apollo-core/src/main/java/com/ctrip/framework/apollo/core/dto/ServiceDTO.java/ServiceDTO/toString
class ServiceDTO:  @Override
  public String toString() {
    final StringBuilder sb = new StringBuilder("ServiceDTO{");
    sb.append("appName='").append(appName).append('\'');
    sb.append(", instanceId='").append(instanceId).append('\'');
    sb.append(", homepageUrl='").append(homepageUrl).append('\'');
    sb.append('}');
    return sb.toString();
  }