auto-generated catch block115 e. printStackTrace (); 116} 117} 118 if (ss! = Null) {119 try {120 ss. close (); 121} catch (IOException e) {122 // TODO Auto-generated catch block123 e. printStackTrace (); 124} 125} 126} 127} 128}