如何使用[Apache POI]创建从属下拉列表 [英] How to create a dependent drop down list using [Apache POI]

问题描述

在这里，我正在使用[Apache POI]创建一个excel模板，因为该用户可以填充数据.在那两个下拉列表中.想要创建一个依赖于上一个单元格的下拉列表的下拉列表. 例如::如果我在单元格3中选择蔬菜类别，并且大米，凝乳，牛奶"项目将出现在单元格4的从属下拉列表中.代码如下.

Here I am creating one excel template using [Apache POI] in that user can fill data. In that two drop down list are there. Want to create a drop down list that depends on previous cell's drop down. For example: If I select veg category in cell 3, and "rice, curd, milk" items will appear in the dependent drop down list in cell 4. Codes are below.

此处正在收集数据

   List<InternetItemResponse> internetItems = internetItemService.getAllByHotelId(hotelId);
    if (CollectionUtils.isNotEmpty(internetItems)) {
    String[] itemsName = new String[internetItems.size()];
    String[] itemsCategory = new String[internetItems.size()];
    String itemName;
    String itemCategory;
    Map<String, Set<String>> categoryVsItemName = new HashMap<>();
    Set<String> itemList;
    for (int i = 0; i < internetItems.size(); i++) {
        InternetItemResponse itemResponse = internetItems.get(i);
        if (itemResponse != null) {
            itemCategory = itemResponse.getCategory();
            if (!StringUtils.isEmpty(itemCategory)) {
                itemsCategory[i] = itemCategory;
                itemName = itemResponse.getTitle();
                itemsName[i] = itemName;
                if (CollectionUtils.isEmpty(categoryVsItemName.get(itemCategory))) {
                    itemList = new HashSet<>();
                    itemList.add(itemName);
                    categoryVsItemName.put(itemCategory, itemList);
                } else {
                    categoryVsItemName.get(itemCategory).add(itemName);
                }
            }
        }
    }
}

在下拉菜单中分配数据

// Setting drop down values
    for (int i = 0; i < headerColumns.length; i++) {
        if (i == 3) {
            XSSFDataValidationHelper mealdvHelper = new XSSFDataValidationHelper((XSSFSheet) sheet);
            XSSFDataValidationConstraint mealdvConstraint = (XSSFDataValidationConstraint) mealdvHelper
                    .createExplicitListConstraint(itemsCategory);
            // CellRangeAddressList(int firstRow, int lastRow, int firstCol, int lastCol)
            CellRangeAddressList addressListmeal = new CellRangeAddressList(1, 99, i, i);
            XSSFDataValidation categoryDataValidation = (XSSFDataValidation) mealdvHelper
                    .createValidation(mealdvConstraint, addressListmeal);
            categoryDataValidation.setShowErrorBox(true);
            categoryDataValidation.setSuppressDropDownArrow(true);
            categoryDataValidation.setShowPromptBox(true);
            sheet.addValidationData(categoryDataValidation);
        } else if (i == 4) {
            XSSFDataValidationHelper rmCategorydvHelper = new XSSFDataValidationHelper((XSSFSheet) sheet);
            XSSFDataValidationConstraint rmCategorydvConstraint = (XSSFDataValidationConstraint) rmCategorydvHelper
                    .createExplicitListConstraint(itemsName);
            CellRangeAddressList addressListrmCategory = new CellRangeAddressList(1, 99, i, i);
            XSSFDataValidation itemNameValidation = (XSSFDataValidation) rmCategorydvHelper
                    .createValidation(rmCategorydvConstraint, addressListrmCategory);
            itemNameValidation.setShowErrorBox(true);
            itemNameValidation.setSuppressDropDownArrow(true);
            itemNameValidation.setShowPromptBox(true);
            sheet.addValidationData(itemNameValidation);
        }
    }

推荐答案

创建从属下拉列表不是apache poi所能做的. apache poi库用于创建Excel文件.下拉列表的依赖性必须在运行生成文件的Excel s GUI中进行管理.Apache poi仅可以创建Excel文件，这样才可以.

Creating dependent dropdown lists is nothing what apache poi could do. The apache poi library is made for creating Excel files. The dependency of dropdown lists must be managed in Excels GUI where the generated file is running in. Apache poi only can create the Excel file so that this is possible then.

一种方法是将命名范围用于数据验证列表，然后使用INDIRECT获取其名称.因此，主列表包含从属列表的命名范围的名称.然后从属列表使用=INDIRECT([cell of main list])来获取从主列表中选择姓名的从属列表.

One approach is using named ranges for the data validation lists who's names are then got using INDIRECT. So the main list contains the names of the named ranges of the dependent lists. And the dependent list uses =INDIRECT([cell of main list]) then to get the dependent list who's name is selected from main list.

如何使用apache poi创建此示例:

import java.io.FileOutputStream;

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import org.apache.poi.ss.util.*;

import java.util.Map;
import java.util.HashMap;

class CreateExcelDependentDataValidationListsUsingNamedRanges {

 public static void main(String[] args) throws Exception {

   //some data
   Map<String, String[]> categoryItems = new HashMap<String, String[]>();
   categoryItems.put("Countries", new String[]{"France", "Germany", "Italy"});
   categoryItems.put("Capitals", new String[]{"Paris", "Berlin", "Rome"});
   categoryItems.put("Fruits", new String[]{"Apple", "Peach", "Banana", "Orange"});

   Workbook workbook = new XSSFWorkbook();

   //hidden sheet for list values
   Sheet sheet = workbook.createSheet("ListSheet");

   Row row;  
   Name namedRange;
   String colLetter;
   String reference;

   int c = 0;
   //put the data in
   for (String key : categoryItems.keySet()) {
    int r = 0;
    row = sheet.getRow(r); if (row == null) row = sheet.createRow(r); r++;
    row.createCell(c).setCellValue(key);
    String[] items = categoryItems.get(key);
    for (String item : items) {
     row = sheet.getRow(r); if (row == null) row = sheet.createRow(r); r++;
     row.createCell(c).setCellValue(item);
    }
    //create names for the item list constraints, each named from the current key
    colLetter = CellReference.convertNumToColString(c);
    namedRange = workbook.createName();
    namedRange.setNameName(key);
    reference = "ListSheet!$" + colLetter + "$2:$" + colLetter + "$" + r;
    namedRange.setRefersToFormula(reference);
    c++;
   }

   //create name for Categories list constraint
   colLetter = CellReference.convertNumToColString((c-1));
   namedRange = workbook.createName();
   namedRange.setNameName("Categories");
   reference = "ListSheet!$A$1:$" + colLetter + "$1";
   namedRange.setRefersToFormula(reference);

   //unselect that sheet because we will hide it later
   sheet.setSelected(false);


   //visible data sheet
   sheet = workbook.createSheet("Sheet1");

   sheet.createRow(0).createCell(0).setCellValue("Select Category");
   sheet.getRow(0).createCell(1).setCellValue("Select item from that category");

   sheet.setActiveCell(new CellAddress("A2"));

   sheet.autoSizeColumn(0);
   sheet.autoSizeColumn(1);

   //data validations
   DataValidationHelper dvHelper = sheet.getDataValidationHelper();
   //data validation for categories in A2:
   DataValidationConstraint dvConstraint = dvHelper.createFormulaListConstraint("Categories");
   CellRangeAddressList addressList = new CellRangeAddressList(1, 1, 0, 0);            
   DataValidation validation = dvHelper.createValidation(dvConstraint, addressList);
   sheet.addValidationData(validation);

   //data validation for items of the selected category in B2:
   dvConstraint = dvHelper.createFormulaListConstraint("INDIRECT($A$2)");
   addressList = new CellRangeAddressList(1, 1, 1, 1);            
   validation = dvHelper.createValidation(dvConstraint, addressList);
   sheet.addValidationData(validation);

   //hide the ListSheet
   workbook.setSheetHidden(0, true);
   //set Sheet1 active
   workbook.setActiveSheet(1);

   FileOutputStream out = new FileOutputStream("CreateExcelDependentDataValidationListsUsingNamedRanges.xlsx");
   workbook.write(out);
   workbook.close();
   out.close();

 }
}

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