Writing double to file

Question

basically all i want to do is to write a double array in to a file and then read it back i actually want this to be a seperate class
The problem
First i enter 5 double all = 1; Then i read it back return all one, which is ok but then i try to write other number to the file it still returning all one
public class Storage extends JFrame{
    double aiw[];                           //This is use to take data from Ai class
    File weightfile3 = new File("weightdata3.dat");
    File weightfile5 = new File("weightdata5.dat");       
     File weightfile10 = new File("weightdata10.dat");
        //= new File("weightdata.dat"); //This create a file for saving the weight
  //  private RandomAccessFile file;
//    private JMenuItem newItem, updateItem,deleteItem,openItem,exitItem;
     Storage()
      //  weightfile3 = new File("weightdata3.dat");
        //weightfile5 = new File("weightdata5.dat");       
          //weightfile10 = new File("weightdata.dat");
    public void weightSave(double tempw[], int size)
    //This function save the data according to the information
     if(size == 3)
     File weightfile3 = new File("weightdata3.dat");
        try{//try to write data
            FileOutputStream file = new FileOutputStream(weightfile3, true);
            BufferedOutputStream buff = new BufferedOutputStream(file);//uses for buffering
            DataOutputStream weightdata = new DataOutputStream(buff);
            System.out.println("Inside weight function");//This is for debug//tested
            for(int i =0;i<6;i++){
                System.out.println(tempw);//uses for debug//tested
weightdata.writeDouble(tempw[i]);
//finish writing information into the file
weightdata.close();//close the file
catch(IOException e)//if failed
System.out.println("Error writing file :"+ e.toString());
     else if(size == 5)
     try{//try to write data
FileOutputStream file = new FileOutputStream(weightfile5, true);
BufferedOutputStream buff = new BufferedOutputStream(file);//uses for buffering
DataOutputStream weightdata = new DataOutputStream(buff);
//System.out.println("the weight that was saved");//This is for debug//tested
for(int i =0;i<10;i++){
System.out.println(tempw[i]);//uses for debug//tested
weightdata.writeDouble(tempw[i]);
//finish writing information into the file
weightdata.close();//close the file
catch(IOException e)//if failed
System.out.println("Error writing file :"+ e.toString());
     else
     try{//try to write data
FileOutputStream file = new FileOutputStream(weightfile10, true);
BufferedOutputStream buff = new BufferedOutputStream(file);//uses for buffering
DataOutputStream weightdata = new DataOutputStream(buff);
//System.out.println("the weight that was saved");//This is for debug//tested
for(int i =0;i<10;i++){
System.out.println(tempw[i]);//uses for debug//tested
weightdata.writeDouble(tempw[i]);
//finish writing information into the file
weightdata.close();//close the file
catch(IOException e)//if failed
System.out.println("Error writing file :"+ e.toString());
}//the end of save file
public double weightLoad(int nweight,int size)//this function require to know which weight need to be load
//this function should read from the file and return one double at a time
     if(size == 3)
double temp[] =new double[6];
double retral =0;
// System.out.println("int the weightLoad function");//uses for debug
try{
     FileInputStream file = new FileInputStream(weightfile3);
     BufferedInputStream buff = new BufferedInputStream(file);
     DataInputStream weightdata = new DataInputStream(buff);
// System.out.println("in the weightLoad function");//uses for debug
for(int i =0;i<6;i++) {
temp[i] = weightdata.readDouble();
//System.out.println(temp[i]);//uses for debug
          // System.out.println("read all the data");
     weightdata.close();
     }catch (IOException e) {System.out.println("Error reading from file"+e.toString());}
//System.out.println(temp);//This is for debug
for(int i=0;i<=nweight;i++)
retral = temp[i];
     System.out.println("The value that get return from load is : " + retral);
     return retral;
     else if(size == 5)
     double temp[] =new double[10];
double retral =0;
// System.out.println("int the weightLoad function");//uses for debug
try{
     FileInputStream file = new FileInputStream(weightfile5);
     BufferedInputStream buff = new BufferedInputStream(file);
     DataInputStream weightdata = new DataInputStream(buff);
System.out.println("in the weightLoad function");//uses for debug
for(int i =0;i<10;i++) {
temp[i] = weightdata.readDouble();
System.out.println(temp[i]);//uses for debug
          System.out.println("read all the data");
     //weightdata.close();
     }catch (IOException e) {System.out.println("Error reading from file"+e.toString());}
//System.out.println(temp);//This is for debug
for(int i=0;i<=nweight;i++)
retral = temp[i];
     System.out.println("The value that get return from load is : " + retral);
     return retral;
     else
     double temp[] =new double[10];
double retral =0;
// System.out.println("int the weightLoad function");//uses for debug
try{
     FileInputStream file = new FileInputStream(weightfile10);
     BufferedInputStream buff = new BufferedInputStream(file);
     DataInputStream weightdata = new DataInputStream(buff);
System.out.println("in the weightLoad function");//uses for debug
for(int i =0;i<10;i++) {
temp[i] = weightdata.readDouble();
//System.out.println(temp[i]);//uses for debug
     System.out.println("read all the data");
     //weightdata.close();
     }catch (IOException e) {System.out.println("Error reading from file"+e.toString());}
//System.out.println(temp);//This is for debug
for(int i=0;i<=nweight;i++)
retral = temp[i];
     System.out.println("The value that get return from load is : " + retral);
     return retral;

Answer 1

Your problem is caused by the way you save the data:
FileOutputStream file = new FileOutputStream(weightfile5, true);The argument "true" means that you append any data to the end of the file, rather than overwriting the current contents.
Your reader just reads the first data in the file - which are the ones that you put in initially. Thats why it is always returning all one.
To fix: remove the "true" from your call to FileOutputStream - it will then overwrite the current file.
Cheers,
evnafets