code: public static Object getPrimitiveDefaultValue(Class<?> primitiveType) {
          if (boolean.class.equals(primitiveType)) {
              return false;
          } else if (byte.class.equals(primitiveType)) {
              return (byte) 0;
          } else if (char.class.equals(primitiveType)) {
              return '\0';
          } else if (short.class.equals(primitiveType)) {
              return (short) 0;
          } else if (int.class.equals(primitiveType)) {
              return 0;
          } else if (long.class.equals(primitiveType)) {
              return 0L;
          } else if (float.class.equals(primitiveType)) {
              return 0F;
          } else if (double.class.equals(primitiveType)) {
              return 0D;
          } else {
              return null;
          }
      }
docs: 取得primitive类型的默认值。
  
  @param primitiveType 基本类型
  @return 默认值