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