databaseaccess.java

这是一个工作流管理的后端EJB实现

package com.coshare.joyteam.util;

import java.sql.SQLException;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;

public class DatabaseAccess
{
	private Connection dbConnection = null;

	private DataSource dataSource = null;

	private Statement statement = null;

	private ResultSet resultset = null;

	public DatabaseAccess()
	{

	}

	/*
	 * getDataSource()
	 */
	public DataSource getDataSource()
	{
		try
		{
			String dataSourceURL = "java:/joyteamDS";
			Context context = new InitialContext();
			dataSource = (DataSource) context.lookup(dataSourceURL);
		}
		catch (NamingException e)
		{
			dataSource = null;
			e.printStackTrace();
		}

		return dataSource;
	}

	/*
	 * getConnection()
	 */
	public Connection getConnection()
	{
		this.getDataSource();
		if (dataSource != null)
		{
			try
			{
				String username = "";
				String password = "";
				dbConnection = dataSource.getConnection();
			}
			catch (SQLException e)
			{
				dbConnection = null;
				e.printStackTrace();
			}
		}
		else
		{
			dbConnection = null;
		}

		return dbConnection;
	}

	/*
	 * openConnection()
	 */
	public Connection openConnection()
	{
		String driverName = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
		String db_URL = "";
		String username = "";
		String password = "";
		
		try
		{
			Class.forName(driverName).newInstance();
			dbConnection = DriverManager.getConnection(db_URL, username, password);
		}
		catch (InstantiationException e)
		{
			dbConnection = null;
			e.printStackTrace();
		}
		catch (IllegalAccessException e)
		{
			dbConnection = null;
			e.printStackTrace();
		}
		catch (ClassNotFoundException e)
		{
			dbConnection = null;
			e.printStackTrace();
		}
		catch (SQLException e)
		{
			dbConnection = null;
			e.printStackTrace();
		}
		
		return dbConnection;

	}

	/*
	 * closeConnection()
	 */
	public void closeConnection()
	{
		if (dbConnection != null)
		{
			try
			{
				dbConnection.close();
			}
			catch (SQLException e)
			{
				e.printStackTrace();
			}
			finally
			{
				dbConnection = null;
			}
		}
	}

	/*
	 * createStatement()
	 */
	public Statement createStatement()
	{
		if (dbConnection != null)
		{
			try
			{
				statement = dbConnection.createStatement();
			}
			catch (SQLException e)
			{
				statement = null;
				e.printStackTrace();
			}
		}
		else
		{
			statement = null;
		}

		return statement;
	}
	
	/*
	 * prepareCall(String insqlStr)
	 */
	public CallableStatement prepareCall(String insqlStr)
	{
		if (dbConnection != null)
		{
			try
			{
				statement = dbConnection.prepareCall("{call" + insqlStr + "}");
			}
			catch (SQLException e)
			{
				e.printStackTrace();
				statement = null;
			}
		}
		else
		{
			statement = null;
		}
		
		return (CallableStatement)statement;
	}

	/*
	 * prepareStatement(String insqlStr)
	 */
	public PreparedStatement prepareStatement(String insqlStr)
	{
		if (dbConnection != null)
		{
			try
			{
				statement = dbConnection.prepareStatement(insqlStr);
			}
			catch (SQLException e)
			{
				statement = null;
				e.printStackTrace();
			}
		}
		else
		{
			statement = null;
		}
		
		return (PreparedStatement)statement;
	}

	/*
	 * closeStatement()
	 */
	public void closeStatement()
	{
		if (statement != null)
		{
			try
			{
				statement.close();
			}
			catch (SQLException e)
			{
				e.printStackTrace();
			}
			finally
			{
				statement = null;
			}
		}
	}
	

	/*
	 * sqlExecute(String insqlStr)
	 */
	public ResultSet sqlExecute(String insqlStr)
	{
		try
		{
			statement = dbConnection.createStatement();
			resultset = statement.executeQuery(insqlStr);
		}
		catch (SQLException e)
		{
			resultset = null;
			e.printStackTrace();
		}
		
		return resultset;
	}

	/*
	 * beginTransaction()
	 */
	public void beginTransaction()
	{
		if (dbConnection != null)
		{
			try
			{
				dbConnection.setAutoCommit(false);
			}
			catch (SQLException e)
			{
				e.printStackTrace();
			}
		}
	}

	/*
	 * commitTransaction()
	 */
	public void commitTransaction()
	{
		if (dbConnection != null)
		{
			try
			{
				dbConnection.commit();
			}
			catch (SQLException e)
			{
				e.printStackTrace();
			}
		}
	}
}