IADCS Diploma Course Java Network Programming U Nyein Oo COO/Director(IT) Myanma Computer Co., Ltd

Objectives Introduction to Internet and its working Network Protocol TCP and UDP Explain Client/Server computing Classes of java.net package: InetAddress Socket ServerSocket DatagramSocket DatagramPacket

Introduction to Internet and its working

Network Protocol

TCP and UDP

Explain Client/Server computing

Classes of java.net package:

InetAddress

Socket

ServerSocket

DatagramSocket

DatagramPacket

Objectives(cont) Explain Web related classes: URL Class URLConnection Class URLEncoder Class ContentHandler Class

Explain Web related classes:

URL Class

URLConnection Class

URLEncoder Class

ContentHandler Class

Networking and Internet Networking is the concept of connecting two machines Internet is nothing but many computers communicating with each other using protocols

Networking is the concept of connecting two machines

Internet is nothing but many computers communicating with each other using protocols

Protocol Protocols help in passing information from one computer to another Computers communicate with each other by exchanging packets of data Internet Protocol (IP) is the network protocol used to send information from one computer to another over the Internet

Protocols help in passing information from one computer to another

Computers communicate with each other by exchanging packets of data

Internet Protocol (IP) is the network protocol used to send information from one computer to another over the Internet

Protocol (Contd…) The communication of computers is possible using Ports Commonly used port numbers Port No Protocol Description 21 FTP File Transfer Protocol 23 TELNET Remote Login 25 SMTP Simple Mail Transfer Protocol

The communication of computers is possible using Ports

Commonly used port numbers

TCP and UDP Communication takes place with the help of transport protocols TCP establishes link between the source port’s IP address and destination port’s IP address

Communication takes place with the help of transport protocols

TCP establishes link between the source port’s IP address and destination port’s IP address

TCP and UDP (Contd…) UDP is a connectionless protocol as it does not establish a link for the connection When UDP is used, the destination port and IP addresses are written down in a datagram and the datagram is sent to the destination UDP is less reliable as compared to TCP since there is no delivery assurance

UDP is a connectionless protocol as it does not establish a link for the connection

When UDP is used, the destination port and IP addresses are written down in a datagram and the datagram is sent to the destination

UDP is less reliable as compared to TCP since there is no delivery assurance

Client Server Computing The Net provides a variety of services; these services are organized according to the client/server architecture The client programs like browsers create connections to server programs such as Web and FTP servers

The Net provides a variety of services; these services are organized according to the client/server architecture

The client programs like browsers create connections to server programs such as Web and FTP servers

Client Server Computing (Contd…) The client makes the request to the server and the server responds by providing the required service to the client Clients communicate through client sockets and servers communicate through server sockets

The client makes the request to the server and the server responds by providing the required service to the client

Clients communicate through client sockets and servers communicate through server sockets

Inside java.net The java.net package provides the classes that support socket-based client/server communication Classes of java.net package: InetAddress Socket ServerSocket DatagramSocket DatagramPacket

The java.net package provides the classes that support socket-based client/server communication

Classes of java.net package:

InetAddress

Socket

ServerSocket

DatagramSocket

DatagramPacket

InetAddress Class This class eases finding of addresses on the Internet Only the name needs to be supplied to get the respective address It supports both numeric IP address and hostnames

This class eases finding of addresses on the Internet

Only the name needs to be supplied to get the respective address

It supports both numeric IP address and hostnames

Socket Class Java programs connect to the network using a socket Socket helps in establishing connections and developing applications between the client and server

Java programs connect to the network using a socket

Socket helps in establishing connections and developing applications between the client and server

ServerSocket Class The TCP server socket is implemented using the ServerSocket class The server socket is made to listen using the accept( ) method and thereby wait till an incoming connection is established The address of the host to which the socket is connected is returned using getInetAddress( ) method

The TCP server socket is implemented using the ServerSocket class

The server socket is made to listen using the accept( ) method and thereby wait till an incoming connection is established

The address of the host to which the socket is connected is returned using getInetAddress( ) method

DatagramSocket Class This class is used to implement the client and server sockets using the User Datagram Protocol (UDP) UDP is a connectionless protocol that enables client and server to exchange information using datagrams Datagrams are nothing but chunks of data The datagrams are sent and received using the send( ) and receive( ) methods respectively

This class is used to implement the client and server sockets using the User Datagram Protocol (UDP)

UDP is a connectionless protocol that enables client and server to exchange information using datagrams

Datagrams are nothing but chunks of data

The datagrams are sent and received using the send( ) and receive( ) methods respectively

DatagramPacket Class This class encapsulates the datagrams that are sent and received using objects of DatagramSocket class There are two different constructors, one for datagrams that are received from the datagram socket and the other for creating datagrams that are sent over the datagram socket

This class encapsulates the datagrams that are sent and received using objects of DatagramSocket class

There are two different constructors, one for datagrams that are received from the datagram socket and the other for creating datagrams that are sent over the datagram socket

Web related classes While working with the Internet and World Wide Web, we need to create and manipulate URLs The java.net package also provides a set of classes that support Web-specific applications java.net web-related classes: URL URLConnection URLEncoder ContentHandler

While working with the Internet and World Wide Web, we need to create and manipulate URLs

The java.net package also provides a set of classes that support Web-specific applications

java.net web-related classes:

URL

URLConnection

URLEncoder

ContentHandler

URL Class URL stands for Uniform Resource Locator It provides a uniform way to locate resources on the web The class java.net.URL encapsulates the object on the web

URL stands for Uniform Resource Locator

It provides a uniform way to locate resources on the web

The class java.net.URL encapsulates the object on the web

URLConnection Class It is an abstract class If we have an active HTTP connection to the web, the URLConnection class encapsulates it This class supports several methods so as to modify the defaults, query and modify the current settings for a URLConnection object URLConnection class is used for getting information about the web object and the connection to the web object so as to interact with the web object HttpURLConnection is a subclass of the URLConnection class

It is an abstract class

If we have an active HTTP connection to the web, the URLConnection class encapsulates it

This class supports several methods so as to modify the defaults, query and modify the current settings for a URLConnection object

URLConnection class is used for getting information about the web object and the connection to the web object so as to interact with the web object

HttpURLConnection is a subclass of the URLConnection class

URLEncoder Class This class is basically used for converting text strings to a suitable form useable as part of an URL This class provides method called encode( ) that converts the spaces in the text to plus sign (+) It uses a percent character (%) as an escape code for encoding special characters

This class is basically used for converting text strings to a suitable form useable as part of an URL

This class provides method called encode( ) that converts the spaces in the text to plus sign (+)

It uses a percent character (%) as an escape code for encoding special characters

ContentHandler Class ContentHandler class is used to process and extract data with MIME (Multipurpose Internet Mail Extension) types MIME includes different types of objects such as sounds, images, videos, etc. It provides viewers to process MIME types

ContentHandler class is used to process and extract data with MIME (Multipurpose Internet Mail Extension) types

MIME includes different types of objects such as sounds, images, videos, etc.

It provides viewers to process MIME types