1. Network Programming Introduction
Based on Classes in the java.net package
9/13/2018
V.B.Sanghavi

2. JAVA Networking API series of layered abstractions
basic networking capabilities are split between the java.net and the java.io
defining custom protocols, using existing protocols, or building a higher-level API on top of the basic services
9/13/2018
V.B.Sanghavi

3. Low Level API
Addresses, which are networking identifiers, like IP addresses.
Sockets, which are basic bidirectional data communication mechanisms.
Interfaces, which describe network interfaces.
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V.B.Sanghavi

4. High Level API URIs, which represent Universal Resource Identifiers.
URLs, which represent Universal Resource Locators.
Connections, which represents connections to the resource pointed to by URLs.
9/13/2018
V.B.Sanghavi

5. Network Terminology IP Address
Connection-oriented (TCP) and connectionless protocol (UDP)
Protocol
Socket –allows a single comp. to serve diff.clients at once.
Port Number –numbered socket
Domain Naming Service(DNS)
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V.B.Sanghavi

6. Client-server Architecture
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V.B.Sanghavi

7. Networking Classes InetAddress Socket ServerSocket URL URLConnection
DatagramSocket
DatagramPacket
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V.B.Sanghavi

8. InetAddress
Encapsulates the Numerical IP address and domain name for that address.
Interact with this class by hostname as it is more convenient.
Can handle IPv4 and IPv6 addresses.
9/13/2018
V.B.Sanghavi

9. Factory Methods
static InetAddress getLocalHost() throws UnknownHostException
static InetAddress getByName(String hostname) throws UnknownHostException
Static InetAddress[] getAllByName() throws UnknownHostException
9/13/2018
V.B.Sanghavi

10. static InetAddress getByAddress() throws UnknownHostException
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V.B.Sanghavi

11. Instance Methods Boolean equals(Object o) Byte[] getAddress()
String getHostAddress()
String getHostName()
Boolean isMulticastAddress()
String toString()
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V.B.Sanghavi

12. Socket Programming for communication between the machines.
The client in socket programming must know two information:
IP address
Port number
9/13/2018
V.B.Sanghavi

13. Socket class endpoint for communications between the machines.
create a socket to connect to a server sockets and initiate protocol exchange.
Constructor
Socket (String host, int port)
Socket ( InetAddress ip, int port)
program
9/13/2018
V.B.Sanghavi

14. - inetAddress getInetAddress() int getPort() int getLocalPort()
Methods :
- inetAddress getInetAddress()
int getPort()
int getLocalPort()
9/13/2018
V.B.Sanghavi

15. - public InputStream getInputStream()
Socket class
Methods:
- public InputStream getInputStream()
- public OutputStream getOutputStream() - void close()
9/13/2018
V.B.Sanghavi

16. ServerSocket class
to create a server socket that listen for local or remote client program.
Constructor:
ServerSocket (int port)
ServerSocket (int port, int maxqueue)
ServerSocket ( int port, int maxqueue, InetAddress i)
program
9/13/2018
V.B.Sanghavi

17. - public Socket accept() - public InputStream getInputStream()
Methods:
- public Socket accept()
- public InputStream getInputStream()
- public OutputStream getOutputStream() - void close()
9/13/2018
V.B.Sanghavi

18. URL class
represents a URL (Uniform Resource Locator) to uniquely identify or address info. On the internet.
URLs can point to files, Web sites, ftp sites, newsgroups, addresses, and other resources.
9/13/2018
V.B.Sanghavi

19. Format of URL http://www.javatpoint.com : 8080/abc / index.jsp
telnet://localhost:8000/
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V.B.Sanghavi

20. URL constructors URL (String urlspecifier)
URL ( String protocol, String host, int port, String path)
Exception : MalformedURLException
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V.B.Sanghavi

21. Methods of URL class public String getProtocol()
public String getHost()
public String getPort()
public String getFile()
Public String toExternalForm()
Program
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V.B.Sanghavi

22. URLConnection
represents a communication link between the URL and the application.
can be used to read and write data to the specified resource reffered by the URL.
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V.B.Sanghavi

23. Creating a URLConnection
URL url = new URL ( some_url );
URLConnection connection = url.openConnection();
9/13/2018
V.B.Sanghavi

24. public String getContentType() public long getExpiration()
public long getDate()
public String getContentType()
public long getExpiration()
public long getLastModified()
public int getContentLength()
public InputStream getInputStream()
public OutputStream getOutputStream()
9/13/2018
V.B.Sanghavi

25. Program for URLConnection class to read the content of specified resource
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V.B.Sanghavi

26. Datagrams Bundles of information passed between machines.
When released- no assurance regarding arrival.
When received- no assurance regarding data reliability.
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V.B.Sanghavi

27. DatagramSocket class
represents a connection-less socket for sending and receiving datagram packets
Constructors
DatagramSocket() //Sending
DatagramSocket(int port) //receiving
DatagramSocket(int port, InetAddress address)
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V.B.Sanghavi

28. DatagramPacket class
The DatagramPacket is message that can be sent or received
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V.B.Sanghavi

29. Constructors DatagramPacket(byte[] data, int length)
(While receiving the data)
DatagramPacket(byte[] data, int length, InetAddress address, int port)
(while sending the data)
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V.B.Sanghavi

30. Methods: InetAddress getAddress() Int getPort() byte[] getData()
Int getLength()
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V.B.Sanghavi

31. Content Handler and Protocol Handler
Handling a protocol
taking care of the interaction between a client and a server
generating requests in the correct format
acknowledging that the data has been received
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V.B.Sanghavi

32. Handling the content
converting the raw data into a format Java understands
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V.B.Sanghavi

33. ContentHandler implemented as subclasses of the ContentHandler
getContent()
associated with a specific MIME type through the use of the ContentHandlerFactory interface
createContentHandler()
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V.B.Sanghavi

34. ProtocolHandler
implemented as subclasses of the URLStreamHandler class
openConnection()
toExternalForm()
to implement a custom protocol needed to access Web objects identified by URLs
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V.B.Sanghavi

35. createURLStreamHandler()
associated with a specific protocol through the use of the URLStreamHandlerFactory
createURLStreamHandler()
9/13/2018
V.B.Sanghavi