我需要以下代码来同步运行。
这里是我的家庭控制器类的相关部分

/*
     * Pulls up beancoin blockchain on startup. 
     * 
     * If no beancoin exists, create one and populate it with initial values
     */
    @ModelAttribute("blockchain")
    public Blockchain addBlockchain() throws NoSuchAlgorithmException, InterruptedException {
        try {
            Blockchain blockchain = blockchainApp.getBlockchainService("beancoin");
            pnapp = new PubNubApp(blockchain);
            System.out.println("Pulling up your beancoin from our records");
            return blockchain;
        } catch (NoResultException e) {
            System.err.println("Creating new beancoin");
            Blockchain blockchain = blockchainApp.newBlockchainService("beancoin");

            // this seems to be going async and I need it to be sync (based on web render). What could be cause?
            Initializer.loadBC("beancoin");
            return blockchain;
        }
    }

上述方法在流方面运行良好，并正确地填充了本地数据库。但是，第一次在网页上显示的只是genesis\块，然后我必须启动和停止服务器，然后它会显示所有来自 Initializer.loadBC("beancoin"); 打电话。我不知道是什么原因导致它不同步。
这是你的名字 Initailizer.loadBC("beancoin"); 斯塔克，我觉得会有帮助的。
电话：

public static void loadBC(String nameOfBlockchain) {
        BlockchainService blockchainApp = new BlockchainService();
        blockchainApp.addBlockService(nameOfBlockchain, new String[] { "Dance", "The", "Quickstep" });
        blockchainApp.addBlockService(nameOfBlockchain, new String[] { "Dance", "The", "Waltz" });
        blockchainApp.addBlockService(nameOfBlockchain, new String[] { "Dance", "The", "Tango" });
        blockchainApp.addBlockService(nameOfBlockchain, new String[] { "Dance", "The", "Samba" });
        blockchainApp.addBlockService(nameOfBlockchain, new String[] { "Dance", "With", "Us", "America" });
    }

电话：

public boolean addBlockService(String name, String[] data) {
        return blockchainD.addBlock(name, data);
    }

电话：

@Override
    public boolean addBlock(String name, String[] data) {
        this.connect();
        Query query = em.createQuery("select b from Blockchain b where b.instance_name = :name");
        query.setParameter("name", name);
        Blockchain blockchain = (Blockchain) query.getSingleResult();
        try {
            em.getTransaction().begin();
            Block new_block = blockchain.add_block(data);
            em.persist(new_block);
            em.getTransaction().commit();
            this.disconnect();
            System.out.println("Returning true");
            return true;
        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return false;
        }
    }

我想这应该是你需要的全部信息了。
它没有抛出任何错误。它只是与页面不同步，因此如果我刷新所有数据库表（从头开始）并启动服务器，将显示以下内容：

只有这个。
然而，数据库有我需要的一切，如果我启动和停止服务器，并转到同一页，我得到这个（如预期的）。

这不仅仅是一个展示问题，尽管这很重要。我需要我的控制器是最新的，以便它可以与其他节点进行通信，并适当地报告链和更新链，如有必要。我的代码中似乎有某种东西隐式地告诉jvm它可以并发运行，或者在不同的线程上运行？？请帮我理解
编辑：当我把控制器代码改成这样时，它看起来仍然是异步的。我肯定给它足够的时间，所以一定有一个概念我不明白。

@ModelAttribute("blockchain")
    public Blockchain addBlockchain() throws NoSuchAlgorithmException, InterruptedException {
        try {
            Blockchain blockchain = blockchainApp.getBlockchainService("beancoin");
            pnapp = new PubNubApp(blockchain);
            System.out.println("Pulling up your beancoin from our records");
            return blockchain;
        } catch (NoResultException e) {
            System.err.println("Creating new beancoin");
            Blockchain blockchain = blockchainApp.newBlockchainService("beancoin");
            Thread.sleep(15000);
            // this seems to be going async and I need it to be sync (based on web render).
            // What could be cause?
            blockchainApp.addBlockService("beancoin", new String[] { "Dance", "The", "Quickstep" });
            blockchainApp.addBlockService("beancoin", new String[] { "Dance", "The", "Waltz" });
            blockchainApp.addBlockService("beancoin", new String[] { "Dance", "The", "Tango" });
            blockchainApp.addBlockService("beancoin", new String[] { "Dance", "The", "Samba" });
            blockchainApp.addBlockService("beancoin", new String[] { "Dance", "With", "Us", "America" });
            return blockchain;
        }
    }