I am writing a program for keeping track of library books. There is an object book that includes a title, sku number, price and quantity. All the books are stored in an Array List. I'm trying to serialize the books and add new books but every time a book is added the last is overwritten.
here is the code below to load objects from save
public static void readSave() {
File stockFile = new File("inventory.txt");
try {
if(!stockFile.createNewFile() && stockFile.length() != 0) {
ObjectInputStream objIn = new ObjectInputStream(new FileInputStream(stockFile));
int size = objIn.readInt();
for(int i = 0; i < size; i++) {
Book t = (Book) objIn.readObject();
bookList.add(t);
}
objIn.close();
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
here is my save method and it is set to save every time the program executes.
public static void save() {
File inventoryFile = new File("inventory.txt");
ObjectOutputStream objOut;
try {
objOut = new ObjectOutputStream(new FileOutputStream(inventoryFile));
objOut.writeInt(bookList.size());
Iterator<Book> i = bookList.iterator();
while(i.hasNext()){
objOut.writeObject(i.next());
}
objOut.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
below is my main method which calls these functions
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
readSave();
CampusBookWindow window = new CampusBookWindow();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
save();
}
});
}
My problem was when I hit the add book button I would not create a new book object for that item, but instead I was reassigning that last book object so the object last book object was erased from the bookList array list
Related
My program is supposed to search for a computer name and update the computer name value in the same instance of the GUI that it was searched in. If I launch the application and search for the computer name and hit search, it won't appear in the same instance. If I hit run again, the computer name I just searched for appears in the label in the new instance of the GUI.
So basically at the moment I have to launch a new instance of the GUI to see the updated computer name. Any help is appreciated. I've been stuck on this for a long time now.
Relevant Code:
try (BufferedReader br = new BufferedReader(new FileReader("resultofbatch.txt")))
{
final Pattern PATTERN = Pattern.compile("CN=([^,]+).*");
try {
while ((sCurrentLine = br.readLine()) != null) {
String[] tokens = PATTERN.split(","); //This will return you a array, containing the string array splitted by what you write inside it.
//should be in your case the split, since they are seperated by ","
// System.out.println(sCurrentLine);
CN = sCurrentLine.split("CN=",-1)[1].split(",",-1)[0];
System.out.println(CN);
testLabel.setText(CN);
}
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
} catch (IOException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MISControlPanel window = new MISControlPanel();
window.frame.setVisible(true);
//testLabel.setText(CN);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
You can view the full class here: http://pastebin.com/8hH1TMD3
I want to maintain database of users of a Bank for my project. I am able to save the number of users in one serializable file. But when I try to save the user to database it adds only the latest one to database.
Below is the sneak peak of code which writes the objects:
if(e.getSource()==submit) {
if(uFName != null && uLName != null && uInitialDeposit !=0) {
if(uAccountType=="Savings") {
Random randomGenerator = new Random();
//Gets the number of users from file if file exists
File f = new File(fileNameAdmin);
if(f.exists() && !f.isDirectory()) {
admin=db.readFromAdminDatabase();
}
u[admin.numberOfUsers]= new User();
u[admin.numberOfUsers].fName=uFName;
u[admin.numberOfUsers].lName=uLName;
u[admin.numberOfUsers].initalDeposit=uInitialDeposit;
u[admin.numberOfUsers].interestRate=uInterestRate;
u[admin.numberOfUsers].accountType="Saving";
u[admin.numberOfUsers].accountNumber=690000+admin.numberOfSavingsAccount;
//Generates a 4 digit random number which will be used as ATM pin
u[admin.numberOfUsers].atmPin=randomGenerator.nextInt(9999-1000)+1000;
//A savings account will be created
sa[admin.numberOfSavingsAccount]=new SavingsAccount(u[admin.numberOfUsers].accountNumber,u[admin.numberOfUsers].fName,u[admin.numberOfUsers].lName,
u[admin.numberOfUsers].initalDeposit,
u[admin.numberOfUsers].interestRate);
u[admin.numberOfUsers].sa=sa[admin.numberOfSavingsAccount];
System.out.println(u[admin.numberOfUsers].sa.balance);
JOptionPane.showMessageDialog(submit,"Congratulations! You are now a member of Symbiosis Bank."
+ "\nYour account number is "+u[admin.numberOfUsers].accountNumber
+" and your ATM Pin is "+u[admin.numberOfUsers].atmPin,"Account Created",JOptionPane.INFORMATION_MESSAGE);
try {
//for(int j = 0; j<admin.numberOfUsers; j++)
db.addUserToDatabase(u[admin.numberOfUsers]);
admin.numberOfSavingsAccount++;
admin.numberOfUsers++;
db.updateAdminDatabase(admin);
dispose();
setVisible(false);
//Welcome welcome = new Welcome();
//welcome.setVisible(true);
InitialInput back = new InitialInput();
back.setVisible(true);
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
The database class which has functions to write to database:
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
public class Database implements Serializable {
String fileName = System.getProperty("user.home")+"/db.ser";
String fileNameAdmin = System.getProperty("user.home")+"/admindb.ser";
public void addUserToDatabase(User u){
FileOutputStream fos;
try {
fos = new FileOutputStream(fileName);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(u);
oos.close();
}
catch(Exception e) {
e.printStackTrace();
}
}
#SuppressWarnings("finally")
public User readFromUserDatabase() {
FileInputStream fis;
User temp = null;
try {
fis = new FileInputStream(fileName);
ObjectInputStream ois = new ObjectInputStream(fis);
temp = (User)ois.readObject();
//System.out.println(temp.fName);
ois.close();
}
catch(Exception e) {
e.printStackTrace();
}
finally {
return temp;
}
}
public void updateAdminDatabase(Administrator admin) {
FileOutputStream fos;
try {
fos = new FileOutputStream(fileNameAdmin);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(admin);
oos.close();
}
catch(Exception e) {
e.printStackTrace();
}
}
#SuppressWarnings("finally")
public Administrator readFromAdminDatabase() {
FileInputStream fis;
Administrator temp = null;
try {
fis = new FileInputStream(fileNameAdmin);
ObjectInputStream ois = new ObjectInputStream(fis);
temp = (Administrator)ois.readObject();
//System.out.println(temp.fName);
ois.close();
}
catch(Exception e) {
e.printStackTrace();
}
finally {
return temp;
}
}
}
The code which is trying to read the database:
public void actionPerformed(ActionEvent e) {
if(e.getSource()==deposit) {
//Ask the amount to deposit
int userAmountToDeposit;
try {
for(int i = 0; i<=admin.numberOfUsers; i++) {
u[i] = db.readFromUserDatabase();
System.out.println(u[i].accountNumber);
}
for(int j =0; j<=admin.numberOfUsers; j++) {
if(u[j].accountNumber==userAccountNumber) {
if(u[j].atmPin==userPin) {
u[j].accountBalance=u[j].sa.balance;
u[j].sa.deposit(10);
u[j].accountBalance=u[j].sa.balance;
System.out.println(u[j].accountBalance);
}
}
}
}
Inorder to write and read multiple objects please try as below
Writing multiple object into List
WriteObject wo=new WriteObject(20, "Mohan");
WriteObject wo1=new WriteObject(21, "Mohanraj");
ArrayList<WriteObject> woi=new ArrayList<>();
try {
FileOutputStream fop=new FileOutputStream("c://object.ser");
ObjectOutputStream oos=new ObjectOutputStream(fop);
woi.add(wo);
woi.add(wo1);
oos.writeObject(woi);
} catch NotFoundException e) {
}
Reading all objects from file
try {
FileInputStream fis=new FileInputStream("C://object.ser");
ObjectInputStream ois=new ObjectInputStream(fis);
WriteObject wo=null;
WriteObject[] woj=new WriteObject[5];
ArrayList<WriteObject> woi=new ArrayList<>();
woi=(ArrayList<WriteObject>)ois.readObject();
for(int i=0;i<woi.size();i++){
woi.get(i).getvalues();
}
Here getvalues() is method present in Writeobject class. Follow the same mechanism for your code snippet
If you want to fix it rapidly, you can create a list and store first and foremost your objects in the list (may be ArrayList or List), and then you'll save this list on your file. That is the nice method. Make sure that your objects are serializable.
below, listeVoitures is a stactic variable that will contain all
object that i'm going to retrive from file.
public static void saveVehiculeInFile(ArrayList vehiculeList) {
ObjectOutputStream ous = null;
//ArrayList<Vehicule> listVehiculeToSave = new ArrayList<>();
try {
ous = new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream(new File("garage.txt"))));
try {
ous.writeObject(vehiculeList);
System.out.println("\t=====> Les vehicules *** ont été ajouter dans le garage.");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (ous != null) {
try {
ous.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
This method below is for retrive data from file
public static void readVehiculeFromFile() {
ObjectInputStream ins = null;
ArrayList<Vehicule> v = null;
try {
ins = new ObjectInputStream(new BufferedInputStream(new FileInputStream(new File("PoweredGarage.txt"))));
try {
v = (ArrayList<Vehicule>)ins.readObject();
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
for (Vehicule vehicule : v) {
listeVoitures.add(vehicule);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
if (ins != null) {
try {
ins.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
My program is basically a daily planner.
The schedule is saved in files by month and year by ObjectOutputStream. check
The schedule is arranged in an array by day. check
The schedule is retrieved by ObjectInputStream. This is where I have problems.
public class Calendar {
public String date;
public String[] schedule = new String[31];
Calendar(){
}
public String retrieve(int month, int day, int year) {
date = Integer.toString(month) + "-"+ Integer.toString(year ) + ".txt";
try {
ObjectInputStream input = new ObjectInputStream(new
FileInputStream(date));
input.readObject();
schedule = input;
//This is where I have the error obviously schedule is a string array and
//input is an ObjectInputStream so this wont work
input.close();
return schedule[day-1];
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "File not found";
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "IOException";
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "ClassNotFound";
}
}
public void save(int month, int day, int year, JTextArea entry) {
date = Integer.toString(month) + "-"+ Integer.toString(year ) + ".txt";
schedule[day-1]= entry.getText();
try {
ObjectOutputStream output = new ObjectOutputStream(new
FileOutputStream(date ));
output.writeObject(schedule);
output.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
The schedule will be displayed in a text area using something like
entry.setText(calendar.retrieve(month,day,year));
ObjectInputStream input = new ObjectInputStream(new FileInputStream(date));
OK.
input.readObject();
Pointless. This method returns the object that was read. You need to store it into a variable.
schedule = input;
Also pointless. input is an ObjectInputStream that you're about to close. Saving it in another variable is futile.
//This is where I have the error obviously schedule is a string array and
//input is an ObjectInputStream so this wont work
input.close();
It should be
schedule = (String[])input.readObject();
I'm trying to implement multiplayer in a game I've been writing, and I've gotten everything to successfully connect (I think..), but when I'm running it, there's an EOFException thrown by the client, and the object (an ArrayList) isn't successfully received.
Code for the server thread:
class ServerThread implements Runnable
{
ServerSocket server = null;
Socket controlSocket = null;
ObjectOutputStream outStream = null;
ObjectInputStream inStream = null;
#Override
public void run() {
setupConnection();
while(true){
sendObject(out.getStuff());
}
}
void setupConnection(){
Log.e("OUTPUTSHOOTER","init-connect");
try {
server = new ServerSocket(SERVERPORT);
Log.e("OUTPUTSHOOTER","server initiated port: "+SERVERPORT);
controlSocket = server.accept();
Log.e("OUTPUTSHOOTER","connected");
inStream = new ObjectInputStream(controlSocket.getInputStream());
outStream = new ObjectOutputStream(controlSocket.getOutputStream());
} catch (StreamCorruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.e("OUTPUTSHOOTER",server+" "+controlSocket+" "+inStream+" "+outStream);
}
public Object recieveObject(){
Object o = null;
try {
o = inStream.readObject();
} catch (OptionalDataException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return o;
}
public void sendObject(Object o)
{
try {
outStream.writeObject(o);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
And then the code for the client:
class ClientThread implements Runnable
{
Socket controlSocket = null;
ObjectOutputStream outStream = null;
ObjectInputStream inStream = null;
#Override
public void run() {
setupConnection();
while(true){
Log.e("OUTPUTSHOOTER","recieving");
Object in = recieveObject();
if(in!= null && in instanceof ArrayList)
{
Log.e("OUTPUTSHOOTER","loading");
out.load((ArrayList<UniverseObject>)in);
}
}
}
void setupConnection(){
Log.e("OUTPUTSHOOTER","ip: "+SERVERIP);
while(controlSocket == null) {
try {
controlSocket = new Socket(SERVERIP,SERVERPORT);
Log.e("OUTPUTSHOOTER","socket connected");
} catch (IOException e) {
e.printStackTrace();
}
}
try {
Log.e("OUTPUTSHOOTER","attempting streams");
outStream = new ObjectOutputStream(controlSocket.getOutputStream());
Log.e("OUTPUTSHOOTER","output working");
inStream = new ObjectInputStream(controlSocket.getInputStream());
Log.e("OUTPUTSHOOTER","streams connected");
} catch (StreamCorruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public Object recieveObject(){
Object o = null;
try {
o = inStream.readObject();
} catch (OptionalDataException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return o;
}
public void sendObject(Object o)
{
try {
outStream.writeObject(o);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
What does this mean? And perhaps more importantly, how can I fix it? Thanks in advance..
I don't see you closing your outputstream.
See this SO topic: Problem serializing and deserializing ArrayList
Turns out the server wasn't properly initiating it's input and output streams, even though its sockets were successful. Dunno why, but it only works if I started with the output stream first, then the input (?). Having some other really strange bugs, but at least the communication seems to work.. I'll look more in to them before posting here about it. Thanks guys!
I have 2 classes serial1 and serial 2. serial1 implements Serializable whereas serial2 does not.As per theory i should get an Exception for the following code, but it is working fine. why is it so ?
import java.io.*;
public class SerialTest {
public static void main(String args[]){
FileOutputStream fos=null;
ObjectOutputStream oos =null;
serial1 se = new serial1();
serial1 sd = null;
se.mets();
try {
fos= new FileOutputStream("serialtest");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
oos =new ObjectOutputStream(fos);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
oos.writeObject(se);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
FileInputStream fis=null;
ObjectInputStream ois = null;
try {
fis = new FileInputStream("serialtest");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
ois = new ObjectInputStream(fis);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
sd = (serial1) ois.readObject();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
sd.mets();
}
}
import java.io.Serializable;
public class serial1 implements Serializable{
/* public static void main(String []args){
serial1 ss = new serial1();
ss.mets();
}*/
public void mets(){
serial2 s2 = new serial2();
System.out.println( "serial 1 + mets");
s2.met1();
}
}
public class serial2 {
public void met1(){
System.out.println("serial2 + met1");
}
}
---------------------------*
The output is
serial 1 + mets
serial2 + met1
serial 1 + mets
serial2 + met1
You don't actually serialize serial2. Your mets method creates a local variable but as soon as the method returns it goes out of scope and becomes eligible for garbage collection.
If you had an instance variable of type serial2 inside serial1 then you would see an exception when you try to serialize (assuming it's a non-null value), but a local variable will not be a problem.
I don't see you ever serializing serial2