I use ObjectInput/Output to initialize the hashmap named temp and it put all entry of the hashmap called map that is initialized to new and then use OutputStream to save it in file formatting is .ser
this work perfectly...
import java.io.*;
import java.util.HashMap;
public class PlayerInfo implements Serializable {
ObjectOutputStream out;
ObjectInputStream in;
File userData =new File("path.ser");
HashMap map ;
HashMap temp;
private Integer ID;
String name ;
boolean isItNull =false;
public static void main(String[] args) {
new PlayerInfo();
}
PlayerInfo(){
try {
initializeHashMap();
}catch (Exception e){
e.printStackTrace();
}
}
#SuppressWarnings("unchecked")
private void initializeHashMap(){
try {
//initialize ObjectInputStream in same method when I use it and close it then
in =new ObjectInputStream(new FileInputStream(userData));
if (isItNull){
temp =new HashMap<Integer,PlayerInfo>();
}else {
map =new HashMap<Integer,PlayerInfo>();
temp = (HashMap<Integer, PlayerInfo>) in.readObject();
in.close();
}
}catch (Exception e){
isItNull =true;
initializeHashMap();
}
}
private void getInfo(){
System.out.println("Ok we are in get info so write your ID:-");
int id = 10;
}
#SuppressWarnings("unchecked")
private void createInfo()throws IOException{
//same here initialize ObjectOutputStreamin same method when I use it and close it then
out =new ObjectOutputStream(new FileOutputStream(userData));
System.out.println("Ok we are in create info so write your ID:-");
ID =10;
String scnS ="Mohammed";
System.out.println("Write your name");
map.put(ID,new PlayerInfo(scnS));
temp.putAll(map);
System.out.println("Saving....");
out.writeObject(temp);
out.close();
}
public PlayerInfo(String name){
this.name =name;
}
}
but this throw EFOException
import java.io.*;
import java.util.HashMap;
public class PlayerInfo implements Serializable {
ObjectOutputStream out;
ObjectInputStream in;
File userData =new File("path.ser");
HashMap map ;
HashMap temp;
private Integer ID;
String name ;
boolean isItNull =false;
public static void main(String[] args) {
new PlayerInfo();
}
PlayerInfo(){
try {
openTheOutPutObjectStreamer();
openTheInPutObjectStreamer();
initializeHashMap();
}catch (Exception e){
e.printStackTrace();
}
}
//here I initialize it in separated method
private void openTheOutPutObjectStreamer()throws IOException{
out =new ObjectOutputStream(new FileOutputStream(userData));
}
//same here I initialize it in separated method
private void openTheInPutObjectStreamer()throws IOException{
in =new ObjectInputStream(new FileInputStream(userData));
}
#SuppressWarnings("unchecked")
private void initializeHashMap(){
try {
if (isItNull){
temp =new HashMap<Integer,PlayerInfo>();
}else {
map =new HashMap<Integer,PlayerInfo>();
temp = (HashMap<Integer, PlayerInfo>) in.readObject();
in.close();
}
}catch (Exception e){
isItNull =true;
initializeHashMap();
}
}
#SuppressWarnings("unchecked")
private void createInfo()throws IOException{
System.out.println("Ok we are in create info so write your ID:-");
ID =10;
String scnS ="Mohammed";
System.out.println("Write your name");
map.put(ID,new PlayerInfo(scnS));
temp.putAll(map);
System.out.println("Saving....");
out.writeObject(temp);
out.close();
}
public PlayerInfo(String name){
this.name =name;
}
}
if you see it the difference is only separate the Object Input/Output to a method and call them
and I am sorry I am a newbie in this website
I don't know a lot about IO but it seems like I cant separate it to methods and call it?
The problem is that in your first code you (correctly) open an input stream uses it and then closes it before doing anything else to the same file but in your second code version you also open the output stream on the same file before having read it and that output stream puts the marker (where to read or write) at the end of the file so when you use your input stream you get an End of file error.
Changing you code to this should work
openTheInPutObjectStreamer();
initializeHashMap();
openTheOutPutObjectStreamer();
Related
I've pair the code down to the methods I am having a problem, with. It 'seems' to work until I try to load the file again, and it comes up with nothing in it. (I have not fully understood how to clear the ArrayList before performing the 2nd load, but that is for later).
I am sorry if this is hidden somewhere under some other nomenclature I also have not learned yet, but this is a project that is due tomorrow and I am at my wit's end.
import java.util.*;
import java.io.*;
public class MainATM3 {
public static ArrayList<ClientAccount> accounts = new ArrayList<ClientAccount>();
public static ClientAccount editBankAccount = new ClientAccount("placeholder",1234,1);;
public static void main(String[] args) {
// Create ATM account ArrayList
ArrayList<ClientAccount> accounts = new ArrayList<ClientAccount>();
// Get Account data from files
initialLoadATMAccounts(accounts);
System.out.println("Loaded "+accounts.size());
System.out.println("before Array "+(accounts.size()));
accounts.add(0,new ClientAccount("Jess",500,1830));
accounts.add(1,new ClientAccount("Mary",1111.11,7890));
System.out.println("after Array "+(accounts.size()));
saveATMAccounts(accounts);
System.out.println("saved "+(accounts.size()));
initialLoadATMAccounts(accounts);
System.out.println("Loaded "+accounts.size());
System.out.println("Logged Out");
}
// Save ArrayList of ATM Objects //call by: saveATMAccounts(accounts);
public static void saveATMAccounts(ArrayList<ClientAccount> saveAccounts) {
FileOutputStream fout = null;
ObjectOutputStream oos = null;
try{
fout=new FileOutputStream("ATMAccounts.sav");
oos = new ObjectOutputStream(fout);
oos.writeObject(accounts);
System.out.println("objects written "+(accounts.size()));
} catch (Exception ex) {
ex.printStackTrace();
} finally {
if (fout != null) {
try {
fout.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (oos != null) {
try {
oos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
// INITIAL Load ArrayList of ATM Objects //call by: initialLoadATMAccounts(accounts);
public static void initialLoadATMAccounts(ArrayList<ClientAccount> loadAccounts){
FileInputStream fIS = null;
ObjectInputStream oIS = null;
try{
fIS=new FileInputStream("ATMAccounts.sav");
oIS = new ObjectInputStream(fIS);
ArrayList<ClientAccount> loadAccounts = (ArrayList<ClientAccount>) oIS.readObject();
oIS.close();
fIS.close();
}
catch(Exception exc){
exc.printStackTrace();
}
}
}
import java.io.Serializable;
public class ClientAccount implements Serializable {
public String accountName;
public double accountBalance;
public int accountPIN;
public ClientAccount(String accountName, double accountBalance, int accountPIN){
this.accountName=accountName;
this.accountBalance=accountBalance;
this.accountPIN=accountPIN;
}
// Account Name Methods
public String getAccountName() {
return accountName;
}
public void setAccountName(String name) {
accountName = name;
}
// Account Balance Methods
public double getAccountBalance() {
return accountBalance;
}
public void setAccountBalance(double balance) {
accountBalance = balance;
}
// PIN Methods
public int getAccountPIN() {
return accountPIN;
}
public void setAccountPIN(int newPIN) {
accountPIN = newPIN;
}
}
Instead of passing the desired array to initialLoadATMAccounts as param you should return the new, loaded array:
public static List<ClientAccount> initialLoadATMAccounts(){
FileInputStream fIS = null;
ObjectInputStream oIS = null;
try{
fIS=new FileInputStream("ATMAccounts.sav");
oIS = new ObjectInputStream(fIS);
ArrayList<ClientAccount> loadAccounts = (ArrayList<ClientAccount>) oIS.readObject();
oIS.close();
fIS.close();
return loadAccounts;
}
catch(Exception exc){
exc.printStackTrace();
}
}
BTW: A IDE like eclipse would have issued a warning where you overwrite the param loadAccounts.
So guys i need some help. I have a class Book and i want to save my books object to a Stream and then read this Stream file so i can search my objects from there. I have written my code but it gives me some errors and i can figure out how to print my books values .
So this is my Book class
public class Book {
private Date arr;
private Date depp;
private Type room;
private boolean breakfast = false;
private Person data;
private ObjectOutputStream out;
public Book(String name, String surename, String phone,Date arr, Date depp, Type room, boolean breakfast) {
data = new Person(name,surename,phone);
this.arr = arr;
this.depp = depp;
this.room = room;
this.breakfast = breakfast;
}
public void writeObjToFile(){//here i save my object to stream it gives me error, i call this method after i create my book object to main
try{
out = new ObjectOutputStream(new FileOutputStream("books.txt"));
out.writeObject(this);
}
catch(FileNotFoundException e){
System.err.println("File not Found");
e.printStackTrace();
}catch(IOException e){
System.err.println("IOException");
e.printStackTrace();}
}
}
and this is my Search class :
public class Search {
private FileInputStream fis=null;
private String filename;
public Search(String filename){
this.filename = filename;
File file = new File(filename);
try {
fis = new FileInputStream(file);
System.out.println("Total file size to read (in bytes) : "
+ fis.available());
int content;
while ((content = fis.read()) != -1) {
// convert to char and display it
System.out.print((char) content);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (fis != null)
fis.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
Book should implement Serializable
Check the API
https://docs.oracle.com/javase/7/docs/api/java/io/ObjectOutputStream.html#writeObject%28java.lang.Object%29
Also, remove the out member from Book class because it's not Serializable either.
I have created an object that i then added into an ArrayList. I then saved this arraylist into a .dat file using ObjectOutputStream. I know that the object has been created correctly because the next screen in the program loads directly from the object and the object can be read correctly from the file afterwards. The issue I am running into is that it appears that the object is saving, but it is not willing to be edited. Instead of editing the object in the arraylist, it is creating a new object and saving it again each time.
The code below shows the save function that is performed every time someone finishes the last screen. I am trying to make it so it will check to see if the student exists already in the array, and if so just edit the object. If the student doesn't exist, I want it to take selectedStudent (the object used for all GUI functions) and add it to the array "students" and write the array to the file, overwriting all previous data.
#SuppressWarnings("unchecked")
public static void saveNew() throws ClassNotFoundException, IOException{
int exists = -1;
try{
FileInputStream fis = new FileInputStream("records.dat");
ObjectInputStream in = new ObjectInputStream(fis);
students = (ArrayList<Student>) in.readObject();
in.close();
fis.close();
}
catch(IOException e){
e.printStackTrace();
}
try{
FileOutputStream fos = new FileOutputStream("records.dat", false);
ObjectOutputStream out = new ObjectOutputStream(fos);
for(int i = 0; i<students.size(); i++){
if(students.get(i).getID().equals(selectedStudent.getID())){
exists = i;
}
}
if(exists<0){
students.add(selectedStudent);
}
else{
students.set(i, selectedStudent);
}
out.writeObject(students);
out.close();
}
catch(IOException e){
e.printStackTrace();
}
}
Edit: I noticed that the variable exists was not being used to search for the object which was mistake number one, but I still have the issue where the saved object will not be changed until the method is called a second time. It seems to find it when it is run again, but when it is run the first time it will just create a new student with the edited name.
For example, the first student is created and saved. A second student is the created and saved. When the second student is being edited (without closing the program and restarting) it will, instead of editing the object in the file, create a new student object with the same information directly below the first. If the edit function is run a second time, the second student file is edited correctly but leaves the first as it was.
For a start I would edit these lines
if(students.get(i).getID().equals(selectedStudent.getID())){
exists = i;
}
to
if(students.get(i).getID().equals(selectedStudent.getID())){
System.out.println ("Got it");
exists = i;
break;
}
just to make sure it is working.
Also, you want to change the use of i to exists
else{
students.set(i, selectedStudent); // change to exists
}
I think you must check your variables (if you're reusing any) and initialization code.
The snippet you've posted seems to be fine, so I can't find the error on it.
Here goes a quite similar code that works. I hope it helps.
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
public class Persistence {
public static void main(String[] args) throws Exception {
File f = new File("records.dat");
// f.delete();
if (!f.exists()){
f.createNewFile();
}
Persistence p = new Persistence();
if (p.peek() == null){
p.init(); //persist an empty list
}
p.saveNew(new Student("ID1","Some Value")); //must insert
p.saveNew(new Student("ID1","Some Other Value")); //must edit
p.saveNew(new Student("ID2","Some Value")); //must insert
ArrayList<Student> list = p.peek();
System.out.println(list);
}
private void save(ArrayList<Student> list) throws Exception{
FileOutputStream fos = new FileOutputStream("records.dat",false);//don't append
ObjectOutputStream out = new ObjectOutputStream(fos);
out.writeObject(list);
out.flush();
out.close();
fos.close();
}
private void init() throws Exception{
save(new ArrayList<Student>());
}
private ArrayList<Student> peek() throws Exception{
FileInputStream fis = new FileInputStream("records.dat");
try{
ObjectInputStream in = new ObjectInputStream(fis);
ArrayList<Student> students = (ArrayList<Student>) in.readObject();
return students;
}catch(EOFException eof){
return null;
}finally{
fis.close();
}
}
public void saveNew(Student s) throws Exception {
ArrayList<Student> students = peek();
int editIndex = -1;
for(int i=0;i<students.size();i++){
if (students.get(i).getID().equals(s.getID())){
editIndex = i;
break;
}
}
if (editIndex != -1){
students.set(editIndex, s); //replace
}else{
students.add(s); //add
}
save(students);
}
}
where
import java.io.Serializable;
public class Student implements Serializable{
private static final long serialVersionUID = 1L;
private String ID;
private String s;
public Student(String ID, String s) {
this.ID = ID;
this.s = s;
}
public String getID() {
return ID;
}
public void setID(String iD) {
ID = iD;
}
public String getS() {
return s;
}
public void setS(String s) {
this.s = s;
}
#Override
public String toString() {
return "Student [ID=" + ID + ", s=" + s + "]";
}
}
This is my first time i try objects serializing.
My problem is that when i call for saving new objects(Reminder.java objects) it saves them in the hash map but when i load it gives me the properties of the last saved object.
So my question is:
1.Saving - How do i "append" objects to a file ?
2.Loading - how to iterate through them and get the right object (using the key class type MyDateClass)
. Example will be welcomed. Thank you.
public void save(MyDateClass chosenDate, String string){
System.out.println("Trying to save");
reminderMap.put(chosenDate, string);
//serializing an object :
this.dateReminder = chosenDate;
this.reminder = string;
try
{
FileOutputStream fileOut =
new FileOutputStream("/tmp/reminder.ser");
ObjectOutputStream out = new ObjectOutputStream(fileOut);
out.writeObject(this);
out.close();
fileOut.close();
System.out.printf("Serialized data is saved in /tmp/reminder.ser. ");
}catch(IOException i)
{
i.printStackTrace();
}
}
public String Load(MyDateClass chosenDate){
System.out.println("Trying to load");
this.reminder = reminderMap.get(chosenDate);
System.out.println(this.reminder);
// deserialize
Reminder e = null;
try
{
FileInputStream fileIn = new FileInputStream("/tmp/reminder.ser");
ObjectInputStream in = new ObjectInputStream(fileIn);
e = (Reminder) in.readObject();
in.close();
fileIn.close();
}catch(IOException i)
{
i.printStackTrace();
}catch(ClassNotFoundException c)
{
c.printStackTrace();
}
return e.reminder;
}
}
I did a demo and unit test for you, currently I use java.util.Date to substitute your SomeDate class .
update: 2013-12-31
I am not trying to make things complex,but I really feel it is my responsibility to not mislead others,so I try to fixed the code again.Currently, HashMap can't be append,please improve it.Thanks!
this code refactored from your code:
import java.io.*;
import java.util.*;
/**
* refactored by your code
* append object stream haven't realized,please help
* 2013-12-31
*/
public class Reminder implements Serializable {
public static void main(String[] args) {
//do some initialization
Reminder re = new Reminder();
re.put(new Date(System.currentTimeMillis()), "Hope it work!");
re.put(new Date(System.currentTimeMillis()+100), "it work!");
re.put(new Date(System.currentTimeMillis()+200), "Wake up!");
//save to file ,using append mode
String filpath = "/tmp/reminder.ser";
re.save(filpath,true);
//load from file and iterate the key-value pair
Reminder reLoad = Reminder.Load(filpath);
if(reLoad != null) {
Iterator<Map.Entry<Date,String>> it = reLoad.entrySet().iterator();
while(it.hasNext()) {
Map.Entry<Date,String> entry = it.next();
System.out.format("reminder: %tc---%s%n",entry.getKey(),entry.getValue());
}
}
}
public Set<Map.Entry<Date,String>> entrySet() {
return reminderMap.entrySet();
}
public void put(Date chosenDate, String string) {
reminderMap.put(chosenDate, string);
}
public String get(Date chosenDate) {
return reminderMap.get(chosenDate);
}
/**
* serializing an object
* #param filePath path to save file
* #param append indicate whether append or not
*/
public void save(String filePath,boolean append){
System.out.println("Trying to save");
try
{
ObjectOutputStream out = new ObjectOutputStream
( new FileOutputStream(filePath,append));
out.writeObject(this);
out.close();
System.out.printf("Serialized data is saved in "+filePath);
}catch(IOException e)
{
e.printStackTrace();
}
}
/**
* deserialize ,load from file and rebuild object
* #param filePath the path from where to load
* #return a new Object
*/
public static Reminder Load(String filePath) {
System.out.println("Trying to load");
Reminder reminder = null;
try
{
ObjectInputStream in = new ObjectInputStream
(new FileInputStream(filePath));
reminder = (Reminder) in.readObject();
in.close();
}catch(IOException | ClassNotFoundException e)
{
e.printStackTrace();
}
return reminder;
}
private static final long serialVersionUID = 1L;
private Map<Date,String> reminderMap = new HashMap<>();
}
This question already has an answer here:
StreamCorruptedException: invalid type code: AC
(1 answer)
Closed 5 years ago.
`I am new to java and getting StreamCorruptedException in the code below... In this code I am trying to read multiple objects from a file using ObjectInputStream... m not able to handle the StreamCorruptedException...the o/p I m getting is
File C098.txt already exists
Product ID:- P001
Description:- Book
Price:- Rs.200
Exception in thread "main" java.io.StreamCorruptedException: invalid type code:
AC
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1374)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:369)
at Utility.getProducts(Utility.java:57)
at Utility.main(Utility.java:23)
CODE:
import java.io.*;
import java.util.*;
class Product implements Serializable{
private static final long serialVersionUID = 1L;
String productId;
String desc;
String price;
public Product(String PId,String a_des,String a_price){
productId=PId;
desc=a_des;
price=a_price;
}
public String toString(){
return "Product ID:- "+productId+"\nDescription:- "+desc+"\nPrice:- "+price;
}
}
class Utility{
// Product objProduct;
public static void main(String args[]) throws Exception{
String cartId = "C098.txt";
Product objProduct = new Product("P001","Book","Rs.200");
addProductToCart(cartId,objProduct);
getProducts(cartId);
objProduct = new Product("P087","Laptop","Rs.45,500");
addProductToCart("C098.txt",objProduct);
getProducts(cartId);
}
public static void addProductToCart(String CId,Product p) throws Exception{
try{
boolean searchFile;
File objFile = new File(CId);
searchFile = objFile.exists();
if(searchFile)
System.out.println("File "+CId+" already exists");
else{
objFile.createNewFile();
System.out.println("File "+CId+" did not exist. It is now created");
}
FileOutputStream objFOS = new FileOutputStream(objFile,true);
ObjectOutputStream objO = new ObjectOutputStream(objFOS);
objO.writeObject(p);
objO.flush();
objO.close();
}catch(Exception e)
{
System.out.println("Exception Caught");
}
}
public static void getProducts(String CId) throws Exception{
Product objProduct1 = new Product("","","");
File objFile1 = new File(CId);
FileInputStream objFIS = new FileInputStream(objFile1);
ObjectInputStream objI = new ObjectInputStream(objFIS);
Object obj = null;
try{
while((obj=objI.readObject()) != null){
if (obj instanceof Product) {
System.out.println(((Product)obj).toString());
}
}
}catch (EOFException ex) { //This exception will be caught when EOF is reached
System.out.println("End of file reached.");
}finally {
//Close the ObjectInputStream
try{
if (objI != null)
objI.close();
}catch (IOException ex) {
ex.printStackTrace();
}
}
}
}`
The problem is because of header issue, You are appending to same file and while returning second object it throws exception because of headers issue. try to write object in different files, you can rid out of the problem.
SCE Thrown when control information that was read from an object stream violates internal consistency checks.
try
import java.io.*;
import java.util.*;
class Product implements Serializable{
private static final long serialVersionUID = 1L;
String productId;
String desc;
String price;
public Product(String PId,String a_des,String a_price){
productId=PId;
desc=a_des;
price=a_price;
}
public String toString(){
return "Product ID:- "+productId+"\nDescription:- "+desc+"\nPrice:- "+price;
}
// Product objProduct;
public static void main(String args[]) throws Exception{
String cartId = "C0982.txt";
Product objProduct = new Product("P001","Book","Rs.200");
addProductToCart(cartId,objProduct);
getProducts(cartId);
Product objProduct1 = new Product("P087","Laptop","Rs.45,500");
addProductToCart("C0981.txt",objProduct1);
getProducts("C0981.txt");
}
public static void addProductToCart(String CId,Product p) throws Exception{
try{
boolean searchFile;
File objFile = new File(CId);
searchFile = objFile.exists();
if(searchFile)
System.out.println("File "+CId+" already exists");
else{
objFile.createNewFile();
System.out.println("File "+CId+" did not exist. It is now created");
}
FileOutputStream objFOS = new FileOutputStream(objFile,true);
ObjectOutputStream objO = new ObjectOutputStream(objFOS);
objO.writeObject(p);
objO.flush();
objO.close();
}catch(Exception e)
{
System.out.println("Exception Caught");
}
}
public static void getProducts(String CId) throws Exception{
Product objProduct1 = new Product("","","");
File objFile1 = new File(CId);
FileInputStream objFIS = new FileInputStream(objFile1);
ObjectInputStream objI = new ObjectInputStream(objFIS);
Object obj = null;
try{
while((obj=objI.readObject()) != null){
if (obj instanceof Product) {
System.out.println(((Product)obj).toString());
}
}
}catch (EOFException ex) { //This exception will be caught when EOF is reached
System.out.println("End of file reached.");
}finally {
//Close the ObjectInputStream
try{
if (objI != null)
objI.close();
}catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
</pre>
You can't 'handle' it. You have to prevent it. It results from a design error such as using two ObjectOutputStreams on a stream that is read by a single ObjectInputStream, as you are doing here by appending to the file, or writing data other than objects and not reading it symmetrically.