So I am new in programing and i adding a feature in my app which save all sharedpreference key in value in Device internal data folder by using fileoutputStream like this add all data in map and store in jsonobject
private String maptojson(){
Map<String, ?> map = prf.getAll();
JSONObject object = new JSONObject();
for (Map.Entry<String,?> entry : map.entrySet()){
try {
object.put( entry.getKey(), entry.getValue());
} catch (JSONException e) {
e.printStackTrace();
}
}
return object.toString();
}
Now Use FileOutputStream for write file in internal Storage "data'
public void backupSetting() {
Throwable th;
FileOutputStream fileOutputStream;
IOException e;
FileOutputStream fileOutputStream2 = null;
File externalStorageDirectory = Environment.getExternalStorageDirectory();
if (externalStorageDirectory.exists() && externalStorageDirectory.canWrite()) {
if (externalStorageDirectory.getUsableSpace() >= 1048576) {
File file = new File(externalStorageDirectory.toString() + "/data/MyApp/" + "MyAppSetting.ma");
try {
new File(file.getParent()).mkdirs();
file.createNewFile();
fileOutputStream = new FileOutputStream(file);
try {
fileOutputStream.write(maptojson().getBytes());
fileOutputStream.flush();
fileOutputStream.close();
if (fileOutputStream != null) {
try {
fileOutputStream.close();
} catch (IOException e2) {
e2.printStackTrace();
}
}
} catch (IOException e3) {
e = e3;
try {
e.printStackTrace();
if (fileOutputStream != null) {
}
} catch (Throwable th2) {
th = th2;
fileOutputStream2 = fileOutputStream;
if (fileOutputStream2 != null) {
try {
fileOutputStream2.close();
} catch (IOException e4) {
e4.printStackTrace();
throw th;
}
}
throw th;
}
}
} catch (IOException e5) {
e = e5;
fileOutputStream = null;
e.printStackTrace();
if (fileOutputStream != null) {
try {
fileOutputStream.close();
} catch (IOException e6) {
e6.printStackTrace();
}
}
} catch (Throwable th3) {
th = th3;
if (fileOutputStream2 != null) {
}
try {
throw th;
} catch (Throwable throwable) {
throwable.printStackTrace();
}
}
}
}
Now i want to add restore setting means restore setting by using that file "MyAppSetting.ma". I know i can do it by using FileInputStream but I don't understand how to do? please help if you could
Related
I have 3 objects written in the file. The program outputs these 3 objects and then this java.io.EOFException error.
writing to file:
try (ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream(file))) {
planes.sort(Comparator.comparingInt(plane -> plane.productionYear));
planes.forEach(plane -> {
try {
objectOutputStream.writeObject(plane);
} catch (IOException e) {
e.printStackTrace();
}
});
objectOutputStream.flush();
} catch (Exception e) {
e.printStackTrace();
}
reading the file:
try (ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream(file))) {
Object o;
while ((o = objectInputStream.readObject()) != null ){
if (o.getClass().getName().contains("Plane")) {
Plane plane = (Plane) o;
plane.productionYear = plane.productionYearCopy;
plane.speed = plane.speedCopy;
plane.engine = plane.engineCopy;
System.out.println(plane);
} else {
Ship ship = (Ship) o;
ship.productionYear = ship.productionYearCopy;
ship.speed = ship.speedCopy;
ship.engine = ship.engineCopy;
}
}
} catch (Exception e) {
e.printStackTrace();
}
public void writeUser() {
String userInfo;
FileOutputStream FOS= null;
UserConnector user = new UserConnector(); // this is other class receive data from user
user.modifyUserFromSignUpToDB(); // this method make all data as one string
userInfo = user.getUserInfo(); // get data from the class as string
try {
FOS = openFileOutput("usersInfo.txt", Context.MODE_APPEND);
FOS.write(userInfo.getBytes());
} catch (FileNotFoundException er) {
Log.e("malek", "cann't create file user");
} catch (IOException er) {
Log.e("malek", "cann't write to file user");
} finally {
try {
if (FOS != null) FOS.close();
} catch (IOException er) {
Log.e("malek", "cann't close file");
}
}
}
FOS always return as null, I try to use getApplicationContext(), this, classname.this and still have same problem
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();
}
}
}
}
I have following code :
// Read properties file.
Properties properties = new Properties();
try {
properties.load(new FileInputStream("filename.properties"));
} catch (FileNotFoundException e) {
system.out.println("FileNotFound");
}catch (IOException e) {
system.out.println("IOEXCeption");
}
Is it required to close the FileInputStream? If yes, how do I do that? I am getting a bad practice error in my code checklist . Asking it to put finally block.
You must the close the FileInputStream, as the Properties instance will not. From the Properties.load() javadoc:
The specified stream remains open after this method returns.
Store the FileInputStream in a separate variable, declared outside of the try and add a finally block that closes the FileInputStream if it was opened:
Properties properties = new Properties();
FileInputStream fis = null;
try {
fis = new FileInputStream("filename.properties");
properties.load(fis);
} catch (FileNotFoundException e) {
system.out.println("FileNotFound");
} catch (IOException e) {
system.out.println("IOEXCeption");
} finally {
if (null != fis)
{
try
{
fis.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
Use try-with-resources since Java 7:
final Properties properties = new Properties();
try (final FileInputStream fis =
new FileInputStream("filename.properties"))
{
properties.load(fis);
} catch (FileNotFoundException e) {
System.out.println("FileNotFound: " + e.getMessage());
} catch (IOException e) {
System.out.println("IOEXCeption: " + e.getMessage());
}
You should always close your streams, and doing it in the finally block is a good practice. The reason for this is that the finally block always gets executed, and you want to make sure that the stream is always closed, even if Something Bad happens.
FileInputStream inStream = null;
try {
inStream = new FileInputStream("filename.properties");
properties.load(inStream);
} catch (FileNotFoundException e) {
System.out.println("FileNotFound");
} catch (IOException e) {
System.out.println("IOEXCeption");
} finally {
try {
inStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
If you are using Java 7, this becomes much easier, since a new try-with syntax was introduced. Then you can write like this:
try(FileInputStream inStream = new FileInputStream("filename.properties")){
properties.load(inStream);
} catch (FileNotFoundException e) {
System.out.println("FileNotFound");
} catch (IOException e) {
System.out.println("IOEXCeption");
}
and the stream is closed automatically.
here is an example:
public class PropertiesHelper {
public static Properties loadFromFile(String file) throws IOException {
Properties properties = new Properties();
FileInputStream stream = new FileInputStream(file);
try {
properties.load(stream);
} finally {
stream.close();
}
return properties;
}
}
You can use Lombok #Cleanup to do it simply.
http://projectlombok.org/features/Cleanup.html
Properties properties = new Properties();
try {
#Cleanup FileInputStream myFis = new FileInputStream("filename.properties");
properties.load(myFis);
} catch (FileNotFoundException e) {
System.out.println("FileNotFound");
}catch (IOException e) {
System.out.println("IOEXCeption");
}
Or, only if your are using Java 7, there is the "try with resource" new feature.
http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html
Properties properties = new Properties();
try (FileInputStream myFis = new FileInputStream("filename.properties")) {
properties.load(myFis);
} catch (FileNotFoundException e) {
System.out.println("FileNotFound");
}catch (IOException e) {
System.out.println("IOEXCeption");
}
I'm looking for a place where are objects after serialization ? I would like to put serialized objects(created in another app) to my android project and then only load this files in my game. The problem is that I don't know where do I have to put this objects ? and even if I save object from android app it never saves in my project folder. My load and save functions for objects
public static void save(Context context, Map obj, String nazwa)
{
FileOutputStream str = null;
ObjectOutputStream objStr = null;
try {
str = context.openFileOutput(nazwa, Context.MODE_PRIVATE);
objStr = new ObjectOutputStream(str);
objStr.writeObject(obj);
} catch (FileNotFoundException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
} finally
{
try
{
if (objStr != null) objStr.close();
} catch (IOException e) {}
try
{
if (str != null) str.close();
} catch (IOException e) {}
}
}
public static Map load(Context context, String nameFile)
{
Map obj = null;
FileInputStream str_w = null;
ObjectInputStream obj_w = null;
try
{
str_w = context.openFileInput(nameFile);
obj_w = new ObjectInputStream(str_w);
obj = (Map) obj_w.readObject();
} catch (FileNotFoundException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
} catch (ClassNotFoundException e)
{
e.printStackTrace();
} finally
{
try
{
if (obj_w != null) obj_w.close();
} catch (IOException e) {}
try
{
if (str_w != null) str_w.close();
} catch (IOException e) {}
}
return obj;
}
If I copy my object file to /levels/ and use
final Map map2 = MapManager.load(this, "/levels/map1.lvl");
or
final Map map2 = MapManager.load(this, "levels/map1.lvl");
it never works
How should I do it ?
You're storing them as app private files (Context.MODE_PRIVATE) to a folder only the app has access to, so no other application will be able to access them.
I think the easiest way to store them so they can be shared between apps is to store them to the sdcard using:
Environment.getExternalStorageDir();
Be aware to store them as globally readable.