HfClient的创建步骤有三个:

1. HFClient.createNewInstance()
2. HFClient.setCryptoSuite()
3. HFClient.setUserContext()

1. HFClient.createNewInstance()：主要是初始化了一个核心线程为0，最大线程为Max_Integer的线程池

这个方法调用了一下HFClient的私有构造方法

 /**
     * createNewInstance create a new instance of the HFClient
     *
     * @return client
     */
    public static HFClient createNewInstance() {
        return new HFClient();
    }

私有构造方法中是一个线程池的初始化

private HFClient() {

        executorService = new ThreadPoolExecutor(CLIENT_THREAD_EXECUTOR_COREPOOLSIZE, CLIENT_THREAD_EXECUTOR_MAXIMUMPOOLSIZE,
                CLIENT_THREAD_EXECUTOR_KEEPALIVETIME, CLIENT_THREAD_EXECUTOR_KEEPALIVETIMEUNIT,
                new SynchronousQueue<Runnable>(),
                r -> {
                    Thread t = threadFactory.newThread(r);
                    t.setDaemon(true);
                    return t;
                });
    }

线程池的配置信息在Config类里边，配置信息初始化在Config的私有构造方法中。SDK中的配置的逻辑是先从一个文件中进行读取配置，读取失败就加载默认配置。内个文件的路径是org.hyperledger.fabric.sdk.configuration.config.properties，但是找了半天也没找到内个配置文件。这个很让人头疼，我估计SDK就只是为了加载默认配置，而实际运行调用SDK的时候也正是跑的默认配置信息。主要代码如下

private Config() {
        File loadFile;
        FileInputStream configProps;
        try {
            从文件中加载默认配置
        } catch (IOException e) {
            打印错误日志
        } finally {
            如果文件加载配置出错，加载默认配置
        }
    }

2.HFClient.setCryptoSuite() 这个方法中只设置了一下cryptoSuite

   public void setCryptoSuite(CryptoSuite cryptoSuite) throws CryptoException, InvalidArgumentException {
        if (null == cryptoSuite) {
            throw new InvalidArgumentException("CryptoSuite paramter is null.");
        }
        if (this.cryptoSuite != null && cryptoSuite != this.cryptoSuite) {
            throw new InvalidArgumentException("CryptoSuite may only be set once.");

        }
        //        if (cryptoSuiteFactory == null) {
        //            cryptoSuiteFactory = cryptoSuite.getCryptoSuiteFactory();
        //        } else {
        //            if (cryptoSuiteFactory != cryptoSuite.getCryptoSuiteFactory()) {
        //                throw new InvalidArgumentException("CryptoSuite is not derivied from cryptosuite factory");
        //            }
        //        }

        this.cryptoSuite = cryptoSuite;
    }

3. HFClient.setUserContext() 这个方法首先对cryptoSuite 进行了非空校验，之后对用户证书进行校验

static void userContextCheck(User userContext) throws InvalidArgumentException {

        if (userContext == null) {
            throw new InvalidArgumentException("UserContext is null");
        }
        final String userName = userContext.getName();
        if (Utils.isNullOrEmpty(userName)) {
            throw new InvalidArgumentException("UserContext user's name missing.");
        }

        Enrollment enrollment = userContext.getEnrollment();
        if (enrollment == null) {
            throw new InvalidArgumentException(format("UserContext for user %s has no enrollment set.", userName));
        }
        if (enrollment instanceof X509Enrollment) {
            if (Utils.isNullOrEmpty(enrollment.getCert())) {
                throw new InvalidArgumentException(format("UserContext for user %s enrollment missing user certificate.", userName));
            }
            if (null == enrollment.getKey()) {
                throw new InvalidArgumentException(format("UserContext for user %s has Enrollment missing signing key", userName));
            }
        }

        if (Utils.isNullOrEmpty(userContext.getMspId())) {
            throw new InvalidArgumentException(format("UserContext for user %s  has user's MSPID missing.", userName));
        }

    }