Simple JDBC Dao for Oracle

This snippet shows how to connect to an Oracle database using JDBC. Open the connection, execute the query, get result set and close the connection.

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package com.livrona.snippets.dao;

import java.io.FileInputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
/**
 * This snippet shows how to connect to an Oracle database using JDBC. Open the
 * connection, execute the query, get result set and close the connection.
 */
publicclass OracleDao {
privatestatic String driverClass ="oracle.jdbc.driver.OracleDriver";

private Connection con;

private String url;
private String userName;
private String password;

/**
	 * Initialize the Dao
	 * 
	 * @param propertiesFile
	 * @throws IOException
	 * @throws ClassNotFoundException
	 */
publicvoid init(String propertiesFile) throws IOException,
			ClassNotFoundException {
// load the properties
		Properties props =new Properties();
		props.load(new FileInputStream(propertiesFile));

// get the properties
		url = props.getProperty("db.url");
		userName = props.getProperty("db.user");
		password = props.getProperty("db.password");

// load the class
		Class.forName(driverClass);
	}

/**
	 * Open the Dao Connection
	 * 
	 * @param fs
	 * @throws SQLException
	 * @throws IOException
	 */
publicvoid open() throws SQLException, IOException {

// get the connection to the database
		con = DriverManager.getConnection(url, userName, password);
	}

/**
	 * Close the connection
	 * 
	 * @throws SQLException
	 */
publicvoid close() throws SQLException {
if (con !=null) {
// close the connection
			con.close();
		}
	}

/**
	 * Get the Current Time via DB Query
	 * 
	 * @return
	 * @throws SQLException
	 * @throws IOException
	 */
public String getCurrentTime() throws SQLException, IOException {
		String dateTime =null;
		ResultSet rst = fetch("select SYSDATE from dual");
while (rst.next()) {
			dateTime = rst.getString(1);
		}
// close the resultset
		rst.close();
return dateTime;

	}

/**
	 * Fetch data
	 * 
	 * @throws SQLException
	 * @throws IOException
	 */
private ResultSet fetch(String sql) throws SQLException, IOException {
// create the prepared stmt
		PreparedStatement ps = con.prepareStatement(sql);

// execute the query
		ResultSet rs = ps.executeQuery();
		ps.close(); // close prepared statement
return rs;
	}

publicstaticvoid main(String[] args) throws Exception {
if (args.length !=1) {
			System.out
					.println("Usage: java com.livrona.snippets.dao.OracleDao <Path to your file>");
			System.exit(0);
		}

// store args
		String propertiesFile = args[0];
		System.out.println("File : "+ propertiesFile);

// execute the test functions
		OracleDao dao =new OracleDao();
		dao.init(propertiesFile);
		dao.open();
		dao.getCurrentTime();
		dao.close();
	}
}