java_JdbcUtilis_单实例

//eg1,没有使用单实例，eg2有

 

 

package cn.itcast;



import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;



public final class JdbcUtils {



	private static String url = "jdbc:mysql://localhost:/xxxx";

	private static String user = "";

	private static String password = "";



	private JdbcUtils() {

	}



	static {

		try {

			Class.forName("com.mysql.jdbc.Driver");

		} catch (ClassNotFoundException e) {

			// TODO Auto-generated catch block

			throw new ExceptionInInitializerError(e);

		}

	}



	public static Connection getConnection() throws SQLException {

		return DriverManager.getConnection(url, user, password);

	}



	public static void free(ResultSet rs, Statement st, Connection conn) {

		try {

			if (rs != null)

				rs.close();

		} catch (SQLException e) {

			e.printStackTrace();

		} finally {

			try {

				if (st != null)

					st.close();

			} catch (SQLException e) {

				e.printStackTrace();

			} finally {

				if (conn != null)

					try {

						conn.close();

					} catch (SQLException e) {

						e.printStackTrace();

					}

			}

		}

	}

}