java数据库读取数据库 javaweb读取数据库表内容

package com.wang.dao;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

public class BaseDao {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;

    static {
        Properties properties = new Properties();
        InputStream io = BaseDao.class.getClassLoader().getResourceAsStream("jdbc.properties");

        try {
            properties.load(io);
        } catch (IOException e) {
            e.printStackTrace();
        }
        driver=properties.getProperty("jdbc.driver");
        url=properties.getProperty("jdbc.url");
        username=properties.getProperty("jdbc.user");
        password=properties.getProperty("jdbc.password");

    }

    public static Connection getConnection(){
        Connection connection=null;
        try {
            Class.forName(driver);
            connection= DriverManager.getConnection(url, username, password);
        } catch (Exception e) {
            e.printStackTrace();
        }


        return connection;
    }

    public static ResultSet execute(Connection connection,PreparedStatement pstm,ResultSet resultSet,String sql,Object[] params) throws SQLException {
        pstm = connection.prepareStatement(sql);
        for (int i = 0; i <params.length ; i++) {
            pstm.setObject(i+1,params[i]);

        }
        resultSet = pstm.executeQuery();
        return resultSet;


    }


    public static int execute(Connection connection,PreparedStatement pstm,String sql,Object[] params) throws SQLException {
        pstm = connection.prepareStatement(sql);
        for (int i = 0; i <params.length ; i++) {
            pstm.setObject(i+1,params[i]);

        }
        int update = pstm.executeUpdate();
        return update;


    }

    public static boolean closeResource(Connection connection,PreparedStatement pstm,ResultSet resultSet)
    {
        boolean flag=true;


        if (connection!=null)
        {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
                flag=false;
            }

        }
        if (pstm!=null)
        {
            try {
                pstm.close();
            } catch (SQLException e) {
                e.printStackTrace();
                flag=false;
            }

        }
        if (resultSet!=null)
        {
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
                flag=false;
            }

        }
        return flag;
    }






}