Input from user in arraylist

[smitesh]

Hi friends
I m very new for java and i m reading collections right now. I m writing data into a text file and then transfering it in an arraylist. I want the reverse of it, which i am trying n hopefully i will get the soln also but the main problem is that i want to enter the data from user into an array list which will be shown in the text file and vice versa.. Plz help me

This i have done so far..

package comp;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
 
public class ProcessStudent {
 
 
    public static void main(String[] args){
        ArrayList<Student> studentList=new ArrayList<Student>();
        BufferedReader max;
 
        Student student1=new Student("Kamal","Mindtree",25);
                   Student student2=new Student("Smitesh","Accenture",23);
        Student student3=new Student("Sudish","Oracle",29);
 
        studentList.add(student1);
        studentList.add(student2);
        studentList.add(student3);
 
        File file=new File("C:/std1.txt");
        FileOutputStream fos=null;
        FileInputStream fis=null;
        ObjectOutputStream oos=null;
        ObjectInputStream ois=null;
 
        try{             
            fos=new FileOutputStream(file);
            oos=new ObjectOutputStream(fos);
            oos.writeObject(studentList);
 
            fis=new FileInputStream(file);
            ois=new ObjectInputStream(fis);
            Object output=ois.readObject();
 
            ArrayList<Student> studentListDuplicate =(ArrayList) output;
            for(Student student: studentListDuplicate){
                System.out.println(student.toString());
            }
        }catch (IOException e) {
            e.printStackTrace(); 
        }catch(ClassNotFoundException c){
            c.printStackTrace();
        }
        finally{
            try{
                if(fos!=null){
                    fos.close();
                }
                if(fis!=null){
                    fis.close();
                }
                if(oos!=null){
                    oos.close();
                }
                if(ois!=null){
                    ois.close();
                }
            }catch(IOException e){
                e.printStackTrace();
            }
        }
    }
}

[madhoriya22]

Hi friends
I m very new for java and i m reading collections right now. I m writing data into a text file and then transfering it in an arraylist. I want the reverse of it, which i am trying n hopefully i will get the soln also but the main problem is that i want to enter the data from user into an array list which will be shown in the text file and vice versa.. Plz help me

This i have done so far..

Hi,
Always use code tags while posting code. Luk how nice ur code is luking now ...

package comp;
 
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
 
public class ProcessStudent {
 
 
    public static void main(String[] args){
        ArrayList<Student> studentList=new ArrayList<Student>();
        BufferedReader max;
 
        Student student1=new Student("Kamal","Mindtree",25);
     Student student2=new Student("Smitesh","Accenture",23);
        Student student3=new Student("Sudish","Oracle",29);
 
        studentList.add(student1);
        studentList.add(student2);
        studentList.add(student3);
 
        File file=new File("C:/std1.txt");
        FileOutputStream fos=null;
        FileInputStream fis=null;
        ObjectOutputStream oos=null;
        ObjectInputStream ois=null;
 
        try{             
            fos=new FileOutputStream(file);
            oos=new ObjectOutputStream(fos);
            oos.writeObject(studentList);
 
            fis=new FileInputStream(file);
            ois=new ObjectInputStream(fis);
            Object output=ois.readObject();
 
            ArrayList<Student> studentListDuplicate =(ArrayList) output;
            for(Student student: studentListDuplicate){
                System.out.println(student.toString());
            }
        }catch (IOException e) {
            e.printStackTrace(); 
        }catch(ClassNotFoundException c){
            c.printStackTrace();
        }
        finally{
            try{
                if(fos!=null){
                    fos.close();
                }
                if(fis!=null){
                    fis.close();
                }
                if(oos!=null){
                    oos.close();
                }
                if(ois!=null){
                    ois.close();
                }
            }catch(IOException e){
                e.printStackTrace();
            }
        }
    }
}

What the problem u are having in this code. I think U need to serialize this class.

[r035198x]

Hi friends
I m very new for java and i m reading collections right now. I m writing data into a text file and then transfering it in an arraylist. I want the reverse of it, which i am trying n hopefully i will get the soln also but the main problem is that i want to enter the data from user into an array list which will be shown in the text file and vice versa.. Plz help me

This i have done so far..

package comp;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;

public class ProcessStudent {


public static void main(String[] args){
ArrayList<Student> studentList=new ArrayList<Student>();
BufferedReader max;

Student student1=new Student("Kamal","Mindtree",25);
Student student2=new Student("Smitesh","Accenture",23);
Student student3=new Student("Sudish","Oracle",29);

studentList.add(student1);
studentList.add(student2);
studentList.add(student3);

File file=new File("C:/std1.txt");
FileOutputStream fos=null;
FileInputStream fis=null;
ObjectOutputStream oos=null;
ObjectInputStream ois=null;

try{
fos=new FileOutputStream(file);
oos=new ObjectOutputStream(fos);
oos.writeObject(studentList);

fis=new FileInputStream(file);
ois=new ObjectInputStream(fis);
Object output=ois.readObject();

ArrayList<Student> studentListDuplicate =(ArrayList) output;
for(Student student: studentListDuplicate){
System.out.println(student.toString());
}
}catch (IOException e) {
e.printStackTrace();
}catch(ClassNotFoundException c){
c.printStackTrace();
}
finally{
try{
if(fos!=null){
fos.close();
}
if(fis!=null){
fis.close();
}
if(oos!=null){
oos.close();
}
if(ois!=null){
ois.close();
}
}catch(IOException e){
e.printStackTrace();
}
}
}
}

1.) Please use code tags when posting code.
2.) The code you posted has nothing to do with what you described above.

[Nepomuk]

2.) The code you posted has nothing to do with what you described above.

I don't agree r035198x, it might well have to do with one problems described.

You want to read in data for an ArrayList? Do you mean the studentList?

Anyhow, first of all, create a function, which has the Data, you would like to enter manually later, creates whatever you want to add (e.g. a Student object) and then adds the new Data to you list. When you have that working, have a look at the "java.util.Scanner" class. That lets you read in data and work with it.

Greetings,
Nepomuk

[r035198x]

I don't agree r035198x, it might well have to do with one problems described.

You want to read in data for an ArrayList? Do you mean the studentList?

Anyhow, first of all, create a function, which has the Data, you would like to enter manually later, creates whatever you want to add (e.g. a Student object) and then adds the new Data to you list. When you have that working, have a look at the "java.util.Scanner" class. That lets you read in data and work with it.

Greetings,
Nepomuk

I expected the OP to post an attempt at reading data from the user.

@OP If you want the data to be human readable in the file then you need to write Strings to the file not serialized objects.