java使用poi生成excel的步骤

使用poi生成excel通常包含一下几个步骤

• 创建一个工作簿
• 创建一个sheet
• 创建一个Row对象
• 创建一个cell对象(1个row+1个cell构成一个单元格)
• 设置单元格内容
• 设置单元格样式. 字体 字体大小 是否加粗
• 保存
• 关闭流对象

生成一个工作簿

2010以上格式使用XSSFWorkBook对象, 2003格式使用HSSFWorkBook对象, 其他对象操作基本一样.

生成2003格式

public void test1() {
    HSSFWorkbook workbook = new HSSFWorkbook();
    
    CellStyle cellStyle = workbook.createCellStyle();
    cellStyle.setBorderBottom(BorderStyle.THIN);
    cellStyle.setBorderLeft(BorderStyle.THIN);
    cellStyle.setBorderRight(BorderStyle.THIN);
    cellStyle.setBorderTop(BorderStyle.THIN);
    
    Font font = workbook.createFont();
    font.setFontName(\"宋体\"); 
    font.setFontHeightInPoints((short) 12);
    cellStyle.setFont(font);
   
    HSSFSheet sheet = workbook.createSheet(\"Sheet1\");
    //设置单元格宽度
    sheet.setColumnWidth(0, 30 * 256);
    sheet.setColumnWidth(1, 30 * 256);
    sheet.setColumnWidth(2, 30 * 256);
    
    Row row0 = sheet.createRow(0);
    Cell cell0 = row0.createCell(0);
    cell0.setCellValue(\"序号\");
    cell0.setCellStyle(cellStyle);
    
    Cell cell1 = row0.createCell(1);
    cell1.setCellValue(\"姓名\");
    
    Cell cell2 = row0.createCell(2);
    cell2.setCellValue(\"成绩\");
    
    OutputStream os = null;
    try {
        os = new FileOutputStream(\"d:\\\\测试生成2003.xls\");
        workbook.write(os);
        os.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

生成2010以上格式

@Test
public void test2() {
    XSSFWorkbook workbook = new XSSFWorkbook();
    
    CellStyle cellStyle = workbook.createCellStyle();
    cellStyle.setBorderBottom(BorderStyle.THIN);
    cellStyle.setBorderLeft(BorderStyle.THIN);
    cellStyle.setBorderRight(BorderStyle.THIN);
    cellStyle.setBorderTop(BorderStyle.THIN);
    
    Font font = workbook.createFont();
    font.setFontName(\"宋体\");
    font.setFontHeightInPoints((short) 12);
    cellStyle.setFont(font);
    
    
    XSSFSheet sheet = workbook.createSheet(\"Sheet1\");
    Row row0 = sheet.createRow(0);
    Cell cell0 = row0.createCell(0);
    cell0.setCellValue(\"序号\");
    cell0.setCellStyle(cellStyle);
    
    Cell cell1 = row0.createCell(1);
    cell1.setCellValue(\"姓名\");
    
    Cell cell2 = row0.createCell(2);
    cell2.setCellValue(\"成绩\");
    
    OutputStream os = null;
    try {
        os = new FileOutputStream(\"d:\\\\测试生成2010.xlsx\");
        workbook.write(os);
        os.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

合并单元格

合并单元格在生成excel中算常见的一个场景, 通常先合并单元, 单元格内容居中,并设置单元格边框.
poi合并单元格使用CellRangeAddress类, 构造函数包括4个参数firstRow, lastRow, firstCol, lastCol根据自己需要传入行和列.

public CellRangeAddress(int firstRow, int lastRow, int firstCol, int lastCol) {
}

合并单元格后设置边框poi已提供了RegionUtil静态类, 可直接使用.

CellRangeAddress region = new CellRangeAddress(0, 0, 0, 2);
sheet.addMergedRegion(region);

RegionUtil.setBorderBottom(BorderStyle.THIN, region, sheet);
RegionUtil.setBorderLeft(BorderStyle.THIN, region, sheet);
RegionUtil.setBorderTop(BorderStyle.THIN, region, sheet);
RegionUtil.setBorderRight(BorderStyle.THIN, region, sheet);

设置单元格样式

左右居中 上下居中 自动换行

cellStyle.setAlignment(HorizontalAlignment.CENTER);
cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
cellStyle.setWrapText(true);

使用SpringMVC/SpringBoot导出excel

@Controller
@GetMapping(\"/excel2003\")
public void excel2003(HttpServletResponse httpServletResponse){
    try {
        //2010格式设置
        //response.setContentType(\"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet\");
        //2003格式设置
        response.setContentType(\"application/vnd.ms-excel\");
        httpServletResponse.addHeader(\"Content-Disposition\", \"attachment;fileName=\" + URLEncoder.encode(\"学生成绩单.xls\", \"utf-8\"));

        ServletOutputStream outputStream = httpServletResponse.getOutputStream();

        HSSFWorkbook workbook = new HSSFWorkbook();

        CellStyle cellStyle = workbook.createCellStyle();
        cellStyle.setBorderBottom(BorderStyle.THIN);
        cellStyle.setBorderLeft(BorderStyle.THIN);
        cellStyle.setBorderRight(BorderStyle.THIN);
        cellStyle.setBorderTop(BorderStyle.THIN);

        Font font = workbook.createFont();
        font.setFontName(\"宋体\");
        font.setFontHeightInPoints((short) 12);
        cellStyle.setFont(font);

        HSSFSheet sheet = workbook.createSheet(\"Sheet1\");
        Row row0 = sheet.createRow(0);
        Cell cell0 = row0.createCell(0);
        cell0.setCellValue(\"序号\");
        cell0.setCellStyle(cellStyle);

        Cell cell1 = row0.createCell(1);
        cell1.setCellValue(\"姓名\");

        Cell cell2 = row0.createCell(2);
        cell2.setCellValue(\"成绩\");

        workbook.write(outputStream);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

总结

如果你在web项目中导出excel后,打开excel文件时提示文件已损坏,但是文件还可以打开, 则需要在HttpServletResponse上设置响应头, 2003和2010设置方式不同
2003
response.setContentType("application/vnd.ms-excel");
2010
response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");

下载文件名如果包含中文的话需要编码
httpServletResponse.addHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode("学生成绩单.xls", "utf-8"));
这种设置在浏览器里下载文件中文是没问题的, 只是如果你使用Swagger或者Postman测试的话,文件名还是经过编码的, 这个没问题说明文件下载已经没问题.