oracle Blob对象的读写

select student_seq.nextval from dual // 每执行一次都不一样（不管数据库插没插入数据）

 

public class OracleConnection {
 String url="jdbc:oracle:thin:@localhost:1521:orcl";
 String user="zw";
 String password="pass";
 
 public Connection getConnection(){
  Connection conn=null;
  try {
   Driver.class.forName("oracle.jdbc.driver.OracleDriver");
  } catch (ClassNotFoundException e) {
   e.printStackTrace();
  }
  try {
   conn=DriverManager.getConnection(url,user,password);
  } catch (SQLException e) {
   e.printStackTrace();
  }
  return conn;
 }

}

 

public class ShowImageServlet extends HttpServlet  {//读Blob

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

 protected void doPost(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException {
  OracleConnection oc=new OracleConnection();
  Connection conn=oc.getConnection();
  OutputStream out=resp.getOutputStream();
  String sl="select image from student where id=16 ";// image 类型Blob
  PreparedStatement ps2;
  try {
   ps2 = conn.prepareStatement(sl);
   ResultSet rs2=ps2.executeQuery();
   Blob b=null;
   byte[] buf=new byte[1024];
   BufferedOutputStream bos=null;
   BufferedInputStream bis=null;
   if(rs2.next()){
     b=rs2.getBlob("image");
     bis=new BufferedInputStream(b.getBinaryStream());
    while(bis.read(buf)!=-1){
     out.write(buf);
     out.flush();
    }
    bis.close();
   }
   rs2.close();
   ps2.close();
   conn.close();
   out.close();
  } catch (SQLException e) {
   e.printStackTrace();
  }
 }
}

 

------------------------------------------------------------------------

public int updateBlob(){        //插入Blob
  int i=-1;
  Blob b=null;
  OracleConnection oc=new OracleConnection();
  Connection conn=oc.getConnection();
  try {
  String sl="select image from student where id=47 for update";
  PreparedStatement ps2=conn.prepareStatement(sl);
  ResultSet rs2=ps2.executeQuery();
  //System.out.println(rs2.next());
  
  byte[] buf=new byte[1024];
  if(rs2.next()){
    b=rs2.getBlob("image");  //数据库初始为empty_blob();
    System.out.println(b);
    BufferedOutputStream bos=new BufferedOutputStream(b.setBinaryStream(0));
    BufferedInputStream bis=new BufferedInputStream(new FileInputStream(fileName));//blob对象
   
    while(bis.read(buf)!=-1){
     bos.write(buf);                     //blob对象保存到数据库
    }
    bos.close();
    bis.close();
  }
  rs2.close();
  ps2.close();
  
   conn.close();
  } catch (Exception e) {
   e.printStackTrace();
  }
  return i;
 }

 

------------------------------------------------------------------------------------

Clob对象的插入：（对照上面的需要更改的地方：）

     BufferedWriter bos=new BufferedWriter(b.setCharacterStream(0));
     BufferedReader bis=new BufferedReader(new FileReader(fileName));

 

     char[] buf=new char[1024];

     String sql="insert into student(id,name,comm) values(?,?,empty_clob())";

     Clob b=null;

 http://hi.baidu.com/%C1%F5%D0%A1%BB%A2%C1%F5/blog/item/28ddd2c75cc93fd6d0006076.html