dbutil.java

很好的WebSphereCE轻量级J2EE服务器使用入门的范例程序

package com.ibm.db2.simplej2ee;

import java.sql.Connection;
import java.sql.SQLException;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;
import javax.xml.parsers.DocumentBuilder;

public class DBUtil
{	
	// use in J2EE server
	DataSource ds = null;
	DocumentBuilder docBuilder = null;
	
	public DBUtil()
	{
		InitialContext ctx;
		try
		{
			ctx = new InitialContext();
			ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MyDataSource");
			if (ds == null)
			{
				System.err.println("Datasource ds is null");
			}
		}
		catch (NamingException e)
		{
			System.err.println("Cannot find datasource");
			e.printStackTrace();
		}
	}
	
	/*
	 * Return a Connection object if connection is valid, null otherwise.
	 */
	public Connection getConnection()
	{
		try
		{
			Connection conn = ds.getConnection(); 
			if (conn == null)
			{
				System.err.println("getConnection: conn is null");
			}
			return conn;
		}
		catch (SQLException e)
		{
			// TODO Auto-generated catch block
			System.err.println("getConnection: Couldn't get a connection.");
			e.printStackTrace();
			return null;
		}
	}

	public void closeConnection(Connection con)
	{
		try
		{
			con.close();
		}
		catch (SQLException e)
		{
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	/*
	 * Clean and return string s used in XML query.
	 */
	public String cleanXQueryString(String s)
	{
		s = s.replaceAll("'", "\'\'");
		s = s.replaceAll("\\\\", "\\\\\\\\");
		s = s.replaceAll("\\$", "\\\\\\$");
		s = s.replaceAll("\\^", "\\\\\\\\^");
		s = s.replaceAll("\\|", "\\\\\\\\|");
		return s;
	}
}