Having trouble with establishing connection between server and client for database - mysql

Question

Working on a project where I am trying to allow a user to enter an ISBN on the client (LibrarySystem), and when the button searchARL is pressed, it sends the ISBN to the server (ARLibrary). If the ISBN is present in the ARLibrary, it tells the client its available. If it doesn't exist in the ARLibrary database, it tells the client that the ISBN does not exist.
My problem is that I cannot seem to establish a connection between my server/client. I really have no idea what I am doing wrong but any help would be appreciated.
UPDATE: It seems like I DID get them to connect, but on line 164:
String resultFromARLibrary = (String) inputStream.readObject();
I am getting an exception that states:
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String
How do I go about fixing this?
Server code:
import java.net.ServerSocket;
import java.net.Socket;
import java.net.InetAddress;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.IOException;
import javax.swing.JOptionPane;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;
public class ARLibraryServer{
private ServerSocket serverSocket;
private Socket socket;
private ObjectInputStream inputStream;
private ObjectOutputStream outputStream;
private ResultSet result;
public ARLibraryServer(){
String URL = "jdbc:mysql://localhost/mulibrary?user=root&password=";
System.out.println("Server is running...");
try{
serverSocket = new ServerSocket(1098, 500);
while(true){
socket = serverSocket.accept();
inputStream = new ObjectInputStream(socket.getInputStream());
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(URL);
int isbn = (int) inputStream.readObject();
socket = new Socket(InetAddress.getByName("localhost"), 1097);
outputStream = new ObjectOutputStream(socket.getOutputStream());
String messageMU = "ISBN: " + isbn +
"\nAvailable at Arlington Library";
Statement search_arlingtonrs = con.createStatement();
String sql_statement = "select title from book where isbn = "+isbn+"";
result = search_arlingtonrs.executeQuery(sql_statement);
int iffound = 0;
while(result.next()) {
iffound = 1;
System.out.println(result.getString(1));
outputStream.writeObject("ISBN: " +isbn+
"\nTitle: " + result.getString(1) +
"\nAvailable at Arlington Library");
outputStream.flush();
}
if (iffound == 0){
String notfound = "ISBN: " +isbn+ "is not available at Arlington Library.";
outputStream.flush();
}
}
}
catch(ClassNotFoundException e){e.printStackTrace();}
catch(SQLException e){e.printStackTrace();}
catch(IOException e){e.printStackTrace();}
}
public static void main(String [] args){
new ARLibraryServer();
}
}
Client Code:
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.JTextField;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.JPanel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JOptionPane;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;
import java.net.Socket;
import java.net.InetAddress;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.io.ObjectInputStream;
//COMMANDS USED TO CREATE DATABASE:
//Applications/XAMPP/bin/mysql -u root
//show databases;
//create database mulibrary;
//use mulibrary;
//create table book (
//isbn char(9) primary key not null,
//title varchar(25));
public class LibrarySystem extends JFrame implements ActionListener{
private JLabel isbnLabel, titleLabel;
private JTextField isbnField, titleField;
private JButton addBook, searchMU, searchARL;
private JPanel centerPanel, centerPanel2, southPanel;
private ServerSocket serverSocket;
private Socket socket;
private ObjectInputStream inputStream;
private ObjectOutputStream outputStream;
private ResultSet result;
public LibrarySystem() {
isbnLabel = new JLabel("ISBN:");
titleLabel = new JLabel("Title:");
centerPanel = new JPanel();
centerPanel2 = new JPanel();
isbnField = new JTextField(15);
titleField = new JTextField(15);
centerPanel.add(isbnLabel);
centerPanel.add(isbnField);
centerPanel.add(titleLabel);
centerPanel.add(titleField);
centerPanel2.add(centerPanel);
centerPanel.setLayout(new GridLayout(2,2));
add(centerPanel2, BorderLayout.CENTER);
addBook = new JButton("Add New Book:");
addBook.addActionListener(this);
searchMU = new JButton("Search ISBN - MU Library");
searchMU.addActionListener(this);
searchARL = new JButton("Search ISBN - Arlington Library");
searchARL.addActionListener(this);
southPanel = new JPanel();
southPanel.add(addBook);
southPanel.add(searchMU);
southPanel.add(searchARL);
add(southPanel, BorderLayout.SOUTH);
setTitle("Library System");
setSize(600, 150);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent event) {
String URL = "jdbc:mysql://localhost/mulibrary?user=root&password=";
if(event.getSource()==addBook){
try{
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(URL);
String isbnint = isbnField.getText();
int isbn = Integer.parseInt(isbnint);
String title = titleField.getText();
String output = "The following book has been added to the Marymount Library:" +
"\nISBN: " + isbn +
"\nTitle: " + title;
String insert_add = "insert into book (isbn, title) values ('"+isbn+"','"+title+"')";
Statement add = con.createStatement();
add.execute(insert_add);
System.out.println("Insert Successful.");
JOptionPane.showMessageDialog(null, output);
}
catch(ClassNotFoundException e){
e.printStackTrace();
}
catch(SQLException e){
e.printStackTrace();
}
}
else if(event.getSource()==searchMU){
try{
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(URL);
String isbnint = isbnField.getText();
int isbn = Integer.parseInt(isbnint);
String title = titleField.getText();
Statement search_marymount = con.createStatement();
String sql_statement = "select title from book where isbn = "+isbn+"";
ResultSet result = search_marymount.executeQuery(sql_statement);
int lookfor = 0;
while(result.next()){
lookfor = 1;
System.out.println(result.getString(1));
JOptionPane.showMessageDialog(null, "ISBN: " + isbn + "\nTitle: " +
result.getString(1) + "\nAvailable at MU Library");
}
if(lookfor == 0){
String notfound = "ISBN: " + isbn + " is not available at MU Library.";
JOptionPane.showMessageDialog(null, notfound);
}
}
catch(ClassNotFoundException e){
e.printStackTrace();
}
catch(SQLException e){
e.printStackTrace();
}
}
else if(event.getSource()==searchARL){
try{
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(URL);
String isbnint = isbnField.getText();
int isbn = Integer.parseInt(isbnint);
String title = titleField.getText();
serverSocket = new ServerSocket(1098, 500);
while(true){
socket = new Socket(InetAddress.getByName("localhost"), 1098);
outputStream = new ObjectOutputStream(socket.getOutputStream());
outputStream.writeObject(isbn);
outputStream.flush();
System.out.println("Message has been sent.");
socket = serverSocket.accept();
inputStream = new ObjectInputStream(socket.getInputStream());
String resultFromARLibrary = (String) inputStream.readObject();
JOptionPane.showMessageDialog(null, resultFromARLibrary);
}
}
catch(ClassNotFoundException e){
e.printStackTrace();
}
catch(SQLException e){
e.printStackTrace();
}
catch (IOException e){
e.printStackTrace();
}
}
}
public static void main(String [] args){
LibrarySystem app = new LibrarySystem();
}
}

Answer 1

An attempt you can try is to replace localhost with 127.0.0.1