jdbc通过properties文件获取连接

在resource文件下创建db.properties文件内容为

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/jdbc?serverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=true
username=root
password=1234

创建基础类BaseDao.java引入properties文件内容

package com.peng.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 is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
    try {
        properties.load(is);
    } catch (IOException e) {
        e.printStackTrace();
    }
    driver=properties.getProperty("driver");
    url=properties.getProperty("url");
    username=properties.getProperty("username");
    password=properties.getProperty("password");
}
public static Connection GetConnection() throws Exception {
    Connection connection=null;
    Class.forName(driver);
    connection = DriverManager.getConnection(url, username, password);
    return connection;
}
//查询公共方法
public static ResultSet execute(Connection connection, PreparedStatement preparedStatement,ResultSet resultSet,String sql,Object[] params) throws SQLException {
  preparedStatement = connection.prepareStatement(sql);
    for (int i = 0; i < params.length; i++) {
        //setObject占位符从1开始，但是Object[]数组从0开始

        preparedStatement.setObject(i+1,params[i]);
    }
     resultSet = preparedStatement.executeQuery();

    return  resultSet;
}
//增删改公共方法
public static int execute(Connection connection,String sql,PreparedStatement preparedStatement,Object[] params) throws SQLException {
   preparedStatement = connection.prepareStatement(sql);
    for (int i = 0; i < params.length; i++) {
        //setObject占位符从1开始，但是Object[]数组从0开始
         preparedStatement.setObject(i+1,params[i]);
    }
    int update = preparedStatement.executeUpdate(sql);
    return update;
}
//释放资源
public static boolean close(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet)  {
    boolean flog=true;
    if(resultSet!=null){
        try {
            resultSet.close();
            resultSet=null;
        } catch (SQLException e) {
            e.printStackTrace();
            flog=false;
        }}
        if(preparedStatement!=null){
        try {
            preparedStatement.close();
            preparedStatement=null;
        } catch (SQLException e) {
            e.printStackTrace();
            flog=false;
        }}
        if(connection!=null){
        try {
            connection.close();
            connection=null;
        } catch (SQLException e) {
            e.printStackTrace();
            flog=false;
        }
    }
        return flog;
}
}