import java.sql.*;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import com.mysql.jdbc.Connection;

import com.mysql.jdbc.Statement;

public class ConnectMySQL {

    public static String driver = "com.mysql.jdbc.Driver";

    private static String host;

    private static String user;

    private static String pwd;

    private static Connection conn = null;

    private static Statement stmt = null;

    public static void connect(String host, String user, String pwd) {

        ConnectMySQL.close();

        ConnectMySQL.host = host;

        ConnectMySQL.user = user;

        ConnectMySQL.pwd = pwd;

    }

    public static synchronized List<HashMap<String, String>> query(String sql) {

        return ConnectMySQL.result(sql);

    }

    public static synchronized void close() {

        try {

            if (stmt != null) {

                stmt.close();

                stmt = null;

            }

            if (conn != null) {

                conn.close();

                conn = null;

            }

        } catch (SQLException e) {

            e.printStackTrace();

        }

    }

     private static void connectMySQL() {

        try {

            Class.forName(driver).newInstance();

            conn = (Connection) DriverManager.getConnection("jdbc:mysql://"

                    + host + "?useUnicode=true&characterEncoding=UTF8", user,

                    pwd);

        } catch (InstantiationException e) {

            e.printStackTrace();

        } catch (IllegalAccessException e) {

            e.printStackTrace();

        } catch (ClassNotFoundException e) {

            e.printStackTrace();

        } catch (SQLException e) {

            e.printStackTrace();

        }

    }

    private static void statement() {

        if (conn == null) {

            ConnectMySQL.connectMySQL();

        }

        try {

            stmt = (Statement) conn.createStatement();

        } catch (SQLException e) {

            e.printStackTrace();

        }

    }

    private static ResultSet resultSet(String sql) {

        ResultSet rs = null;

        if (stmt == null) {

            ConnectMySQL.statement();

        }

        try {

            rs = stmt.executeQuery(sql);

        } catch (SQLException e) {

            e.printStackTrace();

        }

        return rs;

    }

    private static List<HashMap<String, String>> result(String sql) {

        ResultSet rs = ConnectMySQL.resultSet(sql);

        List<HashMap<String, String>> result = new ArrayList<HashMap<String, String>>();

        try {

            ResultSetMetaData md = rs.getMetaData();

            int cc = md.getColumnCount();

            while (rs.next()) {

                HashMap<String, String> columnMap = new HashMap<String, String>();

                for (int i = 1; i <= cc; i++) {

                    columnMap.put(md.getColumnName(i), rs.getString(i));

                }

                result.add(columnMap);

            }

        } catch (SQLException e) {

            e.printStackTrace();

        }

        return result;

    }

    public static void main(String[] args) throws SQLException {

        ConnectMySQL

                .connect("192.168.1.1/test", "test", "test");

        List<HashMap<String, String>> rs = ConnectMySQL

                .query("SELECT * from test");

        System.out.println(rs.get(0).get("test"));

        ConnectMySQL.close();

}

}