UI5与后端的文件交互（二）

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前言

这系列文章详细记录在Fiori应用中如何在前端和后端之间使用文件进行交互。
这篇的主要内容有：

1.后端RAP的开发（S4HANA On-Premise）
- 开发Action
2.前端（UI5）读取Excel文件并保存到后端
- 传输文件流，并在ABAP中解析数据

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一、开发Action

1. 创建Structure

• 用于在UI5中把文件流传输到后端

@EndUserText.label : 'File'
@AbapCatalog.enhancement.category : #NOT_EXTENSIBLE
define structure ymoon_s010 {
  content : abap.string(0);
}

2. BEDF添加Action

managed implementation in class zbp_moon_i_010 unique;
strict ( 2 );

define behavior for ymoon_i_010 alias Student
persistent table YMOON_T010
early numbering
lock master
authorization master ( instance )
//etag master <field_name>
{
  create;
  update;
  delete;

  //Add Action
  static action upload_file parameter ymoon_s010;

}

3. class中实现Action

这里使用abap2xlsx解析excel文件

  method upload_file.

    types:begin of upload_type,
            name   type ymoon_t010-name,
            age    type ymoon_t010-age,
            gender type ymoon_t010-gender,
            city   type ymoon_t010-city,
          end of upload_type.
    data:ls_upload type upload_type.
    data:lt_ymoon_t010 type table of ymoon_t010,
         ls_ymoon_t010 type  ymoon_t010.

    "获取UI5传送的parameter
    data(content) = keys[ 1 ]-%param-content.

    "拆分数据，只保留excel内容 - lv_data
    split content at `;` into data(lv_dummy) data(lv_data).
    split lv_data at `,` into data(lv_format) lv_data.

    data:lv_excel_data type xstring.
    "将base64的String转换为xstring
    call function 'SCMS_BASE64_DECODE_STR'
      exporting
        input  = lv_data
      importing
        output = lv_excel_data
      exceptions
        failed = 1
        others = 2.

    "ABAP2XLSX生命
    data: lo_excel  type ref to zcl_excel, "??
          lo_reader type ref to zif_excel_reader,
          lo_root   type ref to cx_root. "异常类
    data: lo_worksheet   type ref to zcl_excel_worksheet,
          highest_column type zexcel_cell_column,
          highest_row    type int4,
          column         type zexcel_cell_column value 1,
          col_str        type zexcel_cell_column_alpha,
          row            type int4               value 1,
          value          type zexcel_cell_value,
          converted_date type d.

    "创建reader
    create object lo_reader type zcl_excel_reader_2007.

    lo_excel = lo_reader->load( i_excel2007 = lv_excel_data ).
    lo_worksheet = lo_excel->get_active_worksheet( ).

    "计算行列最大值
    highest_column = lo_worksheet->get_highest_column( ).
    highest_row    = lo_worksheet->get_highest_row( ).

    row += 1.

    while row <= highest_row.
      while column <= highest_column.
        col_str = zcl_excel_common=>convert_column2alpha( column ).
        "读取cell数据
        lo_worksheet->get_cell(
          exporting
            ip_column = col_str
            ip_row    = row
          importing
            ep_value = value
        ).


        assign component column of structure ls_upload to field-symbol(<fs>).
        <fs> = value.
        column = column + 1.
      endwhile.

      column = 1.

      clear ls_ymoon_t010.
      move-corresponding ls_upload to ls_ymoon_t010.
      ls_ymoon_t010-uuid = cl_system_uuid=>create_uuid_x16_static( ).
      append ls_ymoon_t010 to lt_ymoon_t010.
      row = row + 1.
    endwhile.

    modify ymoon_t010 from table lt_ymoon_t010.


  endmethod.

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二、修改UI5 项目

1. 添加一个按钮

• 点击时将触发onUploadStream事件

<Button
    id="_IDGenButton4"
    press="onUploadStream"
    icon="sap-icon://upload"
    text="Upload Stream"
    type="Success"
    class="sapUiSmallMarginBegin"
/>

2. 定义事件函数

• 这里不解析excel里的数据，只把文件流推给后端

onUploadStream:function(){
                var that = this
                var oModel = this.getView().getModel();
                
                var oFileUploader = this.byId("fileUploader");
                var filename = oFileUploader.getProperty('value')
                var file = oFileUploader.oFileUpload.files[0];


                var reader = new FileReader();
                reader.onload = function (evt) {
                    // 获取base64值
                    var vContent = evt.currentTarget.result;

                    oModel.callFunction("/upload_file",   //BDEF中定义的action名 
                        {
                            method: "POST", // 使用POST 
                            urlParameters: {   //定义的参数，首字母必须要大写 
                                "Content": vContent
                            },
                            success: function (odata, response) {
                                //Model Refresh
                                oModel.refresh(true);
                            },
                            error: function (res) {
                                console.log(res)
                            }
                        })


                }
                //读取文件
                reader.readAsDataURL(file);
            }

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三、测试及解析

1. 测试

2. js中提取到的excel流数据

• 蓝色框里的是我们需要的Excel数据，需要在后端解析
  

3. 后端解析

• 使用SCMS_BASE64_DECODE_STR函数，把base64转为xstring
  

• 再通过zcl_excel_reader_2007对象传入xstring值创建一个zcl_excel对象。 然后使用zcl_excel_worksheet中的get_cell方法提取数据
  

• 数据库
  

接下来的文章制作一个任意文件的上传和下载