高性能Spring Boot Banking应用程序设计

Question

我试图在春季启动时做一个涉及多线程的项目。

在银行应用程序中，我可以将doWithdrawal()等操作作为synchronizedin命令来维护帐户的完整性，但我无法弄清楚如何在特定帐户级别执行此操作。

由于具有不同帐号的用户应该能够同时执行提款，因此使用我当前的代码doWithdrawal()将使所有操作同步，而不管帐号如何。

目前我有非常基本的功能，我在一个帐户的提款用作synchronized操作。我想要一个场景，不同的账户持有人可以同时从自己的账户中退出，但是当多个账户同时从同一账户退出时，只有该流程应该是同步的。

所以我在这里寻找的是应用程序应该如何设计具有这样的功能，我知道我们可以使用@Async进行异步操作但不确定如何适用于同一帐户的提取应该同步但不同的情况异步。

Account.java

public class Account {

    int number ;
    float currentBalance ;
    float openingBalance ;
    String accountHolder ;
    String branch ;
    float rateOfInterest ;

    public int getNumber() {
        return number;
    }
    public void setNumber(int number) {
        this.number = number;
    }
    public float getCurrentBalance() {
        return currentBalance;
    }
    public void setCurrentBalance(float currentBalance) {
        this.currentBalance = currentBalance;
    }
    public float getOpeningBalance() {
        return openingBalance;
    }
    public void setOpeningBalance(float openingBalance) {
        this.openingBalance = openingBalance;
    }
    public String getAccountHolder() {
        return accountHolder;
    }
    public void setAccountHolder(String accountHolder) {
        this.accountHolder = accountHolder;
    }
    public String getBranch() {
        return branch;
    }
    public void setBranch(String branch) {
        this.branch = branch;
    }
    public float getRateOfInterest() {
        return rateOfInterest;
    }
    public void setRateOfInterest(float rateOfInterest) {
        this.rateOfInterest = rateOfInterest;
    }


}

App.java

public class App {

    public static void main(String[] args) {

        BankService.openAccount(1001);

        Thread2 t2 = new Thread2();
        Thread3 t3 = new Thread3();
        Thread4 t4 = new Thread4();

        t2.start();
        t3.start();
        t4.start();

    }
}

class Thread2 extends Thread {
    BankService bs = BankService.getInstance();
    public void run(){
        System.out.println("bs instrance is"+bs.hashCode());
        bs.doWithdrawal(200, 1001);
    }
}
class Thread3 extends Thread {
    BankService bs = BankService.getInstance();

    public void run(){
        System.out.println("bs instrance is"+bs.hashCode());

        bs.doWithdrawal(100, 1001);
    }
}
class Thread4 extends Thread {
    BankService bs = BankService.getInstance();
    public void run(){
        System.out.println("bs instrance is"+bs.hashCode());

        bs.doWithdrawal(100, 1001);
    }
}

BankService.java

import java.util.HashMap;
import java.util.Map;



public class BankService {


    private static BankService bankService ;

    private BankService(){

    }

    public static BankService getInstance(){

        if(bankService==null){
            return bankService = new BankService();
        }

        return bankService;
    }


    static Map<Integer,Account> accountMap = new HashMap<Integer, Account>();

    public void doDeposit(float amount,int accountNum){

        Account acc = accountMap.get(accountNum);
        acc.setCurrentBalance(acc.getCurrentBalance()+amount);
        System.out.println("made deposit");
        System.out.println("account :   "+acc.getNumber()+"   "+acc.getCurrentBalance());

    }


    public synchronized void doWithdrawal(float amount,int accountNum){

        Account acc = accountMap.get(accountNum);
        acc.setCurrentBalance(acc.getCurrentBalance()-amount);
        System.out.println("account :   "+acc.getNumber()+"   "+acc.getCurrentBalance());

    }

    public void checkBalance(int accountNumber){

    }

    public static void openAccount(int accnum){

        Account acc = new Account();
        acc.setCurrentBalance(2000);
        acc.setNumber(1001);

        accountMap.put(acc.getNumber(), acc);

        System.out.println("obj is"+accountMap);

    }
}

Answer 1

您可以按如下方式在特定的“accountNum”上同步，而不是在整个方法上进行同步：

 public void doWithdrawal(int accNum) {
    synchronized(accountMap.get(accNum)) {
        // now perform withdrawal
    }
 }

这样，只有在帐号相同时才会进行同步。