工具类

package cn.itcast.jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import cn.itcast.jdbc.dataSource.MyDataSource;

public final class JdbcUtils {

    private static MyDataSource myDataSource = null;

    private JdbcUtils() {
    }

    static {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            myDataSource = new MyDataSource();
        } catch (Exception e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    public static Connection getConnection() throws SQLException {
        // return DriverManager.getConnection(url, user, password); //原工具类：创建连接
        return myDataSource.getConnection(); // 取连接
    }

    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 {
                try {
                    if (conn != null)
                        // conn.close(); //原工具类：关闭连接
                        myDataSource.free(conn); // 释放连接
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }
}