Creating a method from calling two classes in java [closed]

问题

I'm not sure which one of my methods that's not working. When i create accounts from addSavingsAccount everything is working fine, but when I want to print out the info from two classes it prints name and pNr but shows the first accountnumber to all clients. What's wrong with this?

//this works fine
public int addSavingsAccount(long pNr){ 

    for(int i = 0; i < customerlist.size(); i++)
    {
        if(customerlist.get(i).getPCode() == pNr)
        {
            Customer customer = customerlist.get(i);
            customer.addAccount(pNr);
            return account.getAccountId();
        }
    }
    return -1;
}


//but this don't
public String infoAccount(long pNr, int accountId)
{
    String info = "";
    for(Customer customer : customerlist) {
          if(customer.getPCode() == pNr) {
            this.customer = customer;
            ArrayList<SavingsAccount> accounts = customer.getAccount();
            for (SavingsAccount account : accounts) {
              this.account = account;
              if (account.getAccountId() == accountId){
                info = account.toString();
            }
            }
        }
     } 
    return info;
}

//this was my first try of printing out:
public String infoAccount(long pNr, int accountId)
{
    String info = "";
    for(Customer customer : customerlist)
    {
        if(pNr == customer.getPCode())
        {
            for(SavingsAccount account : accounts)
            {
                if(accountId == account.getAccountId())
                {
                    info = "Personnummer: " + pNr + "\nKontonummer: " + accountId
                    + "\nSaldo: " + amount + "\nRänta: " + SavingsAccount.RATE;
                }
            }
        } 
    }
    return info; 
}


//the methods in Customerclass
public void addAccount(long pNr){
    accounts.add(new SavingsAccount());
}

public ArrayList<SavingsAccount> getAccount(){
    return accounts;
}


//methods from SavingsAccount
public int getAccountId(){
    return accountCount++;
}

public String toString(){
    String infoAccount = "\tKontonr: " + accountId + "\tKontotyp: " + accounttype +
    "\nSaldo: " + balance + "\tRäntesats: " + RATE;
    return infoAccount;
}

回答1:

I am not sure I see enough code, but it looks like you're trying to set things up so that each account has an account ID. However, your getAccountId method is going to return a different value each time it's called, even when called on the same SavingsAccount, because it will increment a counter each time it's called.

What you need to do is to declare an instance member such as accountId in the SavingsAccount, and set it when a new SavingsAccount is created:

accountId = accountCount++;

That is the only place you want to use the ++. Then, getAccountId() would return the instance member, without incrementing anything.

来源：https://stackoverflow.com/questions/23523820/creating-a-method-from-calling-two-classes-in-java

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