数据库工具类简单实现

package com.yunchow.util;

import java.sql.*;

/**
 * Jdbc tools
 * @author yunchow
 * @version 1.1  09/8/4
 */
public final class JdbcUtils {


	private static MyDataSource dataSource;
	// load database driver
	static {
		// 初始化数据源
		// System.out.println("初始化数据源");
		dataSource = new MyDataSource();
	}
	// to prevent from creating the JdbcUtils's instance
	private JdbcUtils(){

	}

	/**
	 * to get a database connection 
	 * @exception SQLException if cannot get a connection throws this 

exception
	 * @return database connection, or null if failed
	 */
	public static Connection getConnection() throws SQLException {
		try {
			// System.out.println("get Connection...");
			return dataSource.getConnection();
			// return DriverManager.getConnection

("jdbc:sqlserver://localhost:1433;databasename=addressbook","sa","123456");
		} catch (Exception ex) {
			throw new SQLException(ex.getMessage());
		}
	}
	// 关闭连接
	public static void close(Connection conn) {
		close(null, null, conn);
	}
	// 关闭连接,和stmt
	public static void close(Statement stmt, Connection conn) {
		close(null, stmt, conn);
	}
	/**
	 * to release database resource
	 * @param rs 结果集
	 * @param stmt 
	 * @param conn 数据库连接
	 */
	public static void close(ResultSet rs, Statement stmt, Connection 

conn) {
		try {
			if(rs != null) {
				rs.close();
				rs = null;
			}
		} catch (SQLException ex) {
			throw new RuntimeException(ex);
		}
		try {
			if(stmt != null) {
				stmt.close();
				stmt = null;
			}
		} catch (SQLException ex) {
			throw new RuntimeException(ex);
		}
		try {
			if(conn!=null && !conn.isClosed()) {
				conn.close();
			}
		} catch (SQLException ex) {
			throw new RuntimeException(ex);
		}
	}


}