我对OOP和Java很陌生并且有一个可能微不足道的问题，但我在网上找不到答案。
我正在使用Java进行标准的银行账户计划 - 一个有客户的计划，每个客户都有银行账户（一个客户可能有一个以上的银行账户！），我可以存款或取款。每个银行帐户都有一个唯一的号码（即使有人拥有多个银行帐户，每个银行帐户都有其唯一的号码）
我的代码编译，操作存款和取款工作正常。
问题如下 - 我不能将多个银行账户归属于客户，在我的计划中，客户可以只拥有一个银行且不超过一个银行账户。
我有3个班级 - 帐户，客户，BankMain。你可以在下面看到它们
public class Account {
private int balance;
private String NumAccount; // each bank account has a unique number
public Account(int money, String num) {
balance = money;
NumAccount = num;
}
public String printAccountNumber() {
return NumAccount;
}
// below are the methods for withdraw,deposit- they are working properly
}
班主任
public class Client {
private String name;// name of the client
private Account account;
// the account associated to the client. Probably I should change sth
// here
// but I don't know what
public Client(String nom, Compte c) {
name = nom;
account = c;
}
public void printName() {
System.out.println(
"Name: " + name
+ "\nAccount number: " + account.printAccountNumber()
+ "\nSolde: " + account.printBalance() + "\n"
);
}
}
和BankMain
public class BankMain {
public static void main(String[] args) {
Account account1 = new Account(1000, "11223A");
Account account2 = new Account(10000, "11111A");
Client client1 = new Client("George", account1);
Client client2 = new Client("Oliver", account2);
// now this is working correctly
client1.printName();
client2.ptintName();
/*
* The problem is that I don't know what to do if I want account1
* and account2 to belong both to client1. I tried Client client1 =
* new Client("George",account1); Client client1 = new
* Client("Oliver", account2); but got compilation error
*/
}
}
你知道我该如何解决这个问题吗？我该怎么办才能让多个银行账户关联到同一个客户？
提前致谢 乔治
答案 0 :(得分：1)
您可以为一个客户端设置多个帐户，以更改Client类中的数据类型。例如：
private Map<String, Account> accounts;
地图的密钥是帐号，而值是帐户本身。这样您就可以通过其唯一编号访问每个帐户。
（如果你不知道地图是什么，请检查this）
这也意味着您需要修改Client构造函数以接受多个帐户，或者添加新方法以将新帐户添加到Client。
答案 1 :(得分：1)
正如@ m0skit0建议的那样，使用地图或列表来保存Client类下的Account对象。
public class Client
{
private String name;//name of the client
private List<Account> accounts = new ArrayList<Account>();
public Client(String nom, Account c)
{
name = nom;
accounts.add (c);
}
public boolean addAccount (Account c)
{
return accounts.add (c);
}
public removeAccount (Account c)
{
final int accountIndex = accounts.indexOf (c);
if (accountIndex > 0)
{
accounts.remove (accountIndex);
return true;
}
return false;
}
public void printName()
{
System.out.println("Name: " + name);
System.out.println ("Total Accounts: " + accounts.size());
for (int i=0; i<accounts.size(); i++)
{
final Account a = accounts.get(i);
System.out.println ("\tAccount Number: " + a.printAccountNumber());
System.out.println ("\tAccount Balance: " + a.printBalance());
}
}
}
并在BankMain.java中使用它
Account account1 = new Account(1000,"11223A");
Account account2 = new Account(10000,"11111A");
Client client1 = new Client("George", account1);
client1.addAccount (account2);
client1.printName();
答案 2 :(得分：1)
查看此代码：
//Account
public class Account
{
private int balance;
private String accNo;
public Account(int money,String num) {
balance = money;
accNo = num;
}
public int getBalance() {
return balance;
}
public void setBalance(int balance) {
this.balance = balance;
}
public String getAccNo() {
return accNo;
}
public void setAccNo(String accNo) {
this.accNo = accNo;
}
}
//Client
import java.util.ArrayList;
import java.util.Collection;
public class Client
{
private String clientName;
private HashSet<Account> accounts;
public Client(String name)
{
this.clientName = name;
this.accounts = new HashSet<Account>();
}
public void addAccount(Account account) {
accounts.add(account);
}
public String getClientName() {
return clientName;
}
public void setClientName(String clientName) {
this.clientName = clientName;
}
public Collection<Account> getAccounts() {
return accounts;
}
public void setAccounts(HashSet<Account> accounts) {
this.accounts = accounts;
}
public void printAccountDetails() {
System.out.println("Account details :");
int counter= 0;
for(Account acc : accounts) {
counter ++;
System.out.println("Account details for Account '"+counter+"' :\n");
System.out.println("Account Number : "+ acc.getAccNo() +" Balance :" + acc.getBalance() );
}
}
}
// Bank class
public class BankMain {
public static void main(String[] args)
{
Account account1 = new Account(1000,"11223A");
Account account2 = new Account(10000,"11111A");
Client client = new Client("George");
client.addAccount(account1);
client.addAccount(account2);
client.printAccountDetails();
}
}
您可以在此处添加任意数量的帐户。
答案 3 :(得分：0)
而不是尝试再次重新定义client1和2，如：
Client client1 = new Client("George",account1);
Client client1 = new Client("Oliver", account2);
将这些对象重新定义为：
client1 = new Client("George",account1);
...
client1 = new Client("Oliver", account2);
但这样做，你可以在同一个账户上操作，即如果你现在做client1.withdraw，你将退出Oliver的账户而不是George。
您可以在地图中维护名称和帐户对象，而不是这样做，您可以随时获取该人的帐户名称。像：
Map<String, Account> nameAccountMap = ..
然后您将相应的帐户添加到其中：
nameAccountMap.put("Oliver", account2);
nameAccountMap.put("George",account1);
现在，如果您希望在Oliver拥有的帐户上运营，您可以通过以下方式进行操作：
nameAccountMap.get("Oliver").withdraw...
其他账户持有人的类似操作。
如果您希望将多个帐户与用户关联，您可以维护包含用户名称和帐户列表的地图，例如：
Map<String, List<Account>> nameAccountMap = ..
答案 4 :(得分：0)
不要在您的客户端类中使用单个Account，而是拥有Set<Account>以便拥有一对多的关系。确保帐户类已实施equals和hashcode。
public class Client
{
private String name;//name of the client
private Set<Account> accounts;
//the account associated to the client. Probably I should change sth here
// but I don't know what
public Client(String nom, Set<Account> c)
{
name = nom;
account = c;
}
public String getName()
{
return this.name;
}
public Set<Account> getAccounts()
{
return this.accounts;
}
public String toString()
{
...
// Return description of the Object state
}
}
public class Account
{
private int balance;
private String NumAccount; //each bank account has a unique number
public Account(int money,String num)
{
balance = money;
NumAccount = num;
}
public String getAccountNumber()
{
return NumAccount;
}
public boolean equals(..)
{
...
}
public int hashcode()
{
...
}
public String toString()
{
...
// Return description of the Object state
}
// below are the methods for withdraw,deposit- they are working properly
}