oracle Blob对象的读写 (插入Blob)

 CREATE SEQUENCE  "ZW"."STUDENT_SEQ"  MINVALUE 1 MAXVALUE 999999999999999999999999999 INCREMENT BY 1 START WITH 81 CACHE 20 NOORDER  NOCYCLE ;

 

public class InsertImage extends HttpServlet {            //插入blob,先获取id  (id自增有个触发器给删除了)

 protected void doGet(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException {
  doPost(req,resp);
 }

 protected void doPost(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException {
  
  // String fileName="D:\\My Documents\\My Pictures\\colorjb33.bmp";
  int id=this.getId();                                //同一个id
  String name=req.getParameter("name");
  String fileName=req.getParameter("fileName");
   Blob b=null;
   int i=0;
   OracleConnection oc=new OracleConnection();
   Connection conn=oc.getConnection();
   try {
    String sql="insert into student(id,name,image) values(?,?,empty_blob())";
    
     PreparedStatement ps=conn.prepareStatement(sql);
     ps.setInt(1, id);
     ps.setString(2, name);
     i= ps.executeUpdate();
     ps.close();
     System.out.println("insert empty_blob");
   String sl="select image from student where id=? for update";
   PreparedStatement ps2=conn.prepareStatement(sl);
   ps2.setInt(1, id);
   ResultSet rs2=ps2.executeQuery();
   
   byte[] buf=new byte[1024];
   if(rs2.next()){
     b=rs2.getBlob("image");
     System.out.println(b);
     BufferedOutputStream bos=new BufferedOutputStream(b.setBinaryStream(0));
     BufferedInputStream bis=new BufferedInputStream(new FileInputStream(fileName));
     while(bis.read(buf)!=-1){
      bos.write(buf);
     }
     bos.close();
     bis.close();
   }
   rs2.close();
   ps2.close();
   conn.close();
   } catch (Exception e) {
    e.printStackTrace();
   }
  System.out.println("success.............");
 }
 private int getId(){
  int id=0;
  OracleConnection oc=new OracleConnection();
  Connection conn=oc.getConnection();
  String sql="select student_seq.nextval from dual";
  try {
   PreparedStatement ps=conn.prepareStatement(sql);
   
  ResultSet rs=ps.executeQuery();
  if(rs.next()){
   id=rs.getInt(1);
  }
   ps.close();
   conn.close();
  } catch (SQLException e) {
   e.printStackTrace();
  }
  return id;
 }
}