ABAP 实现将上传文件转换为xstring，再将xstring转化为文件并打开，且解决乱码问题

在ABAP中，将上传文件转换为xstring，再将xstring转化为文件并打开可以通过以下步骤实现：

1. 将上传文件转换为xstring。

DATA: lv_xstring TYPE xstring.

CALL FUNCTION 'SCMS_BINARY_TO_XSTRING'
  EXPORTING
    input_length       = cl_gui_frontend_services=>file_size( p_file )
  IMPORTING
    buffer             = lv_xstring
  TABLES
    binary_tab         = lt_binary.

2. 将xstring转换为文件并保存。

DATA: lv_file TYPE string.

CALL METHOD cl_gui_frontend_services=>gui_download
  EXPORTING
    bin_filesize        = cl_gui_frontend_services=>file_size( lv_xstring )
    filename            = lv_file
    filetype            = 'BIN'
  IMPORTING
    filelength          = lv_filesize
  CHANGING
    data_tab            = lt_binary
  EXCEPTIONS
    file_write_error    = 1
    no_batch            = 2
    gui_refuse_filetransfer = 3
    invalid_type        = 4
    no_authority        = 5
    unknown_error       = 6
    header_not_allowed  = 7
    separator_not_allowed = 8
    filesize_not_allowed = 9
    header_too_long     = 10
    dp_error_create     = 11
    dp_error_send       = 12
    dp_error_write      = 13
    unknown_dp_error    = 14
    access_denied       = 15
    dp_out_of_memory    = 16
    disk_full           = 17
    dp_timeout          = 18
    file_not_found      = 19
    dataprovider_exception = 20
    control_flush_error = 21
    OTHERS              = 22.

3. 打开文件。

CALL FUNCTION 'WS_EXECUTE'
  EXPORTING
    program = lv_file.

为了解决乱码问题，可以在打开文件前将xstring进行转换。例如：

DATA: lv_file TYPE string.

CALL FUNCTION 'SCMS_XSTRING_TO_BINARY'
  EXPORTING
    buffer              = lv_xstring
  IMPORTING
    output_length       = lv_filesize
  TABLES
    binary_tab          = lt_binary.

CALL METHOD cl_gui_frontend_services=>gui_download
  EXPORTING
    bin_filesize        = lv_filesize
    filename            = lv_file
    filetype            = 'BIN'
  IMPORTING
    filelength          = lv_filesize
  CHANGING
    data_tab            = lt_binary
  EXCEPTIONS
    ...

这样就可以避免文件内容乱码的问题了。