code: public String process(String templateName, String templateSource, Map<String, Object> params) {
          try {
              Template template = new Template(templateName, templateSource, configuration);
              Writer writer = new StringWriter();
              template.process(params, writer);
              return writer.toString();
          } catch (Exception e) {
              throw new RuntimeException(e);
          }
      }
docs: 根据模板处理
  
  @param templateName
  @param templateSource
  @param params
  @return