jdbc工具类

定义配置文件放在src目录下

#数据库连接路径
url=jdbc:mysql://localhost/day16
#登录用户名
username=root
#登录密码
password=root
#注册驱动
driver=com.mysql.jdbc.Driver

数据库连接工具类

package cn.itcast.utils;

import java.io.FileInputStream;
import java.io.IOException;
import java.net.URL;
import java.sql.*;
import java.util.Properties;

public class JDBCUtils {
    private static String url;
    private static String users;
    private static String password;
    private static String driver;

    
    static{
        //读取资源文件获取值
        Properties pro = new Properties();
        try {
            //获取src路径下文件的方式-->ClassLoader
            ClassLoader cl = JDBCUtils.class.getClassLoader();
            URL res = cl.getResource("jdbc.properties");
            String path = res.getPath();
            pro.load(new FileInputStream(path));
            url = pro.getProperty("url");
            users = pro.getProperty("users");
            password = pro.getProperty("password");
            driver = pro.getProperty("driver");

//            注册驱动
            Class.forName(driver);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }


    }
    


    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url,users,password);
    }


    
    public static void close(Statement stmt,Connection conn){
        if(stmt != null){
            try {
                stmt.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }

    public static void close(Statement stmt, Connection conn, ResultSet rs){
        if(stmt != null){
            try {
                stmt.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(rs !=null ){
            try {
                rs.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }
}