private static ServiceProvider getServiceProvider(Class<?> clazz) {
        ServiceProvider serviceProvider = serviceMap.get(clazz);
        if (serviceProvider == null) {
            getServiceProviders(clazz);
            serviceProvider = serviceMap.get(clazz);
        }
        return serviceProvider;
    }
@author Robert HG (254963746@qq.com)on 12/23/15.
lts-core/src/main/java/com/github/ltsopensource/core/spi/ServiceLoader.java