OUTBOUND SAP 作为服务消费方，获取请求数据的MESSAGE ID如下所示：

 DATA :  lr_req TYPE REF TO  zfi_si_interest,
         ls_req TYPE zfi_mt_interest_pr1,
         ls_rsp TYPE zfi_mt_interest_pro.

 "调用接口
  TRY.
      CREATE OBJECT lr_req.
      CALL METHOD lr_req->si_interest
        EXPORTING
          output = ls_req
        IMPORTING
          input  = ls_rsp.
    CATCH cx_sy_ref_is_initial INTO DATA(lo_initial).
      CALL METHOD lo_initial->get_text
        RECEIVING
          result = DATA(lv_error).

    CATCH cx_ai_system_fault INTO DATA(lo_fault).
      CALL METHOD lo_fault->get_text
        RECEIVING
          result = DATA(lv_error2).
  ENDTRY.

  "获取SXI_MONITOR 外发消息的MESSAGE_ID
  DATA: lo_protocol TYPE REF TO if_wsprotocol_message_id.
  IF lv_error = '' AND lv_error2 = ''.
    TRY.
        lo_protocol ?=  lr_req->get_protocol( if_wsprotocol=>message_id ).
        DATA(lv_pi_msgid_out_raw) = lo_protocol->get_message_id( ).
      CATCH cx_ai_system_fault.
    ENDTRY.
  ENDIF.