spring boot:使用poi導出excel電子表格文件(spring boot 2.3.1)

一，什么是poi?

1,poi

poi是用來兼容微軟文檔格式的java api，

它是apache的頂級項目之一，

也是我們在生產環境中導出excel時使用最多的庫

 

2,poi官方網站：

http://poi.apache.org/

 

說明：劉宏締的架構森林是一個專注架構的博客，地址：https://www.cnblogs.com/architectforest

         對應的源碼可以訪問這里獲取： https://github.com/liuhongdi/

說明：作者:劉宏締 郵箱: [e-mail]

 

二，演示項目的相關信息

1,項目地址:

https://github.com/liuhongdi/exportexcel

 

2,項目說明：

        讀取數據庫中的商品數據，

        保存成excel表格文件，或下載excel表格文件

 

3，項目結構，如圖:

 

三，配置文件說明：

1,pom.xml

        <!--引入poi begin-->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>4.1.2</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>4.1.2</version>
        </dependency>
        <!--poi   end-->

        <!--mybatis begin-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.3</version>
        </dependency>
        <!--mybatis end-->

        <!--mysql begin-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--mysql end-->

說明：導入poi依賴是用來實現導出excel表格功能

 

2,application.properties

#mysql
spring.datasource.url=jdbc:mysql://localhost:3306/store?characterEncoding=utf8&useSSL=false
spring.datasource.username=root
spring.datasource.password=lhddemo
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

#mybatis
mybatis.mapper-locations=classpath:/mapper/*Mapper.xml
mybatis.type-aliases-package=com.example.demo.mapper
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

 

3,數據表建表sql

CREATE TABLE `goods` (
 `goodsId` int(11) NOT NULL AUTO_INCREMENT COMMENT 'id',
 `goodsName` varchar(500) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT 'name',
 `subject` varchar(200) NOT NULL DEFAULT '' COMMENT '標題',
 `price` decimal(15,2) NOT NULL DEFAULT '0.00' COMMENT '價格',
 `stock` int(11) NOT NULL DEFAULT '0' COMMENT 'stock',
 PRIMARY KEY (`goodsId`)
) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci COMMENT='商品表'

 

四，java代碼說明

1,ExcelUtil.java

public class ExcelUtil {

    //save excel to a file
    public static void  saveExcelFile( HSSFWorkbook wb, String filepath){

        File file = new File(filepath);
        if (file.exists()) {
            file.delete();
        }
        try {
            wb.write(new FileOutputStream(file));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //download a execl file
    public static void downExecelFile(HSSFWorkbook wb,String filename) {
        ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletResponse response = servletRequestAttributes.getResponse();
        try {
        // 輸出Excel文件
        OutputStream output = response.getOutputStream();
        response.reset();
        //設置文件頭
        response.setHeader("Content-Disposition",
                "attchement;filename=" + new String(filename.getBytes("utf-8"),
                        "ISO8859-1"));
        response.setContentType("application/msexcel");
        wb.write(output);
        wb.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

分別實現了把HSSFWorkbook保存成文件和下載兩個功能

 

2,HomeController.java

@RestController
@RequestMapping("/home")
public class HomeController {

    @Resource
    private GoodsMapper goodsMapper;

    @GetMapping("/exportexcel")
    public void exportExcel() {

        HSSFWorkbook wb = new HSSFWorkbook();
        // 根據頁面index 獲取sheet頁
        HSSFSheet sheet = wb.createSheet("商品基本信息");
        createTitle(wb,sheet);

        //設置列寬度
         List<Goods> goodsList = goodsMapper.selectAllGoods();
         //表內容從第二行開始
         int i=1;
         for (Goods goodsOne : goodsList) {
             HSSFRow row = sheet.createRow(i + 1);
             //創建HSSFCell對象 設置單元格的值
             row.createCell(0).setCellValue(goodsOne.getGoodsId());
             row.createCell(1).setCellValue(goodsOne.getGoodsName());
             row.createCell(2).setCellValue(goodsOne.getSubject());
             row.createCell(3).setCellValue(goodsOne.getStock());
             i++;
         }

         //保存成文件
        ExcelUtil.saveExcelFile(wb,"/data/file/html/商品信息.xls");
        //下載文件
        ExcelUtil.downExecelFile(wb,"商品信息.xls");
     }


    //創建標題和表頭
    private void createTitle(HSSFWorkbook workbook,HSSFSheet sheet){
        //用CellRangeAddress合並單元格，在這里作為sheet中的標題
        //參數1：起始行 參數2：終止行 參數3：起始列 參數4：終止列
        CellRangeAddress region1 = new CellRangeAddress(0, 0, 0, 3);
        sheet.addMergedRegion(region1);

        HSSFRow row_title = sheet.createRow(0);
        row_title.setHeightInPoints(26);
        HSSFCell cell_title;
        cell_title = row_title.createCell(0);
        cell_title.setCellValue("商品信息表");

        //設置標題樣式:居中加粗
        HSSFCellStyle style_title = workbook.createCellStyle();
        HSSFFont font_title = workbook.createFont();
        font_title.setBold(true);
        font_title.setFontHeightInPoints((short) 20);
        font_title.setColor(HSSFColor.HSSFColorPredefined.BLUE.getIndex());
        style_title.setFont(font_title);
        style_title.setAlignment(HorizontalAlignment.CENTER);
        style_title.setVerticalAlignment(VerticalAlignment.CENTER);
        cell_title.setCellStyle(style_title);


        //以下為表頭
        HSSFRow row = sheet.createRow(1);
        //設置行高
        row.setHeightInPoints(18);
        //設置列寬度
        sheet.setColumnWidth(0,10*256);
        sheet.setColumnWidth(1,30*256);
        sheet.setColumnWidth(2,30*256);
        sheet.setColumnWidth(3,10*256);
        //設置樣式:居中加粗
        HSSFCellStyle style = workbook.createCellStyle();
        HSSFFont font = workbook.createFont();
        font.setBold(true);
        font.setColor(HSSFColor.HSSFColorPredefined.GREEN.getIndex());
        style.setFont(font);
        style.setAlignment(HorizontalAlignment.CENTER);
        style.setVerticalAlignment(VerticalAlignment.CENTER);
        //添加4個字段
        HSSFCell cell;
        cell = row.createCell(0);
        cell.setCellValue("id");
        cell.setCellStyle(style);

        cell = row.createCell(1);
        cell.setCellValue("商品名稱");
        cell.setCellStyle(style);

        cell = row.createCell(2);
        cell.setCellValue("商品描述");
        cell.setCellStyle(style);

        cell = row.createCell(3);
        cell.setCellValue("庫存數量");
        cell.setCellStyle(style);
    }
}

說明：注意HSSFCellStyle是用來定義表格樣式的類，

我們需要借助它來實現表格中文字的樣式，

包括：HSSFFont:字體樣式，

HorizontalAlignment 水平對齊
VerticalAlignment   垂直對齊

HSSFColor:文字顏色

說明：保存成excel文件和下載excel文件兩功能沒有關聯，

這里只為演示，大家按需求使用

 

3,mybatis用到的mapper類和mapper xml文件，

  商品的對象類: Goods.java

  比較簡單，參見github上的代碼即可，

  不再貼出

 

五，測試效果

1,下載excel

訪問地址:

http://127.0.0.1:8080/home/exportexcel

下載的excel表格內容如圖:

可以看到我們配置的樣式已生效

 

六，查看spring boot的版本

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.3.1.RELEASE)