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OAF_文件系列1_实现OAF文件上传和下载MessageFileUpload/MessageDownload（案例）

20150707 Created By BaoXinjian

一、摘要

1. 文件上传

首先建立用于存放附件的临时视图对象(View Object)，包含Blob类型的视图属性(View Attribute)，建立页面包含messageFileUpload类型的Item，并创建页面的控制器。

2. 文件下载

这里要实现的功能是当单击附件链接时，能自动打开附件保存对话框.

二、文件上传

1. 创建messageFileUpload空间，其类型为BLOB

2. 创建CO实现方法

作用1. 数据保存至VO Blob中

作用2. 将VO中Blob数据保存至server上

  public void processFormRequest(OAPageContext pageContext, OAWebBean webBean) {   super.processFormRequest(pageContext, webBean);        EmpManageAMImpl empAM = (EmpManageAMImpl) pageContext.getApplicationModule(webBean);      if ("upload".equals(pageContext.getParameter(EVENT_PARAM))) {         try {           EmployeeFilesVOImpl empfilevo = empAM.getEmployeeFilesVO();           EmployeeFilesVORowImpl empfilerow = (EmployeeFilesVORowImpl) empfilevo.getCurrentRow();           BlobDomain blob = (BlobDomain) empfilerow.getEmployeeFile();           InputStream instream = blob.getBinaryStream();                      File directory = new File("/u2/VIS/visappl/gavin/files");            if(!directory.exists()) {             directory.mkdirs();             }           String filename = empfilerow.getFileId().toString()+".txt";           File file = new File (directory + filename);           FileOutputStream outstream = new FileOutputStream(file);                      int size = blob.getBufferSize();           byte[] buffer = new byte[size];           int length = 0;           while ((length = instream.read(buffer)) != -1) {             outstream.write(buffer, 0, length);           }                      instream.close();           outstream.flush();           outstream.close();                      empAM.getOADBTransaction().commit();         }catch(IOException ex) {           empAM.getOADBTransaction().rollback();           ex.printStackTrace();         }      }    }

三、文件下载

1. 创建一个MessageDown类型的空间，其会将附件显示在页面之上

2. 创建CO方法，将数据中的Blob数据通过或response保存至本地

  public void processFormRequest(OAPageContext pageContext, OAWebBean webBean) {   super.processFormRequest(pageContext, webBean);        EmpManageAMImpl empAM = (EmpManageAMImpl) pageContext.getApplicationModule(webBean);      if ("download".equals(pageContext.getParameter(EVENT_PARAM))) {         try {           EmployeeFilesVOImpl empfilevo = empAM.getEmployeeFilesVO();           EmployeeFilesVORowImpl empfilerow = (EmployeeFilesVORowImpl) empfilevo.getCurrentRow();           BlobDomain blob = (BlobDomain) empfilerow.getEmployeeFile();           InputStream instream = blob.getBinaryStream();                      HttpServletResponse response = (HttpServletResponse) pageContext.getRenderingContext().getServletResponse();           response.addHeader("Content-Disposition", "attachment;filename="+ "gavin.txt");           response.setContentType("application/x-msdownload");            int size = blob.getBufferSize();           byte[] buffer = new byte[size];           int length = 0;            while ((length = instream.read(buffer)) != -1) {             response.getOutputStream().write(buffer,0,length);           }           instream.close();           response.getOutputStream().flush();           response.getOutputStream().close();            empAM.getOADBTransaction().commit();         }catch(IOException ex) {           empAM.getOADBTransaction().rollback();           ex.printStackTrace();         }      } }