JDBC连接MySQL数据库

package com.digican.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class SQLdb {

	private static String user = "root";
	private static String password = "root";
	private static String url = "jdbc:mysql://127.0.0.1:3306/mysql";
	
	private static SQLdb instance = null;

	private SQLdb() {
	}

	public static SQLdb getInstance() {
		if (instance == null) {
			synchronized (SQLdb.class) {
				if (instance == null) {
					instance = new SQLdb();
				}
			}
		}
		return instance;
	}
	
	/**
	 * 自动加载MySQL数据库驱动
	 */
	static{
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			System.out.println("未找到MySQL驱动...");
			e.printStackTrace();
		}
	}
	
	public Connection getConnection() throws SQLException {
		return DriverManager.getConnection(url, user, password);
	}

	public static void free(ResultSet rs, PreparedStatement ps, Connection conn) {
		try {
			if (rs != null)
				rs.close();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			try {
				if (ps != null)
					ps.close();
			} catch (SQLException e) {
				e.printStackTrace();
			} finally {
				if (conn != null){
					try {
						conn.close();
					} catch (SQLException e) {
						e.printStackTrace();
					}
				}
			}
		}
	}
}