Network Programming Tutorial: How To Create Connection Between Clie...

What Will I Learn?

You will learn how to create client and server program
You will learn how to make communication between two program
You will learn how to create connection between client and server
You will learn to create two class in one package on netbeans

Requirements

you must understand basic of java programming
you must understand how to create stucture beetween two progran on the package
you must know how to implement java program on netbeans IDE
The Java Software Development Kit must be installed on your system
Netbeans IDE should also be installed on your system

Difficulty

Basic

Tutorial Contents

first open netbeans IDE aplication

i use netbeans IDE 7.0.1 version
second, create new project, select java category, and in project select java aplication, then press next.

then write down the name of your project, hit finish
the next step is to create a file with the name client.java as in the picture below.

type the program below into the client program field, and I will explain a bit about the program below.

package clientserver;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
public class Client {
public static void main(String[] args)throws IOException {
Socket sock=new Socket("localhost", 6066);
DataInputStream in= new DataInputStream(sock.getInputStream());
System.out.println(in.readUTF());
DataOutputStream out =new DataOutputStream(sock.getOutputStream());
out.writeUTF("what is youre name");
sock.close();
}}

below is an explanation of the above program.
package clientserver;
this is the name of the package where the client server program is located

import java.io.DataInputStream;
Java DataInputStream class lets you read Java primitives (int, float, long etc.)

import java.io.DataOutputStream;
import java.io.DataOutputStream; allows the application to write Java primitive data types to output in a portable way. The application can then use the data input stream to re-read the data.

import java.io.IOException;
This class is a general class of exceptions generated by failed or interrupted I / O operations.

import java.net.Socket;
This class works to listen to connections that have occurred and ready to receive requests from other processes.

public class Client {
declaration for the class client

public static void main(String[] args)throws IOException {
public static void main is an element that must exist in java programming language

Socket sock=new Socket("localhost", 6066);
This is the declaration of a new object named "sock"

DataInputStream in= new DataInputStream(sock.getInputStream());
This is the shortcut of objects in the DatasInputStream class

System.out.println(in.readUTF());
Command to display the output to the monitor

DataOutputStream out =new DataOutputStream(sock.getOutputStream());
This is the creation of the output object in the DataInputStream class

out.writeUTF("what is youre name");
this is the command to display the text on the output
sock.close();

After creating the client program we will create a server program, create a file with the name Server.java.
then type the program below in Server.java file

package clientserver;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;3
public class Server {
    public static void main(String[] args) throws IOException{
       ServerSocket serverSock=new ServerSocket(6066);
       Socket Sock=serverSock .accept();
       DataOutputStream out =new DataOutputStream(Sock.getOutputStream());
       out.writeUTF("my name is lapulga");
       DataInputStream in= new DataInputStream(Sock.getInputStream());
        System.out.println(in.readUTF());
       Sock.close(); }}

the difference between the client program and the server program is on the syntaxSocket Sock=serverSock .accept(); which serves to receive requests from the client.
after we create both programs then we try to run both programs as shown below.
run both.
then we will see the output.

client output:

server output:

application using this method:

work principle

this method serves to connect between the client with the server on the program above shows that we try to send a message to the server and then the server answered. this method is very much used in chatingan applications such as yahoo mesengger and others.