MAIN MENU BIODATA ASSIGNMENTS TUTORIALS EMAILS
Client Server Computing (TCT 2094)
TUTORIAL 2
(1 SERVER -MULTIPLE CLIENTS)
QUESTION:
Write a server for multiple clients. The client sends mortgage information (annual interest rate, number of years , and loan amount) to the server. The server computes monthly payment and total payment and sends them back to the client.
//and returns the result back to the client
import java.io.*;
import java.net.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Server extends JFrame {
//Text area for displaying contents
private JTextArea jta = new JTextArea();
public static void main(String[] args){
new Server();
}
public Server() {
//Place text area on the frame
getContentPane().setLayout(new BorderLayout());
getContentPane().add(new JScrollPane(jta),BorderLayout.CENTER);
setTitle("Server");
setSize(500,300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true); //It is necessary to show the frame here!
try{
//Create a server socket
ServerSocket serverSocket = new ServerSocket(8000);
jta.append("Server started at" +new Date()+ '\n');
//Listen for a connection request
Socket connectToClient = serverSocket.accept();
//Create data input and output streams
DataInputStream isFromClient = new DataInputStream(
connectToClient.getInputStream());
DataOutputStream osToClient = new DataOutputStream(
connectToClient.getOutputStream());
while (true) {
//Receive annual interest rate from the client
double annualInterestRate = isFromClient.readDouble();
//Receive number of years from the client
int numOfYears = isFromClient.readInt();
//Receive loan amount from the client
double loanAmount = isFromClient.readDouble();
//Obtain monthly interest rate
double monthlyInterestRate = annualInterestRate / 1200;
//Compute total payment
double totalPayment=(loanAmount*annualInterestRate/100*numOfYears)+loanAmount;
//Compute monthly payment
double monthlyPayment = totalPayment/(numOfYears*12);
//Send monthly payment back to the client
osToClient.writeDouble(monthlyPayment);
//Send total payment back to the client
osToClient.writeDouble(totalPayment);
jta.append("The Annual Interest Rate received from client is "+ annualInterestRate+'\n');
jta.append("The Number Of Years received from client is "+ numOfYears+'\n');
jta.append("The Loan Amount received from client is "+ loanAmount+'\n');
jta.append("The Monthly Payment is "+ monthlyPayment+'\n') ;
jta.append("The Total Payment is"+ totalPayment+'\n');
}
}
catch(IOException ex){
System.err.println(ex);
}
}
}
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//Client.java: The client sends the input to the server and receives
//result back from the server
import java.io.*;
import java.net.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Client extends JFrame implements ActionListener{
//Text field for receiving annual interest rate,number of years, loan amount
private JTextField jtfAnnualInterestRate = new JTextField();
private JTextField jtfNumOfYears = new JTextField();
private JTextField jtfLoanAmount = new JTextField();
private JButton jbtSubmit = new JButton("Submit");
//Text area for displaying contents
private JTextArea jta = new JTextArea();
//IO streams
DataOutputStream osToServer;
DataInputStream isFromServer;
public static void main(String[] args){
new Client();
}
public Client(){
JPanel p1 = new JPanel();
p1.setLayout(new GridLayout(3,1));
p1.add(new JLabel("Annual Interest Rate"));
p1.add(new JLabel("Number Of Years"));
p1.add(new JLabel("Loan Amount"));
Panel p2 = new Panel();
p2.setLayout(new GridLayout(3,1));
p2.add(jtfAnnualInterestRate);
p2.add(jtfNumOfYears);
p2.add(jtfLoanAmount);
JPanel p = new JPanel();
p.setLayout(new BorderLayout());
p.add(p1, BorderLayout.WEST);
p.add(p2,BorderLayout.CENTER);
p.add(jbtSubmit,BorderLayout.EAST);
jtfAnnualInterestRate.setHorizontalAlignment(JTextField.RIGHT);
jtfNumOfYears.setHorizontalAlignment(JTextField.RIGHT);
jtfLoanAmount.setHorizontalAlignment(JTextField.RIGHT);
getContentPane().setLayout(new BorderLayout());
getContentPane().add(p,BorderLayout.NORTH);
getContentPane().add(new JScrollPane(jta),BorderLayout.CENTER);
jbtSubmit.addActionListener(this); //Register listener
setTitle("Client");
setSize(500,300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
try{
//Create a socket to connect to the server
Socket connectToServer = new Socket("localhost",8000);
//Create an input stream to receive data from the server
isFromServer = new DataInputStream(connectToServer.getInputStream());
//Create an output stream to send data to the server
osToServer = new DataOutputStream(connectToServer.getOutputStream());
}
catch(IOException ex){
jta.append(ex.toString()+'\n');
}
}
public void actionPerformed(ActionEvent e){
String actionCommand = e.getActionCommand();
if(e.getSource() instanceof JButton){
try{
//Get the annual interest rate from the text field
double annualInterestRate =
Double.parseDouble(jtfAnnualInterestRate.getText().trim());
//Get the number of years from the text field
int numOfYears =
Integer.parseInt(jtfNumOfYears.getText());
//Get the loan amount from the text field
double loanAmount =
Double.parseDouble(jtfLoanAmount.getText().trim());
//Send the annual interest rate to the server
osToServer.writeDouble(annualInterestRate);
//Send the number of years to the server
osToServer.writeInt(numOfYears);
//Send the loan amount to the server
osToServer.writeDouble(loanAmount);
osToServer.flush();
//Get monthly payment from the server
double monthlyPayment = isFromServer.readDouble();
//Get total payment from the server
double totalPayment = isFromServer.readDouble();
//Display to the text area
jta.append("Annual Interest Rate: " + annualInterestRate +"\n");
jta.append("Number Of Years: " + numOfYears +"\n");
jta.append("Loan Amount: " + loanAmount +"\n");
jta.append("The Monthly Payment is: "+ monthlyPayment +"\n");
jta.append("The Total Payment is: "+ totalPayment +"\n");
}
catch(IOException ex){
System.err.println(ex);
}
}
}
}
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OUTPUT
