數據庫連接工具將結果集封裝成map或List<Map>

最近做java項目的時候對公司項目的mysql查詢框架得到的結果不滿意，於是自己就整理了部分資料將數據庫查詢的結果封裝成map或者list。希望對大家和自己有一點幫助

1.獲取connection工具類

public final class DBUtil {

    private final static String driverName = "com.mysql.jdbc.Driver";    //驅動
    private final static String url = "jdbc:mysql://localhost:3306/testtwo";
    private final static String userName = "root";
    private final static String pwd = "123456";


    public static Connection getMysqlConnection()
    {
        Connection connection = null;
        try{
            Class.forName(driverName);
            connection = DriverManager.getConnection(url,userName,pwd);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        return connection;
    }
}

2、廢話不多說獲取封裝結果集的精華代碼

public class BaseDao {

    /**
     * 獲取list結果集
     * @param sql
     * @return
     */
    public static List<Map<String, Object>> findListBySql(String sql) {
        List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
        Connection connection = null;
        Statement st = null;
        ResultSet rs = null;
        try
        {
            connection = DBUtil.getMysqlConnection();
            st = connection.createStatement();
            rs = st.executeQuery(sql);
            ResultSetMetaData md = rs.getMetaData();
            int columnCount = md.getColumnCount();
            while (rs.next()) {
                Map<String, Object> rowData = new HashMap<String, Object>();
                for (int i = 1; i <= columnCount; i++) {
                    rowData.put(md.getColumnName(i), rs.getObject(i));
                }
                list.add(rowData);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeResources(rs,st,connection);
        }
        return list;
    }


    /**
     * 獲取map結果集
     * @param sql
     * @return
     */
    public static Map<String, Object> findMapBySql(String sql) {
        Map<String, Object> map = new HashMap<>();
        Connection connection = null;
        Statement st = null;
        ResultSet rs = null;
        try {
            connection = DBUtil.getMysqlConnection();
            st = connection.createStatement();
            rs = st.executeQuery(sql);
            ResultSetMetaData md = rs.getMetaData();
            int columnCount = md.getColumnCount();
            while (rs.next()) {
                for (int i = 1; i <= columnCount; i++) {
                    map.put(md.getColumnName(i), rs.getObject(i));
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeResources(rs,st,connection);
        }
        return map;
    }

    public static void closeResources(ResultSet rs,Statement st,Connection connection)
    {
        try
        {
            if (rs != null)
            {
                rs.close();
            }
            if (st != null)
            {
                st.close();
            }
            if (connection != null)
            {
                connection.close();
            }
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
    }


    public static void main(String[] args) {
       List<Map<String,Object>> list = BaseDao.findListBySql("select * from user   ");
        System.out.println(list.get(0).get("name"));
    }
}