Java 如何获取类的实例？

我有以下代码

class driver{
        static BankAccount GetAccount(Customer customer, char c) {
            BankAccount accSrc = customer.S;
            // savings account
            if (c =='S') {
                accSrc = customer.S;
            // loan account
            } else if (c =='L') {
                accSrc = customer.L;
            // checking account
            } else if (c =='C') {
                accSrc = customer.C;
            // auto loan account
            } else if (c =='A') {
                accSrc = customer.A;
            }
            return accSrc;
        }
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            Customer forrest = new Customer("Forrest Gump", 1, "42 New Street, New York, New York"); // me
            Customer random = new Customer("Random Name", 2, "44 New Street, New York, New York"); // imaginary partner
            //try{
                String input = JOptionPane.showInputDialog("Please enter your transaction information: ");
                Scanner s = new Scanner(input);
                int id  = Integer.parseInt(s.next());
                char action = Character.toUpperCase((s.next().charAt(0)));
                char accSrc = ' ';
                char accDest = ' ';
                double amount = 0;

                if(action == 'T'){
                    amount = s.nextDouble();
                    accSrc = s.next().charAt(0);
                    accDest = s.next().charAt(0);
                }else if(action == 'G' || action == 'I'){
                    accSrc = s.next().charAt(0);
                }else{
                    //if D,W
                    amount = s.nextDouble();
                    accSrc = s.next().charAt(0);
                }

            //}catch (IOException e){

            //}
                if(id==1){
                    return forrest;
                }else if(id == 2){
                    return random;
                }
                BankAccount src = GetAccount(forrest,  accSrc);
                System.out.print(src.getOwner().name);
                if(action == 'T'){
                    BankAccount dst = GetAccount(forrest, accDest);
                    src.transfer(amount, dst);
.

    ..
    }

    class Customer{
        protected String name;
        protected int id;
        protected String address;
        protected BankAccount C = new BankAccount(id, this, 0);
        protected BankAccount S = new BankAccount(id, this, 0);
        protected BankAccount A = new BankAccount(id, this, 0);
        protected BankAccount L = new BankAccount(id, this, 0);
    ...
    }

---

当前im硬编码BankAccount

src=GetAccount（forrest，accSrc）如何继续编写代码，使其返回给定id号的客户实例（例如1个给定forrest返回，2个给定random返回）？
您需要将您的内容存储在a中，然后根据其索引检索列表项。
您需要将您的内容存储在a中，然后根据其索引检索列表项。
将您的类放入
映射中

 Map<Integer, Customer> classMap = new HashMap<Integer, Customer>();
 Customer forrest =
        new Customer("Forrest Stallings", 1, "42 New Street, New York, New York"); 
 classMap.put(1, forrest );

 Customer random = 
        new Customer("Random Name", 2, "44 New Street, New York, New York");
 classMap.put(2, random );

把你的课程放在地图上，例如

 Map<Integer, Customer> classMap = new HashMap<Integer, Customer>();
 Customer forrest =
        new Customer("Forrest Stallings", 1, "42 New Street, New York, New York"); 
 classMap.put(1, forrest );

 Customer random = 
        new Customer("Random Name", 2, "44 New Street, New York, New York");
 classMap.put(2, random );

更好

Customer customers[] = { forrest, random };

我可以使用
customer[id]
更好地调用实例

Customer customers[] = { forrest, random };

我可以使用
customer[id]
@user133466调用该实例。根据您的需求，可能会有更多的方法，但考虑到场景，这是最简单的方法，可以达到目的。@user133466有很多种方法，这确实是一种。您可以使用列表、数组、文件甚至数据库。事实上，如果您仍在硬编码，这是最简单的解决方案。@user133466根据您的需求，可能会有更多的解决方案，但鉴于该场景，这是最简单的解决方案，并且可以达到目的。@user133466有很多种方法，这确实是一种。您可以使用列表、数组、文件甚至数据库。事实上，如果你还在硬编码的话，这是最简单的解决方案。