对oracle的blob字段的操作（插入，更新，删除）

CREATE TABLE txjblob

(

x NUMBER(5) NOT NULL,

b BLOB DEFAULT EMPTY_BLOB() NOT NULL

)

插入：

   stmt.executeUpdate("insert into txjblob values(1,EMPTY_BLOB())");

   ResultSet rs = stmt.executeQuery("SELECT b FROM fff WHERE x=1 FOR UPDATE NOWAIT");

   FileInputStream fin = new FileInputStream("c:chart.gif");

   byte[] blobBuf = new byte[(int)fin.available()];

   fin.read(blobBuf);

   fin.close();

   if(rs.next()) {

    System.out.println(blobBuf.length);

    BLOB blob = (oracle.sql.BLOB)rs.getBlob(1);

    OutputStream out = blob.getBinaryOutputStream();

    out.write(blobBuf);

    out.close();

    conn.commit();

   }

更新：

   stmt.executeUpdate("UPDATE txjblob SET b=EMPTY_BLOB() WHERE x=1");

   ResultSet rs = stmt.executeQuery("SELECT b FROM fff WHERE x=1 FOR UPDATE NOWAIT");

   FileInputStream fin = new FileInputStream("c:chart.gif");

   byte[] blobBuf = new byte[(int)fin.available()];

   fin.read(blobBuf);

   fin.close();

   if(rs.next()) {

    System.out.println(blobBuf.length);

    BLOB blob = (oracle.sql.BLOB)rs.getBlob(1);

    OutputStream out = blob.getBinaryOutputStream();

    out.write(blobBuf);

    out.close();

    conn.commit();

   }

删除：

stmt.executeUpdate("DELETE txjblob WHERE x=1");

读取：

   ResultSet rs = stmt.executeQuery("select b from fff where x=1");

   if(rs.next()){

    BLOB blob = (BLOB)rs.getBlob(1);

    InputStream is = blob.getBinaryStream();

 //   InputStream is = rs.getBinaryStream(1);

    FileOutputStream os = new FileOutputStream("c:1.gif");

    int b;

    byte[] buffer = new byte[1024];

    while( (b=is.read(buffer)) != -1){

     os.write(buffer,0,b);

    }

    is.close();

    os.close();

   }