spring boot 創建excel並以流的方式返回前端

• 1.導入pom依賴

<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.1-final</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.5-final</version>
</dependency>

• 2 controller測試

@GetMapping("/excel")
    public ResponseEntity<byte[]> excel() throws IOException {
        HSSFWorkbook wb = new HSSFWorkbook();
        HSSFSheet sheet = wb.createSheet();
        HSSFCellStyle style = wb.createCellStyle();
        style.setFillForegroundColor((short) 13);
        //設置單元格前景色
        style.setFillForegroundColor((short) 13);
        //設置圖案樣式
        style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
        style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
        style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
        HSSFFont font = wb.createFont();
        font.setFontName("黑體");
        font.setFontHeightInPoints((short) 16);
        font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
        style.setFont(font);
        //設置單元格合併
        //Region region = new Region(0,(short) 0,0,(short) 6);
        //sheet.addMergedRegion(region);
        for (int rownum = 0; rownum < 50; rownum++) {
            HSSFRow hssfRow = sheet.createRow(rownum);
            for (int cellnum = 0; cellnum < 30; cellnum++) {
                HSSFCell cell = hssfRow.createCell((short) cellnum);
                cell.setCellValue(rownum + "" + cellnum);
            }
        }
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        try {
            wb.write(outputStream);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            outputStream.close();
        }
        HttpHeaders httpHeaders = new HttpHeaders();
        String fileName = new String("測試.xls".getBytes("UTF-8"), "iso-8859-1");
        httpHeaders.setContentDispositionFormData("attachment", fileName);
        httpHeaders.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        ResponseEntity<byte[]> filebyte = new ResponseEntity<byte[]>(outputStream.toByteArray(), httpHeaders, HttpStatus.CREATED);
        try {
            outputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            outputStream.close();
        }
        return filebyte;
    }