code: private String getActualComponentType(String componentType) {
  
          if (componentType == null) {
              throw new IllegalArgumentException("参数不能为null.");
          }
  
          int lastIndex = componentType.lastIndexOf(ARRAY_PREFIX);
          if (lastIndex != -1) {
              StringBuilder sb = new StringBuilder();
              for (int i = 0; i < lastIndex + 1; i++) {
                  sb.append(ARRAY_PREFIX);
              }
              sb.append("L");
              sb.append(componentType.substring(lastIndex + 1));
              sb.append(";");
              return sb.toString();
          }
  
          return componentType;
      }
docs: 对于Object[]数组, 传入的componentType为[java.lang.Object, 但是Class.forName 需要的字符串是 [Ljava.lang.Object;
  如果不以'['开头, 直接返回, 否则拼接Class.forName需要的字符串格式
  @return