Lập trình socket với java

Khoa Hc v K Thut Mỏy Tớnh
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Bi Ging 2
LP TRèNH MNG DNG SOCKET
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KHI NIM V SOCKET

Socket API

éc gii thiu BSD4.1 UNIX, 1981

éc ng dng khi to, s dng v hy b.

Dựng c ch client/server

Cung cp hai dch v chuyn d liu thụng qua
socket API:
unreliable datagram
reliable, byte stream-oriented
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KHI NIM V SOCKET
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THIT K GII THUT CLIENT/SERVER
Thi

t k

gi

i thu

t cho client
Gii thut cho chng trỡnh client dựng UDP

Xỏc nh a ch server.

To socket.

Gi/nhn d liu theo giao thc lp ng dng ó thit k.

úng socket.
Gii thut cho chng trỡnh client dựng TCP

Xỏc nh a ch server

To socket.

Kt ni n server.

Gi/nhn d liu theo giao thc lp ng dng ó thit k.

úng kt ni.
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THIT K GII THUT CLIENT/SERVER

Thit k gii thut cho Server

Chng trỡnh server cú hai loi:
L

p(iterative)


ng th

i (concurrent).

Hai dng giao thc chng trỡnh server:
Connection-oriented
Connectionless.
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THIT K GII THUT CLIENT/SERVER
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THIT K GII THUT CLIENT/SERVER
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THIT K GII THUT CLIENT/SERVER

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THIT K GII THUT CLIENT/SERVER
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THIT K GII THUT CLIENT/SERVER
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THIT K GII THUT CLIENT/SERVER
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LP TRèNH MNG TRấN JAVA

Gúi java.net
InetAddress
ServerSocket
Socket
URL
URLConnection
DatagramSocket
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LP TRèNH MNG TRấN JAVA

InetAddress class

Class mụ t

v

a ch

IP (Internet Protocol)
Cỏc ph

ng th

c getLocalHost, getByName, hay
getAllByName

t

o m

t InetAddress instance:
public static InetAddess InetAddress.getByName(String hostname)
public static InetAddess [] InetAddress.getAllByName(String
hostname)
public static InetAddess InetAddress.getLocalHost()


l

y

a ch

IP hay tờn dựng cỏc ph

ng th

c:
getHostAddress()
getHostName()
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LP TRèNH MNG TRấN JAVA
In

a ch

IP c

a localhost
import java.net.*;
public class HostInfo {
public static void main(String args[]) {
HostInfo host = new HostInfo();
host.init();
}
public void init() {
try {
InetAddress myHost = InetAddress.getLocalHost();
System.out.println(myHost.getHostAddress());
System.out.println(myHost.getHostName());

} catch (UnknownHostException ex) {
System.err.println("Cannot find local host");
}
}
}
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LP TRèNH MNG TRấN JAVA
In

a ch

IP c

a proxy.hcmut.edu.vn
import java.net.*;
class kku{
public static void main (String args[]) {
try {
InetAddress[] addresses =
InetAddress.getAllByName(proxy.hcmut.edu.vn");
for (int i = 0; i < addresses.length; i++) {
System.out.println(addresses[i]);
}
}
catch (UnknownHostException e) {
System.out.println("Could not find proxy.hcmut.edu.vn");
}
}

}
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LP TRèNH MNG TRấN JAVA

Cỏc chng trỡnh c thờm
T

o m

t

a ch

IP t

m

ng byte, chu

i String.
InetAddressFactory.java
Cho m

t

a ch

tỡm tờn mỏy.

ReverseTest.java
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LP TRèNH MNG TRấN JAVA
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LP TRèNH MNG TRấN JAVA

Socket class
Class mụ t

v

socket
T

o m

t socket
Socket(InetAddress address, int port)
Socket(String host, int port)
Socket(InetAddress address, int port, InetAddress, localAddr, int
localPort)
Socket(String host, int port, InetAddress, localAddr, int localPort)
Socket()
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LP TRèNH MNG TRấN JAVA
Socket class (ti

p theo)
Ly thụng tin v mt socket
InetAddress getInetAddress() : tr v a ch m socket kt ni
n.
int getPort() : tr v a ch m socket kt ni n.
InetAddress getLocalAddress() : tr v a ch cc b.
int getLocalPort() : tr v a ch cc b.
S dng Streams
public OutputStream getOutputStream() throws IOException
Tr v mt output stream cho vic vit cỏc byte n socket ny.
public InputStream getInputStream() throws IOException
Tr v mt input stream cho vic c cỏc byte t socket ny.
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LP TRèNH MNG TRấN JAVA
K

t n

i

ờn 1 s

webserver
import java.net.*;
import java.io.*;

public class getSocketInfo {
public static void main(String[] args) {
for (int i = 0; i < args.length; i++) {
try {
Socket theSocket = new Socket(args[i], 80);
System.out.println("Connected to " +
theSocket.getInetAddress() +
" on port " + theSocket.getPort() + " from port " +
theSocket.getLocalPort() + " of " +
theSocket.getLocalAddress());
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LP TRèNH MNG TRấN JAVA
K

t n

i

ờn 1 s

webserver (ti

p theo)
} catch (UnknownHostException e) {
System.err.println("I can't find " + args[i]);
} catch (SocketException e) {
System.err.println("Could not connect to " + args[i]);
} catch (IOException e) {

System.err.println(e);
}
} // end for
} // end main
} // end getSocketInfo
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LP TRèNH MNG TRấN JAVA

ServerSocket class
Class mụ t

v

ServerSocket
T

o m

t ServerSocket
ServerSocket(int port) throws IOException
ServerSocket(int port, int backlog) throws IOException
ServerSocket(int port, int backlog, InetAddress bindAddr) throws
IOException
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LP TRèNH MNG TRấN JAVA

ServerSocket class
Cỏc ph

ng th

c trong ServerSocket
Socket accept() throws IOException : Lng nghe mt kt ni n
socket ny v chp nhn nú.
void close() throws IOException : úng socket.
InetAddress getInetAddress() : tr v a ch cc b ca socket
int getLocalPort() : Tr v port m server ang lng nghe.
void setSoTimeout(int timeout) throws SocketException
Enable/disable SO_TIMEOUT vi khai bỏo timeout (milliseconds)
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LP TRèNH MNG TRấN JAVA
DateTime Server
import java.net.*;
import java.io.*;
import java.util.Date;
public class DayTimeServer {
public final static int daytimePort = 5000;
public static void main(String[] args) {
ServerSocket theServer;
Socket theConnection;
PrintStream p;
try {
theServer = new ServerSocket(daytimePort);
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LP TRèNH MNG TRấN JAVA
DateTime Server (ti

p theo)
while (true) {
theConnection = theServer.accept();
p =
new PrintStream(theConnection.getOutputStream());
p.println(new Date());
theConnection.close();
theServer.close();
}
}catch (IOException e) {
System.err.println(e);
}
}
}