retrieving value from database in java
- by Akcire Atienza
I am making AGAIN another program that retrieves the inputted data/values of fields from the database I created. but this time, my inputted value will be coming from the JtextField I created. I wonder what's wrong in here bec when I'm running it the output is always null.
in this program i will convert the inputted value of my JTextField into int. here it is:
public class ButtonHandler implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
if(e.getSource() == extendB)
{
ExtensionForm extend = new ExtensionForm();
extend.setVisible(true);
}
else if(e.getSource()== searchB)
{
//get text from the textField
String guest = guestIDTF.getText();
//parse the string to integer for retrieving of data
int id = Integer.parseInt(guest);
GuestsInfo guestInfo = new GuestsInfo(id);
Room roomInfo = new Room(id);
String labels[] = {guestInfo.getFirstName()+" "+guestInfo.getLastName(),""+roomInfo.getRoomNo(),roomInfo.getRoomType(),guestInfo.getTime(),"11:00"}; for(int z = 0; z<labels.length; z++) { labelDisplay[z].setText(labels[z]); }
in my second class it retrieves the inputted values of fields from the database I created
here's the code:
import java.sql.*;
public class Room
{
private String roomType;
private int guestID, roomNo;
private Connection con;
private PreparedStatement statement;
public Room(){
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/3moronsdb","root","");
}
catch (Exception e) {
e.printStackTrace();
}
}
public Room(int guestsID)
{
this();
try{
statement = con.prepareStatement("SELECT * FROM guest WHERE guestID=?");
statement.setInt(1, guestID);
ResultSet rs = statement.executeQuery();
while(rs.next()){
this.guestID = rs.getInt(1);
this.roomType = rs.getString(2);
this.roomNo = rs.getInt(3);
}
}catch(Exception e){
System.out.print(e);
}
}
//Constructor for setting rate
public Room(String roomType, int roomNo)
{
this();
try
{
statement = con.prepareStatement("Insert into room(roomType, roomNo) values(?,?)");
statement.setString(1, roomType);
statement.setInt(2, roomNo);
statement.executeUpdate();
}
catch(Exception e)
{
e.printStackTrace();
return;
}
}
//getting roomType
public String getRoomType(){
return roomType;
}
//getting roomNo
public int getRoomNo(){
return roomNo;
}
//getting guestID
public int getGuestId(){
return guestID;
}
}
i already insert some values in my 3moronsdb which are ( 1, Classic , 103). here's my TEST main class:
public class TestMain {
public static void main(String [] a){
GuestsInfo guest = new GuestsInfo(1); //note that this instantiation is the other class which i just
ask the other day.. (http://stackoverflow.com/questions/12762835/retrieving-values-from-database-in-java)
Room rum = new Room(1);
System.out.print(rum.getRoomType()+" "+ guest.getFirstName());
}
}
when i'm running it it only gives me null output for the Room class but i am getting the output of the GuestsInfo class which is 'Ericka'. Can you help me guys? I know I ask this kind of problem yesterday but i really don't know what's wrong in here now..
