Ans)
The following steps allows you to use DBCP connection Pool in Hibernate .
Step 1:
Configure you Hibernate Properties as follows .
In Hiberante Properties file or XML file you need to use dbcp Connection API as follows.
hibernate.dialect org.hibernate.dialect.OracleDialect
hibernate.connection.driver_class oracle.jdbc.driver.OracleDriver
hibernate.connection.url jdbc:oracle:thin:@HostName:1522:DBName
hibernate.connection.username sa
hibernate.connection.password yourPassword
hibernate.connection.pool_size 5
hibernate.dbcp.poolPreparedStatements true
#hibernate.dbcp.ps.maxActive
hibernate.connection.provider_class com.salesorder.DBCPConnectionProvider
Step 2 :
Create your own Connection Provider by using DBCP as follows.
import java.io.PrintWriter;
import java.io.StringWriter;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.Properties;
import org.apache.commons.dbcp.BasicDataSource;
import org.apache.commons.dbcp.BasicDataSourceFactory;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.HibernateException;
import org.hibernate.cfg.Environment;
import org.hibernate.connection.ConnectionProvider;
import org.hibernate.connection.ConnectionProviderFactory;
public class DBCPConnectionProvider implements ConnectionProvider {
private static final Log log = LogFactory.getLog(DBCPConnectionProvider.class);
private static final String PREFIX = "hibernate.dbcp.";
private BasicDataSource ds;
// Old Environment property for backward-compatibility (property removed in Hibernate3)
private static final String DBCP_PS_MAXACTIVE = "hibernate.dbcp.ps.maxActive";
// Property doesn't exists in Hibernate2
private static final String AUTOCOMMIT = "hibernate.connection.autocommit";
public void configure(Properties props) throws HibernateException {
try {
log.debug("Configure DBCPConnectionProvider");
// DBCP properties used to create the BasicDataSource
Properties dbcpProperties = new Properties();
// DriverClass & url
String jdbcDriverClass = props.getProperty(Environment.DRIVER);
String jdbcUrl = props.getProperty(Environment.URL);
dbcpProperties.put("driverClassName", jdbcDriverClass);
dbcpProperties.put("url", jdbcUrl);
// Username / password
String username = props.getProperty(Environment.USER);
String password = props.getProperty(Environment.PASS);
dbcpProperties.put("username", username);
dbcpProperties.put("password", password);
// Isolation level
String isolationLevel = props.getProperty(Environment.ISOLATION);
if ((isolationLevel != null) && (isolationLevel.trim().length() > 0)) {
dbcpProperties.put("defaultTransactionIsolation", isolationLevel);
}
// Turn off autocommit (unless autocommit property is set)
String autocommit = props.getProperty(AUTOCOMMIT);
if ((autocommit != null) && (autocommit.trim().length() > 0)) {
dbcpProperties.put("defaultAutoCommit", autocommit);
} else {
dbcpProperties.put("defaultAutoCommit", String.valueOf(Boolean.FALSE));
}
// Pool size
String poolSize = props.getProperty(Environment.POOL_SIZE);
if ((poolSize != null) && (poolSize.trim().length() > 0)
&& (Integer.parseInt(poolSize) > 0)) {
dbcpProperties.put("maxActive", poolSize);
}
// Copy all "driver" properties into "connectionProperties"
Properties driverProps = ConnectionProviderFactory.getConnectionProperties(props);
if (driverProps.size() > 0) {
StringBuffer connectionProperties = new StringBuffer();
for (Iterator iter = driverProps.keySet().iterator(); iter.hasNext();) {
String key = (String) iter.next();
String value = driverProps.getProperty(key);
connectionProperties.append(key).append('=').append(value);
if (iter.hasNext()) {
connectionProperties.append(';');
}
}
dbcpProperties.put("connectionProperties", connectionProperties.toString());
}
// Copy all DBCP properties removing the prefix
for (Iterator iter = props.keySet().iterator() ; iter.hasNext() ;) {
String key = String.valueOf(iter.next());
if (key.startsWith(PREFIX)) {
String property = key.substring(PREFIX.length());
String value = props.getProperty(key);
dbcpProperties.put(property, value);
}
}
// Backward-compatibility
if (props.getProperty(DBCP_PS_MAXACTIVE) != null) {
dbcpProperties.put("poolPreparedStatements", String.valueOf(Boolean.TRUE));
dbcpProperties.put("maxOpenPreparedStatements", props.getProperty(DBCP_PS_MAXACTIVE));
}
// Some debug info
if (log.isDebugEnabled()) {
log.debug("Creating a DBCP BasicDataSource with the following DBCP factory properties:");
StringWriter sw = new StringWriter();
dbcpProperties.list(new PrintWriter(sw, true));
log.debug(sw.toString());
}
// Let the factory create the pool
ds = (BasicDataSource) BasicDataSourceFactory.createDataSource(dbcpProperties);
// The BasicDataSource has lazy initialization
// borrowing a connection will start the DataSource
// and make sure it is configured correctly.
Connection conn = ds.getConnection();
conn.close();
// Log pool statistics before continuing.
logStatistics();
}
catch (Exception e) {
String message = "Could not create a DBCP pool";
log.fatal(message, e);
if (ds != null) {
try {
ds.close();
}
catch (Exception e2) {
// ignore
}
ds = null;
}
throw new HibernateException(message, e);
}
log.debug("Configure DBCPConnectionProvider complete");
}
public Connection getConnection() throws SQLException {
Connection conn = null;
try {
//log.warn(" Get connection called");
conn = ds.getConnection();
}
finally {
logStatistics();
}
return conn;
}
public void closeConnection(Connection conn) throws SQLException {
try {
conn.commit(); //Test ***********
conn.close();
//log.warn("Is Connection closed "+conn.isClosed());
}
catch(Exception e) {
e.printStackTrace();
log.warn("Error While commit/close concetion",e);
if(!conn.isClosed())
{
log.warn("check point in dbcp 1");
conn.close();
}
}
finally {
if(!conn.isClosed()) {
log.warn("check point in dbcp 2");
conn.close();
}
logStatistics();
}
}
public void close() throws HibernateException {
try {
if (ds != null) {
ds.close();
ds = null;
}
else {
log.warn("Cannot close DBCP pool (not initialized)");
}
}
catch (Exception e) {
throw new HibernateException("Could not close DBCP pool", e);
}
log.debug("Close DBCPConnectionProvider complete");
}
public boolean supportsAggressiveRelease() {
return true; //It was false ****************
}
}
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