Question

我写了一些Java钱包生成代码，我用它来生成加密货币钱包。提供了代码，

public synchronized WalletInfo generateAddress(GenerateWallet generateWallet) {

        final WalletInfo walletInfo = new WalletInfo();

        String walletName = generateWallet.getWalletName();

        String currencyName = generateWallet.getCurrencyName();

        WalletInfo walletInfoDb = iWalletInfoDao.getWalletInfoWithWalletNameAndCurrency(walletName, currencyName);

        if (walletInfoDb == null && genWalletMap.get(walletName) == null) {

            String currency = currencyName.toUpperCase();

            if (currency.equals("BITCOIN")) {

                final WalletManager walletManager = WalletManager.setupWallet(walletName);

                walletManager.addWalletSetupCompletedListener((wallet) -> {

                    Address address = wallet.currentReceiveAddress();
                    WalletInfo newWallet = createWalletInfo(walletName, currencyName, address.toString());

                    // set the properties of the walletInfo
                    walletInfo.setId(newWallet.getId());
                    walletInfo.setName(newWallet.getName());
                    walletInfo.setAddress(newWallet.getAddress());
                    walletInfo.setCurrency(newWallet.getCurrency());

                    walletMangersMap.put(newWallet.getId(), walletManager);
                    genWalletMap.remove(walletName);
                });

                genWalletMap.put(walletName, walletManager);
                return walletInfo;
            } else if (currency.equals("ETHEREUM")) {
                return walletInfo;
            } else {
                return walletInfo;
            }
        }

        return walletInfo;
    }

当我使用cURL执行POST请求时，

curl -H "Content-Type: application/json" -X POST -d '{"walletName": "Florence8","currencyName":"Bitcoin"}' http://localhost:8080/rest/wallet/generateAddress

我得到null是返回，

{
  "id" : null,
  "name" : null,
  "address" : null,
  "currency" : null
}

实体生成后仍然存在于MySQL中。我一直在调试，这是有线的。调试不遵循从上到下的代码序列。调试的顺序就像，

我想说的是代码是否来到这一行 walletManager.addWalletSetupCompletedListener((wallet)，那么它应该执行里面的操作。

有任何建议如何在数据库中正确保留后恢复该实体？如果需要，我可以提供更多信息

更新

正如答案中所建议的，我使用CountDownLatch并解决问题

public synchronized WalletInfo generateAddress(GenerateWallet generateWallet) {

        CountDownLatch finshedSetup = new CountDownLatch(1);

    // some code 
}

终端输出

Answer 1

看起来你正处于竞争状态。您正在设置回调以填写walletInfo，但可能会在回调执行之前返回walletInfo。

某些类型的承诺或锁定在返回之前等待可能会有所帮助。例如：

public synchronized WalletInfo generateAddress(GenerateWallet generateWallet) {

        final WalletInfo walletInfo = new WalletInfo();

        String walletName = generateWallet.getWalletName();

        String currencyName = generateWallet.getCurrencyName();

        WalletInfo walletInfoDb = iWalletInfoDao.getWalletInfoWithWalletNameAndCurrency(walletName, currencyName);

        if (walletInfoDb == null && genWalletMap.get(walletName) == null) {

            String currency = currencyName.toUpperCase();

            if (currency.equals("BITCOIN")) {

                final WalletManager walletManager = WalletManager.setupWallet(walletName);
                CountDownLatch finishedSetup = new CountDownLatch(1);

                walletManager.addWalletSetupCompletedListener((wallet) -> {

                    Address address = wallet.currentReceiveAddress();
                    WalletInfo newWallet = createWalletInfo(walletName, currencyName, address.toString());

                    // set the properties of the walletInfo
                    walletInfo.setId(newWallet.getId());
                    walletInfo.setName(newWallet.getName());
                    walletInfo.setAddress(newWallet.getAddress());
                    walletInfo.setCurrency(newWallet.getCurrency());

                    walletMangersMap.put(newWallet.getId(), walletManager);
                    genWalletMap.remove(walletName);
                    finshedSetup.countDown();
                });

                genWalletMap.put(walletName, walletManager);
                finishedSetup.await();
                return walletInfo;
            } else if (currency.equals("ETHEREUM")) {
                return walletInfo;
            } else {
                return walletInfo;
            }
        }

        return walletInfo;
    }

POST请求在MySQL中持久存在，但返回null

1 个答案: