如何在Spring Boot中創建Apache POI Excel視圖配置

Question

當我想使用spring boot web將數據導出到excel時，我遇到了問題。

我使用Thymeleaf作為模板引擎（由spring boot自動配置）。 但是當我在我的附加配置中添加XmlViewResolver時，我的百萬美元視圖由XmlViewResolver解決，這絕對無法解決。 我嘗試通過創建新類解決該問題，擴展WebMvcConfigurerAdapter並在那里重新配置thymeleaf模板解析器。 但是我的模板無法解決，因為找不到我的模板位置。 我把它放進去：

 /resources/template/ 

請幫我。

Answer 1

使用Spring Boot，您無需任何額外配置即可生成Excel文件。

使用AbstractExcelView創建一個返回ModelAndView的控制器：

@Controller
public class MyController {

    @RequestMapping(value="/myexcel", method=RequestMethod.GET)
    public ModelAndView getMyData(HttpServletRequest request, HttpServletResponse response) throws SQLException{
        Map<String, Object> model = new HashMap<String, Object>();
        //Sheet Name
        model.put("sheetname", "TestSheetName");
        //Headers List
        List<String> headers = new ArrayList<String>();
        headers.add("Column1");
        headers.add("Column2");
        headers.add("Column3");
        model.put("headers", headers);
        //Results Table (List<Object[]>)
        List<List<String>> results = new ArrayList<List<String>>();
        List<String> l1 = new ArrayList<String>();
        l1.add("A1");
        l1.add("B1");
        l1.add("C1");
        results.add(l1);
        List<String> l2 = new ArrayList<String>();
        l2.add("A2");
        l2.add("B2");
        l2.add("C2");
        results.add(l2);
        model.put("results",results);
        response.setContentType( "application/ms-excel" );
        response.setHeader( "Content-disposition", "attachment; filename=myfile.xls" );         
        return new ModelAndView(new MyExcelView(), model);
    }

然后構建您的AbstractExcelView，如：

public class MyExcelView extends AbstractExcelView
{
    @SuppressWarnings("unchecked")
    protected void buildExcelDocument(Map<String, Object> model,
            HSSFWorkbook workbook,
            HttpServletRequest request,
            HttpServletResponse response)
    {
        //VARIABLES REQUIRED IN MODEL
        String sheetName = (String)model.get("sheetname");
        List<String> headers = (List<String>)model.get("headers");
        List<List<String>> results = (List<List<String>>)model.get("results");
        List<String> numericColumns = new ArrayList<String>();
        if (model.containsKey("numericcolumns"))
            numericColumns = (List<String>)model.get("numericcolumns");
        //BUILD DOC
        HSSFSheet sheet = workbook.createSheet(sheetName);
        sheet.setDefaultColumnWidth((short) 12);
        int currentRow = 0;
        short currentColumn = 0;
        //CREATE STYLE FOR HEADER
        HSSFCellStyle headerStyle = workbook.createCellStyle();
        HSSFFont headerFont = workbook.createFont();
        headerFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
        headerStyle.setFont(headerFont); 
        //POPULATE HEADER COLUMNS
        HSSFRow headerRow = sheet.createRow(currentRow);
        for(String header:headers){
            HSSFRichTextString text = new HSSFRichTextString(header);
            HSSFCell cell = headerRow.createCell(currentColumn); 
            cell.setCellStyle(headerStyle);
            cell.setCellValue(text);            
            currentColumn++;
        }
        //POPULATE VALUE ROWS/COLUMNS
        currentRow++;//exclude header
        for(List<String> result: results){
            currentColumn = 0;
            HSSFRow row = sheet.createRow(currentRow);
            for(String value : result){//used to count number of columns
                HSSFCell cell = row.createCell(currentColumn);
                if (numericColumns.contains(headers.get(currentColumn))){
                    cell.setCellType(HSSFCell.CELL_TYPE_NUMERIC);
                    cell.setCellValue(NumUtils.extractDoubleOrZero(value));
                } else {
                    HSSFRichTextString text = new HSSFRichTextString(value);                
                    cell.setCellValue(text);                    
                }
                currentColumn++;
            }
            currentRow++;
        }
    }
}