fileupload上传文件存储到oracle Blob字段中

从网上查了许多资料，攒了个功能，暂且记下来，呵呵。需要apache的fileupload组件和io组件。

// 建立一个新的Upload对象  
DiskFileUpload upload = new DiskFileUpload();  
 
upload.setSizeThreshold(1024 * 300); //设置缓冲区大小
String rootPath = getServletConfig().getServletContext().getRealPath("/");  
upload.setRepositoryPath(rootPath+"//uploads");//设置缓冲区目录
upload.setSizeMax(10*1024*1024); //限制最大文件为10MB
 
FileItem item = null;
Connection conn = null; 
ResultSet rst = null;
PreparedStatement pstmt = null;
OutputStream output = null;
BufferedInputStream bi = null;
try{  
 List items = upload.parseRequest(request);  
 Iterator iter = items.iterator();
 while(iter.hasNext()){  
     item = (FileItem) iter.next();        
     
  if (!item.isFormField()){//（不是表单域）是文件对象
   bi = new BufferedInputStream(item.getInputStream());
      byte[] buffer = new byte[1024];           
   conn = JdbcUtilsHelper.getConnection();
   conn.setAutoCommit(false);
   //先清空原来的上传文件
   pstmt = conn.prepareStatement("update table set col=EMPTY_BLOB() where id=?");    
   pstmt.setString(1, xh);
   pstmt.execute();    
   pstmt.close();
   
   pstmt = conn.prepareStatement("select col from table  where id=? for update");
   pstmt.setString(1, xh);
   rst = pstmt.executeQuery();
   if(rst.next()){
    System.out.println("next");
    oracle.sql.BLOB blob = (oracle.sql.BLOB)rst.getBlob(1);     
    output = blob.setBinaryStream(0);
    int readNum = -1;
    while( (readNum = bi.read(buffer)) != -1){ //通过Oracle驱动使用流方式读写
     output.write(buffer,0,readNum);
    }
    //BLOB字段输出流关闭,以及其他GC处理
    bi.close();
    output.flush();
    output.close();
    conn.commit();
    
    rst.close();
    item.delete();     
   }
   conn.setAutoCommit(true);   
     } 
 }// end while
 rtnCode = "1";//保存成功
}catch(FileUploadException e) {// 处理文件尺寸过大异常   
    if(e instanceof SizeLimitExceededException) {   
     rtnCode = "-2";//文件太大 
 }   
    e.printStackTrace();   
}catch(Exception e){
 rtnCode = "-1";//保存失败
 e.printStackTrace();
}finally{
   if(rst != null){
    try{    
     rst.close();
  }catch(Exception e1){
   e1.printStackTrace();
  }
   }
   if(pstmt != null){
    try{    
     pstmt.close();
  }catch(Exception e1){
   e1.printStackTrace();
  }
    }
   if(conn != null){
    conn.setAutoCommit(true);
    try{    
   conn.close();
  }catch(Exception e1){
   e1.printStackTrace();
  }        
   }
   if(item != null){
    item.delete();
   }    
}// end finally