code: public float getRequstURIPath(String prefix, float defvalue) {
          String val = getRequstURIPath(prefix, null);
          try {
              return val == null ? defvalue : Float.parseFloat(val);
          } catch (NumberFormatException e) {
              return defvalue;
          }
      }
docs: 获取请求URL分段中含prefix段的float值   <br>
  例如请求URL /pipes/record/query/point:40.0   <br>
  获取time参数: float point = request.getRequstURIPath("point:", 0.0f);
  
  @param prefix   prefix段前缀
  @param defvalue 默认float值
  
  @return float值