Excel文件使用Http服务实现下载

1. Excel文件使用Http服务实现下载

1.1. 在web.xml文件中注册新建的Servlet

    <!-- ExcelDownloadServlet -->

    <servlet>

        <servlet-name>excelDownloadServlet</servlet-name>

        <servlet-class>

            com.jerry.support.ExcelDownloadServlet

        </servlet-class>

        <load-on-startup>5</load-on-startup>

    </servlet>

    <servlet-mapping>

        <servlet-name>excelDownloadServlet</servlet-name>

        <url-pattern>/excelDownloadServlet</url-pattern>

    </servlet-mapping>

1.2. 创建ExcelDownloadServlet.java类，在容器中查找相应service服务，使用service服务去完成预定的任务

public class ExcelDownloadServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

   

    IExcelService iEexcelService = ServiceLocator.getInstance().getService("iEexcelService");

       

        response.reset();   // 重置response

        response.setContentType("application/msexcel;charset=\"UTF-8\"");

        response.setHeader("Content-disposition","attachment; filename=IndexModelExcel.xls");

       

        BufferedInputStream in = null;

        BufferedOutputStream out = null;

        try {                      

            String path = iEexcelService.downloadTemplate(request);

            PathUtils utils = new PathUtils();

            File file = new File(utils.getWebRoot() + path);

            in = new BufferedInputStream(new FileInputStream(file));

            out = new BufferedOutputStream(response.getOutputStream());

           

            byte[] buff = new byte[1024];

            while (-1 != in.read(buff)) {

                out.write(buff);

                buff = new byte[1024]; // 需要扩充字符数组

            }

           

            try {

                if (null != in)

                    in.close();

                if (null != out)

                    out.close();

            } catch (IOException e) {

                e.printStackTrace();

            }

            response.flushBuffer();

        } catch (IllegalAccessException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

   

    public void doPost(HttpServletRequest request, HttpServletResponse response) {

        this.doGet(request, response);

    }

}

 

request.getRequestURL():http://200.200.202.189:8081/project /excelDownloadServlet

request.getContextPath():/project

url: http://200.200.202.189:8081/visu/IndexExcel.xls

 

 

1.3.Web工程路径Utils

public class PathUtils {

 

  /**

   * 获取工程类路径（绝对路径）

   *

   * @return

   */

  public String getWebClassesPath() {

      String path = getClass().getProtectionDomain().getCodeSource().getLocation().getPath();

      return path;

  }

 

  /**

   * 获取WEB-INF文件夹路径（绝对路径）

   *

   * @return

   * @throws IllegalAccessException

   */

  public String getWebInfPath() throws IllegalAccessException{

     String path = getWebClassesPath();

     if (path.indexOf("WEB-INF") > 0) {

         path = path.substring(0, path.indexOf("WEB-INF")+8);

     } else {

         throw new IllegalAccessException("路径获取错误");

     }

     return path;

  }

 

  /**

   * 获取WebRoot文件夹路径（绝对路径）

   *

   * @return

   * @throws IllegalAccessException

   */

  public String getWebRoot() throws IllegalAccessException{

     String path = getWebClassesPath();

     if (path.indexOf("WEB-INF") > 0) {

         path = path.substring(0, path.indexOf("WEB-INF/classes"));

     } else {

         throw new IllegalAccessException("路径获取错误");

     }

     return path;

  }

 

  public static void main(String[] args) throws Exception {

      PathUtils utils = new PathUtils();

      System.out.println("1、" + utils.getWebClassesPath());

      System.out.println("2、" + utils.getWebInfPath());

      System.out.println("3、" + utils.getWebRoot());

  }

 

}

 

 

输出：1、/E:/Workspaces/MyEclipse/project/WebRoot/WEB-INF/classes/

2、/E:/Workspaces/MyEclipse/project/WebRoot/WEB-INF/

          3、/E:/Workspaces/MyEclipse/project/WebRoot/

 

1.4. 浏览器远程调用servlet在服务器端生成Excel文件，发生乱码及无法打开Excel文件的问题是因为在生成Excel文件时没有指定文件的编码格式，采用UTF-8的格式

                    File file = new File(realPath);

    file.createNewFile();

    FileOutputStream fos = new FileOutputStream(file);

            OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF-8");

            osw.write(excelXml);

            osw.flush();

            fos.close();