Using the org.apache.derby.jdbc.ClientDriver driver to access the
Derby database through network, the driver is writting all the file into memory
(RAM) before sending
it to the database.
Writting small files (smaller than 5Mo) into the database works fine,
but it is impossible to write big files (40Mo for example, or more), without
getting the
exception java.lang.OutOfMemoryError.
The org.apache.derby.jdbc.EmbeddedDriver doesn't have this problem.
Here follows some code that creates a database, a table, and trys to write a
BLOB. 2 parameters are to be changed for the code to work for you :
DERBY_DBMS_PATH and FILE
import NetNoLedge.Configuration.Configs;
import org.apache.derby.drda.NetworkServerControl;
import java.net.InetAddress;
import java.io.*;
import java.sql.*;
/**
*
* @author greg
*/
public class DerbyServer_JDBC_BLOB_test {
// The unique instance of DerbyServer in the application.
private static DerbyServer_JDBC_BLOB_test derbyServer;
private NetworkServerControl server;
private static final String DERBY_JDBC_DRIVER = "org.apache.derby.jdbc.ClientDriver";
private static final String DERBY_DATABASE_NAME = "Test";
// ###############################################################
// ############### SET HERE THE EXISTING PATH YOU WANT ################
// ###############################################################
private static final String DERBY_DBMS_PATH = "/home/greg/DatabaseTest";
// ###############################################################
// ###############################################################
private static int derbyPort = 9157;
private static String userName = "user";
private static String userPassword = "password";
// ###################################################################################
// ############# DEFINE HERE THE PATH TO THE FILE YOU WANT TO WRITE INTO THE
DATABASE ###########
// ############# TRY A 100kb-3Mb FILE, AND AFTER A 40Mb OR BIGGER FILE
#########################
//
###################################################################################
private static final File FILE = new File("/home/greg/01.jpg");
//
###################################################################################
//
###################################################################################
/**
* <p>Used to test the server.
*/
public static void main(String args[]) {
try {
DerbyServer_JDBC_BLOB_test.launchServer();
DerbyServer_JDBC_BLOB_test server = getUniqueInstance();
server.start();
System.out.println("Server started");
// After the server has been started, launch a first connection to the database to
// 1) Create the database if it doesn't exist already,
// 2) Create the tables if they don't exist already.
Class.forName(DERBY_JDBC_DRIVER).newInstance();
Connection connection = DriverManager.getConnection
("jdbc:derby://localhost:"+derbyPort+"/"+DERBY_DATABASE_NAME+";create=true",
userName, userPassword);
System.out.println("Network JDBC connection to Derby succeded. Database
created if not created already.");
Statement statement = connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
Statement statement2;
// Create the table "file" if it doesn't already exist.
String [] tableNames={"file"};
boolean exist;
String currentTable;
ResultSet result = statement.executeQuery("SELECT TABLENAME FROM
SYS.SYSTABLES");
for (int i=0;i<tableNames.length;i++) {
exist=false;
while (result.next()){
if (tableNames[i].equalsIgnoreCase(result.getString(1)))
exist=true;
}
if (!exist) {
statement2 = connection.createStatement();
statement2.execute("CREATE TABLE file (" +
"file BLOB(2G) NOT NULL)");
connection.commit();
}
result.beforeFirst();
}
System.out.println("Table file created if not created already");
System.out.println("File insertion into BLOB");
FileInputStream inputStream = new FileInputStream(FILE);
PreparedStatement preparedStatement =
connection.prepareStatement("INSERT INTO file(file) VALUES (?)");
preparedStatement.setBinaryStream(1,inputStream,(int) FILE.length());
preparedStatement .execute();
connection.commit();
System.out.println("File inserted into BLOB");
}
catch (Exception e) {
e.printStackTrace();
}
}
/** Creates a new instance of MckoiServer
* Password is used at the database creation. It will be the database
password once created.
*/
private DerbyServer_JDBC_BLOB_test() throws Exception {
System.setProperty("derby.system.home", DERBY_DBMS_PATH);
// Set the server to request an authentification.
System.setProperty("derby.authentication.provider", "BUILTIN");
System.setProperty("derby.connection.requireAuthentication", "true");
// Create a user that can connect to Derby.
System.setProperty("derby.user."+userName, userPassword);
// Set Derby to grant full access to the created user (to all the databases).
System.setProperty("derby.database.fullAccessUsers", userName);
//System.setProperty("derby.system.bootAll", "true");
// See if the 9157 port is already taken.
// Change it if necessary.
boolean isPortFree = false;
while ( !isPortFree ) {
try {
java.net.ServerSocket serverTest = new
java.net.ServerSocket(derbyPort);
serverTest.close();
serverTest = null;
isPortFree = true;
}
catch (Exception e) {
System.out.println("Port already in use : "+derbyPort);
derbyPort++;
System.out.println("Try with port "+derbyPort);
}
}
server = new NetworkServerControl(InetAddress.getByName("localhost"),derbyPort);
}
public static void launchServer() throws Exception {
derbyServer = new DerbyServer_JDBC_BLOB_test();
}
public static DerbyServer_JDBC_BLOB_test getUniqueInstance() {
return derbyServer;
}
/**
* <p>Start the server.
*/
public void start() {
try {
server.start(null);
}
catch (Exception e) {
e.printStackTrace(System.err);
}
}
/**
* <p>Stop the server.
*/
public void stop() {
try {
server.shutdown();
}
catch (Exception e) {
e.printStackTrace(System.err);
}
}
}
