高性能 Springboot 银行应用程序设计

Question

我试图在 springboot 中做一个涉及多线程的项目。

在银行应用程序中，我可以synchronized地进行doWithdrawal()等操作，以保持帐户的完整性，但是我无法弄清楚仅在特定帐户级别如何执行此操作。

由于不同账号的用户应该能够同时进行提现，用我当前的代码doWithdrawal()会让所有操作同步，不管账号如何。

目前，我在下面有非常基本的功能，我已将从一个帐户提款用作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提款，但是当同时从同一个账户多次提款时，只有这个过程应该是同步的。

所以我在这里寻找的是应用程序应该如何设计为具有这样的功能，我知道我们可以将@Async用于异步操作，但不确定这将如何适应同一帐户的提款应该是同步但不同的应该是异步的场景。

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

您可以在特定的"accountNum"上进行同步，而不是在整个方法上同步，如下所示：

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

这样，只有当帐号相同时，您才会同步。