File Handling in ABAP

 

File :-

• File is a place where data is stored. File handling means the various operations like Opening the File, Closing the file, deleting the file, Reading the file, Writing the file.

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File Handling on Presentation Server :-

• To work with files on Presentation Server, SAP provided the various Function Modules.
  1. GUI_UPLOAD :- Reading data from a file on Presentation server.
  2. GUI_DOWNLOAD :- Writing data to a file on Presentation server.

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let’s take a requirement to understand it more clearly

Requirement :-

• We have a employee record in a notepad and we have to read the data from the notepad.

  
  
  

  
  

• We will read this data and display inform of ALV.

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Solution :-

• Step 1 :- Create a executable program in ABAP Editor.

  
  
  

  
  

• Step 2 :- Create a parameter of type LOCALFILE.

  
  
  

  
  

• Step 3 :- Now we need to give a F4 help for our local file.

  • To achieve this purpose, we will use AT SELECTION-SCREEN on value request event.

    
    
    

    
    

• Step 4 :- Now, when user will click F4 on selection screen, I want to show the presentation server of my local system.

  • So, for that purpose, I will use F4_FILENAME function module.
  
  
  

  
  

• Step 5 :- We will create a type structure and a internal table for that, so that we can use it to store our data.

  
  
  

  
  

• Step 6 :- We will use GUI Upload function module to upload data into the internal table.

  
  
  

  
  

• Step 7 :- Now, I will use factory method of CL_SALV_TABLE class to display in form of ALV.

  
  
  

  
  

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Code :-

*&---------------------------------------------------------------------*
*& Report ZAR_READ_FILE
*&---------------------------------------------------------------------*
*&
*&---------------------------------------------------------------------*
REPORT ZAR_READ_FILE.

TYPES : begin of ty_employee,
    EMP_ID(10) type N,
    EMP_NAME(40) type c,
  end of ty_employee.

DATA : lt_file type table of ty_employee.
DATA : file type string.

PARAMETERS : p_file type localfile.

AT SELECTION-SCREEN ON VALUE-REQUEST FOR p_file.

  CALL FUNCTION 'F4_FILENAME'
   EXPORTING
     PROGRAM_NAME        = SYST-CPROG
     DYNPRO_NUMBER       = SYST-DYNNR
     FIELD_NAME          = ' '
   IMPORTING
     FILE_NAME           = p_file
            .

START-OF-SELECTION.

  file = p_file.
  CALL FUNCTION 'GUI_UPLOAD'
    EXPORTING
      filename                      = file
*     FILETYPE                      = 'ASC'
     HAS_FIELD_SEPARATOR           = 'X'
    tables
      data_tab                      = lt_file
   EXCEPTIONS
     FILE_OPEN_ERROR               = 1
     FILE_READ_ERROR               = 2
     NO_BATCH                      = 3
     GUI_REFUSE_FILETRANSFER       = 4
     INVALID_TYPE                  = 5
     NO_AUTHORITY                  = 6
     UNKNOWN_ERROR                 = 7
     BAD_DATA_FORMAT               = 8
     HEADER_NOT_ALLOWED            = 9
     SEPARATOR_NOT_ALLOWED         = 10
     HEADER_TOO_LONG               = 11
     UNKNOWN_DP_ERROR              = 12
     ACCESS_DENIED                 = 13
     DP_OUT_OF_MEMORY              = 14
     DISK_FULL                     = 15
     DP_TIMEOUT                    = 16
     OTHERS                        = 17
            .

  TRY.
  CALL METHOD cl_salv_table=>factory
    EXPORTING
      list_display   = IF_SALV_C_BOOL_SAP=>FALSE
    IMPORTING
      r_salv_table   = data(lo_alv)
    CHANGING
      t_table        = lt_file
      .
    CATCH cx_salv_msg.
  ENDTRY.
  lo_alv->display( ).

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Execute the Program :-

• Press F4 and select the file from your local system.

• Press F8.
• Click on allow.