在Java中使用对象（实体）

Question

I'm new to java and I've developed a program that allows the user to enter his in- and outcome, and also to see a summary of both (second code sample).

I use text files to store the data (first sample). I'm using two text files per user, one for the income and one for the outcome.

Bonus //category
21 //amount
28/12/2015 //date
Salary
13
03/01/2016
Savings Deposit
33
03/01/2016

The following code sample sums up the in- and outcome of the user (Note: opnEsoda is a scanner):

try {
while (opnEsoda.hasNextLine());

               do //I read only the lines with the amounts from textfile
                        {
                            String[] entry = new String[3];

                            int x =0;
                            for (int i = 0; i < 3; i++)
                            {
                                if (opnEksoda.hasNextLine())
                                {
                                    // Trim removes leading or trailing whitespace.
                                    entry[i] = opnEksoda.nextLine().trim();

                                }

                            }
                           x = Integer.parseInt(entry[1]); // converts string numbers to int
                           sumeksoda += x ; // addition ... Amounts of the txt file 
                        }

              while (opnEksoda.hasNextLine());
                // information dialog that show the money spent and got.
                    JOptionPane.showMessageDialog(null,
                    "You got: "+sumesoda+" €",
                    "Your stats",
                    JOptionPane.INFORMATION_MESSAGE,icon);


            } catch (FileNotFoundException e) {
                System.out.println("COULD NOT READ FILE!!!");
            }

This will print: You got 67 €

My goal is to give out the money spent this week and this month. I also want to know the amount of money spent on each category (optional). What is the best way to do that?

Answer 1

To calculate the income for the current month, you must analyze entry[2] (the date) inside the loop, and sum up only those values whose month is the same.

At the beginning of your program, store the current date:

GregorianCalendar cal = new GregorianCalendar();
cal.setTime(new Date());                          // store the current date
int curYear  = cal.get(cal.YEAR );
int curMonth = cal.get(cal.MONTH);

Then, when reading the file, parse the date and compare the year and month:

cal.setTime(new SimpleDateFormat("dd/MM/yyyy").parse(entry[2]));   // parse the date
if( cal.get(cal.YEAR)==curYear && cal.get(cal.MONTH)==curMonth ){
    x = Integer.parseInt(entry[1]); // converts string numbers to int
    sumeksoda += x ; // addition ... Amounts of the txt file 
}

To calculate the income from each category , you must analyze entry[0] (the category). If the categories are known in advance, then simply create several distinct sum variables:

int sumeksodaSalary=0;
int sumeksodaBonus=0;

And then, inside the loop:

if("Salary".equals(entry[0])) sumeksodaSalary += x ;
if("Bonus" .equals(entry[0])) sumeksodaBonus  += x ;