/** 添加表达式,匹配操作符 "<". */
 public Condition addLt(final ColumnField<?> columnField, String value) {
   return add(Restrict.lt(columnField.getFieldName(), value, ParamValuedType.STRING));
 }
 /** 添加表达式,匹配操作符 "<". */
 public Condition addLt(final String propertyName, long value) {
   return add(Restrict.lt(propertyName, value, ParamValuedType.LONG));
 }