以上是转贴的一个关于大数据存储的方法在Oracle中
假定有一张表
lob_table(blob_col Blob, clob_col clob)
假定你创建了Statement Object, stmt// Select LOB locator into standard result set.
ResultSet rs =
stmt.executeQuery ("SELECT blob_col, clob_col FROM lob_table");
while (rs.next())
{
// Get LOB locators into Java wrapper classes.
java.sql.Blob blob = (java.sql.Blob)rs.getObject(1);
java.sql.Clob clob = (java.sql.Clob)rs.getObject(2);
(...process...)
}输出强制转换为java.sql.Blob 和 java.sql.Clob，
你接下来可以强制转换成oracle.sql.BLOB 和 CLOB,以便利用 oracle.sql.* 中class的扩展功能，你可以这样转换 // Get LOB locators into Java wrapper classes.
oracle.sql.BLOB blob = (BLOB)rs.getObject(1);
oracle.sql.CLOB clob = (CLOB)rs.getObject(2);
(...process...)
假定有一张表
lob_table(blob_col Blob, clob_col clob)
假定你创建了Statement Object, stmt// Select LOB locator into standard result set.
ResultSet rs =
stmt.executeQuery ("SELECT blob_col, clob_col FROM lob_table");
while (rs.next())
{
// Get LOB locators into Java wrapper classes.
java.sql.Blob blob = (java.sql.Blob)rs.getObject(1);
java.sql.Clob clob = (java.sql.Clob)rs.getObject(2);
(...process...)
}输出强制转换为java.sql.Blob 和 java.sql.Clob，
你接下来可以强制转换成oracle.sql.BLOB 和 CLOB,以便利用 oracle.sql.* 中class的扩展功能，你可以这样转换 // Get LOB locators into Java wrapper classes.
oracle.sql.BLOB blob = (BLOB)rs.getObject(1);
oracle.sql.CLOB clob = (CLOB)rs.getObject(2);
(...process...)
// %oracle 目录%\jdbc\demo\samples\generic
/*
* This sample demonstrate basic Lob support.
* (insert, fetch rows of BLOB and CLOB)
*
* It 1. drops, create, and populates table basic_lob_table
* with blob, clob data types in the database.
* 2. Please use jdk1.2 or later version and classes12.zip
*/import java.sql.*;
import java.io.*;
import java.util.*;// Importing the Oracle Jdbc driver package makes
// the code more readable
import oracle.jdbc.*;//needed for new CLOB and BLOB classes
import oracle.sql.*;public class LobExample
{
public static void main (String args [])
throws Exception
{
// Register the Oracle JDBC driver
DriverManager.registerDriver
(new oracle.jdbc.OracleDriver()); String url = "jdbc:oracle:oci8:@";
try {
String url1 = System.getProperty("JDBC_URL");
if (url1 != null)
url = url1;
} catch (Exception e) {
// If there is any security exception, ignore it
// and use the default
} // Connect to the database
Connection conn =
DriverManager.getConnection (url, "hr", "hr"); // It's faster when auto commit is off
conn.setAutoCommit (false); // Create a Statement
Statement stmt = conn.createStatement (); try
{
stmt.execute ("drop table basic_lob_table");
}
catch (SQLException e)
{
// An exception could be raised here if the
// table did not exist already.
} // Create a table containing a BLOB and a CLOB
stmt.execute ("create table basic_lob_table (x varchar2 (30), " +
"b blob, c clob)");
// Populate the table
stmt.execute ("insert into basic_lob_table values ('one', " +
"'010101010101010101010101010101', " +
"'onetwothreefour')");
stmt.execute ("insert into basic_lob_table values ('two', " +
"'0202020202020202020202020202', " +
"'twothreefourfivesix')");
System.out.println ("Dumping lobs"); // Select the lobs. Since the Lob contents will be modified,
// we need to lock the table rows. This can be done by doing
// "select ... for update", but we don't need to select for
// update here because we have "autocommit" turned off and
// the previous "create table" statement already have the
// whole table locked.
ResultSet rset = stmt.executeQuery
("select * from basic_lob_table");
while (rset.next ())
{
// Get the lobs
BLOB blob = ((OracleResultSet)rset).getBLOB (2);
CLOB clob = ((OracleResultSet)rset).getCLOB (3); // Print the lob contents
dumpBlob (blob);
dumpClob (clob); // Change the lob contents
fillClob (clob, 2000);
fillBlob (blob, 4000);
} System.out.println ("Dumping lobs again"); rset = stmt.executeQuery
("select * from basic_lob_table");
while (rset.next ())
{
// Get the lobs
BLOB blob = ((OracleResultSet)rset).getBLOB (2);
CLOB clob = ((OracleResultSet)rset).getCLOB (3); // Print the lobs contents
dumpBlob (blob);
dumpClob (clob);
}
// Close all resources
rset.close();
stmt.close();
conn.close();
} // Utility function to dump Clob contents
static void dumpClob (CLOB clob)
throws Exception
{
// get character stream to retrieve clob data
Reader instream = clob.getCharacterStream(); // create temporary buffer for read
char[] buffer = new char[10]; // length of characters read
int length = 0; // fetch data
while ((length = instream.read(buffer)) != -1)
{
System.out.print("Read " + length + " chars: "); for (int i=0; i<length; i++)
System.out.print(buffer[i]);
System.out.println();
} // Close input stream
instream.close();
} // Utility function to dump Blob contents
static void dumpBlob (BLOB blob)
throws Exception
{
// Get binary output stream to retrieve blob data
InputStream instream = blob.getBinaryStream(); // Create temporary buffer for read
byte[] buffer = new byte[10]; // length of bytes read
int length = 0; // Fetch data
while ((length = instream.read(buffer)) != -1)
{
System.out.print("Read " + length + " bytes: "); for (int i=0; i<length; i++)
System.out.print(buffer[i]+" ");
System.out.println();
} // Close input stream
instream.close();
} // Utility function to put data in a Clob
static void fillClob (CLOB clob, long length)
throws Exception
{
Writer outstream = clob.getCharacterOutputStream(); int i = 0;
int chunk = 10; while (i < length)
{
outstream.write(i + "hello world", 0, chunk); i += chunk;
if (length - i < chunk)
chunk = (int) length - i;
}
outstream.close();
} // Utility function to put data in a Blob
static void fillBlob (BLOB blob, long length)
throws Exception
{
OutputStream outstream =
blob.getBinaryOutputStream(); int i = 0;
int chunk = 10; byte [] data = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; while (i < length)
{
data [0] = (byte)i;
outstream.write(data, 0, chunk); i += chunk;
if (length - i < chunk)
chunk = (int) length - i;
}
outstream.close();
}
}
DriverManager则没有问题