code: @Override
      public String getParameter(String name) {
          if (this.charset.equalsIgnoreCase(this.originCharset)) {
              return super.getParameter(name);
          }
          String value = super.getParameter(name);
          if (value == null) {
              return null;
          }
          try {
              value = new String(value.getBytes(this.originCharset), this.charset);
          } catch (UnsupportedEncodingException e) {
              e.printStackTrace();
          }
  
          return value;
      }
docs: 对参数值进行编码