IRowMapper接口：

package com.jd.ntil.db;

import java.sql.ResultSet;

public interface IReowMapper {
    void mapRow(ResultSet resultSet);
}

PropertiesUtil类：

package com.jd.ntil.db;

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

public class PropertiesUtil {
    static Properties properties = new Properties();

    static {
        InputStream inputStream =PropertiesUtil.class.getClassLoader().getResourceAsStream("db.properties");
        try {
            properties.load(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static String value(String key){
        return properties.getProperty(key);
    }
}

db.properties文件

url=jdbc:mysql://localhost:3306/venususeSSL=false&serverTimezone=UTC
user=root
password=123456

DBUtil类：

package com.jd.ntil.db;
import java.sql.*;
public class
DBUtil {
    static {
        //1加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    public static Connection getconnection() throws SQLException {
        //2.获取数据库连接
        String url = PropertiesUtil.value("url");
        String user=PropertiesUtil.value("user");
        String password=PropertiesUtil.value("password");
            return DriverManager.getConnection(url,user,password);
    }
    public static boolean update(String sql){

            try (//6.释放资源
                 Connection connection = getconnection();
                 Statement statement = connection.createStatement();
            ) {
                //3.创建sql语句

                //4.执行sql语句
                int effect = statement.executeUpdate(sql);
                //5.处理结果
                return effect>0;
            } catch (SQLException throwables) {
            }
            return false;
        }
    public static boolean update(String sql,Object...object){

        try (//6.释放资源
             Connection connection = getconnection();
             PreparedStatement prepareStatement = connection.prepareStatement(sql);
        ) {
            //3.创建sql语句
            for (int i = 0; i < object.length; i++) {
                prepareStatement.setObject(i+1,object[i]);
            }
            //4.执行sql语句
            int effect = prepareStatement.executeUpdate();
            //5.处理结果
            return effect>0;
        } catch (SQLException throwables) {

        }
        return false;

    }
//    public static void select(String sql, IReowMapper IReowMapper){
//        Connection connection =null;
//        Statement statement = null;
//        ResultSet resultSet = null;
//        try {
//            //2.获取数据库连接
//            connection = getconnection();
//            //3.创建语句
//            statement = connection.createStatement();
//            //4.执行sql语句
//            resultSet = statement.executeQuery(sql);
//            IReowMapper.mapRow(resultSet);
//
//        }catch(SQLException throwables){
//            throwables.printStackTrace();
//            //6.释放资源
//        }
//        close(resultSet,connection,statement);
//    }
    public static void select(String sql, IReowMapper IReowMapper){
        try (            //2.获取数据库连接
                         Connection connection = getconnection();
                         //3.创建语句
                         Statement statement = connection.createStatement();
                         //4.执行sql语句
                         ResultSet resultSet = statement.executeQuery(sql);){

            IReowMapper.mapRow(resultSet);

        }catch(SQLException throwables){
            throwables.printStackTrace();
        }
    }
    public static void select(String sql,IReowMapper iReowMapper,Object...objects){
        Connection connection =null;
        PreparedStatement preparedStatement =null;
        ResultSet resultSet=null;
        try {
            connection =getconnection();
            preparedStatement = connection.prepareStatement(sql);
            for (int i = 0; i < objects.length; i++) {
                preparedStatement.setObject(i+1,objects[i]);
            }
            resultSet=preparedStatement.executeQuery();
            iReowMapper.mapRow(resultSet);
            DBUtil.close(resultSet,connection,preparedStatement);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        close(resultSet, connection, preparedStatement);
    }
    public static boolean exist(String sql){
        Connection connection =null;
        Statement statement =null;
        ResultSet resultSet =null;
        try {
            connection = getconnection();
            statement = connection.createStatement();
            resultSet = statement.executeQuery(sql);
            return resultSet.next();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        close(resultSet,connection,statement);
        return false;
    }
    public static boolean exist(String sql,Object...object){
        Connection connection =null;
        PreparedStatement preparedStatement =null;
        ResultSet resultSet =null;
        try {
            connection = getconnection();
            preparedStatement = connection.prepareStatement(sql);
            for (int i = 0; i < object.length; i++) {
                preparedStatement.setObject(i+1,object[i]);
            }
            resultSet = preparedStatement.executeQuery();
            return resultSet.next();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        close(resultSet,connection,preparedStatement);
        return false;
    }
    private static void close(Connection connection,Statement statement){
        if (statement!=null) {
            try {
                statement.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if (connection!=null) {
            try {
                connection.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }
    private static void close(ResultSet resultSet,Connection connection,Statement statement){
        if (resultSet!=null) {
            try {
                resultSet.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if (statement!=null) {
            try {
                statement.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if (connection!=null) {
            try {
                connection.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }
}