code: public ActiveEntity load() {
  		try {
  			final Entity result = db.get(this);
  			if(MapUtil.isNotEmpty(result)) {
  				this.putAll(result);
  			}
  		} catch (SQLException e) {
  			throw new DbRuntimeException(e);
  		}
  		return this;
  	}
docs: 根据Entity中现有字段条件从数据库中加载一个Entity对象
  
  @return this