code: public static void generateWhereByPrimaryKeyTo(XmlElement element, List<IntrospectedColumn> primaryKeyColumns, String prefix) {
          StringBuilder sb = new StringBuilder();
          boolean and = false;
          for (IntrospectedColumn introspectedColumn : primaryKeyColumns) {
              sb.setLength(0);
              if (and) {
                  sb.append("  and ");
              } else {
                  sb.append("where ");
                  and = true;
              }
  
              sb.append(MyBatis3FormattingUtilities.getEscapedColumnName(introspectedColumn));
              sb.append(" = ");
              sb.append(MyBatis3FormattingUtilities.getParameterClause(introspectedColumn, prefix));
              element.addElement(new TextElement(sb.toString()));
          }
      }
docs: 生成 xxxByPrimaryKey 的where 语句
  @param element
  @param primaryKeyColumns
  @param prefix
  @return