前面几篇博客文章介绍 BAPI_ACC_DOCUMENT_POST 的使用，如果需要用代码完成类似 F-04 过账并清账的操作，可以顺序调用下面的三个函数：
- POSTING_INTERFACE_START- POSTING_INTERFACE_CLEARING- POSTING_INTERFACE_END
这三个函数在内部也是调用 BDC，但对于开发者来说，只需要给定参数，简化了编码的工作。
为了便于理解，假定我们需要对下面的会计凭证进行清账：
应付账款是未清项目，现在要对应付账款进行清账。先给出完整的代码，后面再对要点进行解释：
REPORT z_post_clearing.DEFINE populate_ftpost. clear ls_ftpost. ls_ftpost-stype = &1. ls_ftpost-count = &2. ls_ftpost-fnam = &3. ls_ftpost-fval = &4. append ls_ftpost to lt_ftpost.END-OF-DEFINITION.START-OF-SELECTION. PERFORM frm_post_clearing.FORM frm_post_clearing. " ftclear 是清账的数据的表参数 DATA: lt_ftclear TYPE STANDARD TABLE OF ftclear, ls_ftclear LIKE LINE OF lt_ftclear. " ftpost 是过账的抬头和行项目的表参数 DATA: lt_ftpost TYPE STANDARD TABLE OF ftpost, ls_ftpost LIKE LINE OF lt_ftpost. DATA: lt_blntab LIKE TABLE OF blntab WITH HEADER LINE, lt_fttax LIKE TABLE OF fttax WITH HEADER LINE. " populate ftclear table parameter CLEAR ls_ftclear. ls_ftclear-agkoa = 'K'. " k for vendor ls_ftclear-agbuk = 'Z900'. ls_ftclear-selfd = 'BELNR'. ls_ftclear-xnops = 'X'. ls_ftclear-selvon = '1900000001'. APPEND ls_ftclear TO lt_ftclear. " populate ftpost table paramter " 分为header和line item，line item按行填充 " 首先填写header (K) populate_ftpost 'K' 1 'BKPF-BUKRS' 'Z900'. " company code populate_ftpost 'K' 1 'BKPF-BLART' 'KA'. " document type populate_ftpost 'K' 1 'BKPF-BLDAT' sy-datum. " posting date populate_ftpost 'K' 1 'BKPF-BUDAT' sy-datum. populate_ftpost 'K' 1 'BKPF-WAERS' 'CNY'. " currency populate_ftpost 'K' 1 'BKPF-BKTXT' 'Clearing 1900000001'. " header text " 按行填写行项目的字段 (P) populate_ftpost 'P' 1 'RF05A-NEWBS' '50'. " posting key populate_ftpost 'P' 1 'BSEG-HKONT' '10010100'. " G/L account populate_ftpost 'P' 1 'BSEG-SGTXT' 'Clearing vendor invoice'. populate_ftpost 'P' 1 'BSEG-WRBTR' '1700'. " amount CALL FUNCTION 'POSTING_INTERFACE_START' EXPORTING i_client = sy-mandt i_function = 'C' i_mode = 'N' i_keep = 'X' i_update = 'S' i_user = sy-uname. IF sy-subrc <> 0. MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4. ENDIF. CALL FUNCTION 'POSTING_INTERFACE_CLEARING' EXPORTING i_auglv = 'AUSGZAHL' i_tcode = 'FB05' i_sgfunct = 'C' IMPORTING e_msgid = sy-msgid e_msgno = sy-msgno e_msgty = sy-msgty e_msgv1 = sy-msgv1 e_msgv2 = sy-msgv2 e_msgv3 = sy-msgv3 e_msgv4 = sy-msgv4 TABLES t_blntab = lt_blntab t_ftclear = lt_ftclear t_ftpost = lt_ftpost t_fttax = lt_fttax EXCEPTIONS clearing_procedure_invalid = 1 clearing_procedure_missing = 2 table_t041a_empty = 3 transaction_code_invalid = 4 amount_format_error = 5 too_many_line_items = 6 company_code_invalid = 7 screen_not_found = 8 no_authorization = 9 OTHERS = 10. IF sy-subrc <> 0. MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4. ENDIF. " keep track of document number READ TABLE lt_blntab INDEX 1. CALL FUNCTION 'POSTING_INTERFACE_END' EXCEPTIONS session_not_processable = 1 OTHERS = 2. IF sy-subrc <> 0. MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4. ENDIF. WRITE: lt_blntab-bukrs, lt_blntab-belnr, lt_blntab-gjahr, ' was posted successfully'.ENDFORM. POSTING_INTERFACE_START 函数 CALL FUNCTION 'POSTING_INTERFACE_START'EXPORTING i_client = sy-mandt i_function = 'C' i_mode = 'N' i_keep = 'X' i_update = 'S' i_user = sy-uname.
这个函数主要给出 client, user id 以及后续 BDC 的一些参数。注意参数中 i_mode 参数，这个参数的含义与 BDC 模式的含义相同：
N 后台处理，没有界面和错误
E 提示错误，建议程在发布之前通过 E 模式调试错误，运行的时候可以跳转到前台调试，方便看出错误的原因
A 显示前台每一步操作，也可用于调试 POSTING_INTERFACE_CLEARING 函数
这个函数式程序处理的主体，调用代码如下：
CALL FUNCTION 'POSTING_INTERFACE_CLEARING' EXPORTING i_auglv = 'AUSGZAHL' i_tcode = 'FB05' i_sgfunct = 'C' TABLES t_blntab = lt_blntab t_ftclear = lt_ftclear t_ftpost = lt_ftpost t_fttax = lt_fttax . auglv 参数
auglv 参数表示清账过程，数据来自 T041A 表，比如上面的 AUSGZAHL 表示付款。
FTCLEAR 表参数
FTCLEAR 表参数是要要被清账的数据。对于本篇的会计凭证来说，我们要对应付账款（供应商）进行清账，所以需要填写 FTCLEAR 表参数如下：
" ftclear 是清账的数据的表参数 DATA: lt_ftclear TYPE STANDARD TABLE OF ftclear, ls_ftclear LIKE LINE OF lt_ftclear. " populate ftclear table parameter CLEAR ls_ftclear. ls_ftclear-agkoa = 'K'. " k for vendor ls_ftclear-agbuk = 'Z900'. ls_ftclear-selfd = 'BELNR'. ls_ftclear-xnops = 'X'. " No Special G/L items ls_ftclear-selvon = '1900000001'. APPEND ls_ftclear TO lt_ftclear.
可以看到，清账以会计凭证号码 1900000001 为基础，这是清账的一种方法而已。
FTPOST 表参数
FTPOST 表参数表示要过账的数据，包括 document header 和 line items。对于本次的过账凭证来说，最后生成的会计凭证为：
DR: 应付账款 1700CR: 现金 （10010100）1700
贷方现金这一行就是过账数据，我们需要将 document header 和现金这一行填写到 PTPOST 参数中，为减少代码量，先定义一个宏。
DEFINE populate_ftpost. clear ls_ftpost. ls_ftpost-stype = &1. ls_ftpost-count = &2. ls_ftpost-fnam = &3. ls_ftpost-fval = &4. append ls_ftpost to lt_ftpost.END-OF-DEFINITION. " ftpost 是过账的抬头和行项目的表参数 DATA: lt_ftpost TYPE STANDARD TABLE OF ftpost, ls_ftpost LIKE LINE OF lt_ftpost. " populate ftpost table paramter " 分为header和line item，line item按行填充 " 首先填写header (K) populate_ftpost 'K' 1 'BKPF-BUKRS' 'Z900'. " company code populate_ftpost 'K' 1 'BKPF-BLART' 'KA'. " document type populate_ftpost 'K' 1 'BKPF-BLDAT' sy-datum. " posting date populate_ftpost 'K' 1 'BKPF-BUDAT' sy-datum. populate_ftpost 'K' 1 'BKPF-WAERS' 'CNY'. " currency populate_ftpost 'K' 1 'BKPF-BKTXT' 'Clearing 1900000001'. " header text " 按行填写行项目的字段 (P) populate_ftpost 'P' 1 'RF05A-NEWBS' '50'. " posting key populate_ftpost 'P' 1 'BSEG-HKONT' '10010100'. " G/L account populate_ftpost 'P' 1 'BSEG-SGTXT' 'Clearing vendor invoice'. populate_ftpost 'P' 1 'BSEG-WRBTR' '1700'. " amount
在填充参数的时候，ftpost-stype 为 K 表示 document header, P 表示 行项目。另外，我们可以看到，在一张凭证中 ftpost-count 用于关联 document header 和 line item。
blntab 表参数
blntab 表参数用于记录生成的会计凭证号码信息：
DATA: lt_blntab LIKE TABLE OF blntab WITH HEADER LINE." keep track of document numberREAD TABLE lt_blntab INDEX 1.WRITE: lt_blntab-bukrs, lt_blntab-belnr, lt_blntab-gjahr, ' was posted successfully'. POSTING_INTERFACE_END
如果 clearing 函数成功，调用函数 POSTING_INTERFACE_END
call function 'POSTING_INTERFACE_END' exporting i_bdcimmed = 'X' exceptions session_not_processable = 1 others = 2.