Using Oracle BLOBs in Java

LOB (Large Object) in Oracle Oracle can store very large data (possibly 4GB) so that it can be written to the database by serializing a file or any other object into a byte output stream (OutputStream) and then using the byte input stream ( InputStream) reads the data and deserializes it into the original file or object. Operation requires the use of Oracle's JDBC package, which extends the Blob objects in the Sun's JDBC package. At the same time need to pay attention to some details. The following code shows how to use a blob (a JDBC package in an instance that requires Oracle).

Import Oracle.jdbc.OracleResultSet; Using Oracle's ResultSet object
Import Oracle.sql.BLOB; Use Oracle's Blob object, not Sun's blob

...

try{
Connection conn=< Database Connection >;
File file=< to the database object >;
Conn.setautocommit (FALSE); To cancel the auto commit property of a Connection object
String File_name=file.getname ();

There is an item table in the database, where the file_name (VARCHAR2) store file name, File_blob (BLOB) stores the file object
String sql= "INSERT into item (FILE_NAME,FILE_BLOB) VALUES (' + file_name +" ', Empty_blob ()) "; Use "Empty_blob ()" To give birth to an empty BLOB
Statement stmt=conn.createstatement ();
int count=stmt.executeupdate (SQL);

Sql= "Select File_blob from Item WHERE iid= '" + IID + "' for UPDATE"; Use ' for UPDATE ' to get a write lock on a table
ResultSet rs=stmt.executequery (SQL);
Rs.next ();
BLOB blob= ((oracleresultset) RS). GetBlob ("File_blob"); Get Blob Object
OutputStream Out=blob.getbinaryoutputstream (); Create an output stream
InputStream in=new fileinputstream (file); Create an input stream
int size=blob.getbuffersize ();
Byte[] Buffer=new byte[size]; Create buffer
int Len;
while ((Len=in.read (buffer))!=-1)
Out.write (Buffer,0,len);
In.close ();
Out.close ();

Conn.commit ();
}
catch (Exception ex) {
try{
Conn.rollback ();
}
catch (SQLException Sqle) {
System.err.println (Sqle.getmessage ());
}
}

If you want to read out the file, just call the Blob's Getbinarystream () to generate an input stream, and then write a file.