基于Spring Mvc实现的Excel文件上传下载示例

最近工作遇到一个需求，需要下载excel模板，编辑后上传解析存储到数据库。因此为了更好的理解公司框架，我就自己先用spring mvc实现了一个样例。

基础框架

之前曾经介绍过一个最简单的spring mvc的项目如何搭建，传送门在这里。

这次就基于这个工程，继续实现上传下载的小例子。需要做下面的事情：

1 增加index.html，添加form提交文件

2 引入commons-fileupload、commons-io、jxl等工具包

3 创建upload download接口

4 注入multipartResolver bean

5 在upload中使用HttpServletRequest获取文件流，通过WorkBook进行解析

6 在download中通过HttpServerResponse返回文件流，实现下载

页面

页面很简单，其实就是一个form标签，需要注意的是：

• form中enctype="multipart/form-data"
• action指定访问的url
• input中需要设置name属性，这样后端才能获取到文件对象

<form role="form" action="/upload" method="POST" enctype="multipart/form-data">
  <div class="form-group">
    <label for="file">上传文件</label>
    <input type="file" id="file" name="file">
  </div>
  <button type="submit" class="btn btn-default">提交</button>
</form>

引入commons-fileupload、jxl等工具包

涉及的jar包有：

• commons-fileupload 用于获取上传文件
• jxl 用于解析excel

<!-- springframework begins -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>4.2.4.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>4.2.4.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.0-b01</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
    <dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>2.5</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
    <dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>1.3.2</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/jexcelapi/jxl -->
    <dependency>
      <groupId>jexcelapi</groupId>
      <artifactId>jxl</artifactId>
      <version>2.6</version>
    </dependency>

Xml的配置

在web.xml中需要配置默认的访问页面，因为之前已经设置过拦截的请求是/，因此如果不设置所有的静态页面都会被拦截下来。

<welcome-file-list>
  <welcome-file>index.html</welcome-file>
</welcome-file-list>

在spring的配置文件中，加入CommonsMultipartResolver的bean。

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <!-- set the max upload size100MB -->
    <property name="maxUploadSize">
      <value>104857600</value>
    </property>
    <property name="maxInMemorySize">
      <value>4096</value>
    </property>
  </bean>

上传代码

@RequestMapping("upload")
  public void upload(HttpServletRequest request, HttpServletResponse response) throws IOException, BiffException, WriteException {
    MultipartHttpServletRequest mRequest = (MultipartHttpServletRequest) request;
    MultipartFile file = mRequest.getFile("file");
    Workbook workbook = Workbook.getWorkbook(file.getInputStream());
    //遍历Sheet页
    Arrays.stream(workbook.getSheets())
        .forEach(sheet -> {
          int size = sheet.getRows();
          for(int i=0; i<size; i++){
            //遍历每一行，读取每列信息
            Arrays.stream(sheet.getRow(i)).forEach(cell -> System.out.println(cell.getContents().equals("")?'空':cell.getContents()));
          }
        });

    response.setHeader("Content-Disposition", "attachment; filename=return.xls");
    WritableWorkbook writableWorkbook = ExcelUtils.createTemplate(response.getOutputStream());
    writableWorkbook.write();
    writableWorkbook.close();
  }

下载代码

@RequestMapping("download")
  public void download(HttpServletRequest request, HttpServletResponse response) throws IOException, BiffException, WriteException {
    response.setHeader("Content-Disposition", "attachment; filename=template.xls");
    WritableWorkbook writableWorkbook = ExcelUtils.createTemplate(response.getOutputStream());
    writableWorkbook.write();
    writableWorkbook.close();
  }

模板类

static class ExcelUtils {
    public static WritableWorkbook createTemplate(OutputStream output) throws IOException, WriteException {
      WritableWorkbook writableWorkbook= Workbook.createWorkbook(output);
      WritableSheet wsheet = writableWorkbook.createSheet("测试title", 0);

      CellFormat cf = writableWorkbook.getSheet(0).getCell(1, 0).getCellFormat();
      WritableCellFormat wc = new WritableCellFormat();
      // 设置居中
      wc.setAlignment(Alignment.CENTRE);
      // 设置边框线
//    wc.setBorder(Border.ALL, BorderLineStyle.THIN);
      wc.setBackground(jxl.format.Colour.GREEN);

      Label nc0 = new Label(0, 0, "标题1",wc);//Label(x,y,z)其中x代表单元格的第x+1列，第y+1行, 单元格的内容是z
      Label nc1 = new Label(1, 0, "标题2",wc);
      Label nc2 = new Label(2, 0, "标题3",wc);
      Label nc3 = new Label(0, 1, "dddd");
      Label nc4 = new Label(1, 1, "ffff");

      wsheet.addCell(nc0);
      wsheet.addCell(nc1);
      wsheet.addCell(nc2);
      wsheet.addCell(nc3);
      wsheet.addCell(nc4);

      return writableWorkbook;
    }
  }

最后贡献下相关的代码：SpringTest_jb51.rar

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