jdbc

package com.demo.advisor.common.entity;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ResourceBundle;

public class JDBC {
    public static void main(String[] args) {

        // 使用资源绑定器绑定属性配置文件
        ResourceBundle bundle = ResourceBundle.getBundle("jdbc");
        String driver = bundle.getString("driver");
        String url = bundle.getString("url");
        String user = bundle.getString("user");
        String password = bundle.getString("password");

        Statement statement = null;
        Connection conn = null;
        try {
            // 1、注册驱动
            /*driver = new com.mysql.cj.jdbc.Driver();
            DriverManager.registerDriver(driver);*/
            Class.forName(driver);
            // 2、获取连接
            conn = DriverManager.getConnection(url, user, password);
            System.out.println("数据库连接对象 = " + conn);
            // 3、获取数据库操作对象
            statement = conn.createStatement();
            // 4、执行sql
            String sql = "insert into user(username,age,profession,sex) values('王六',21,'学生','男')";
            // 专门执行DML语句的(insert delete update)
            // 返回值是“影响数据库中的记录条数”
            int count = statement.executeUpdate(sql);
            System.out.println(count == 1 ? "保存成功" : "保存失败");
            // 5、处理查询结果集
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            // 6、释放资源
            // 为了保证资源一定释放，在finally语句块中关闭资源
            // 并且要遵循从小到大依次关闭
            // 分别对其try..catch
            if (statement != null) {
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }

    }
}

package com.demo.advisor.common.entity;

import java.sql.*;
import java.util.ResourceBundle;

public class JDBC2 {
    public static void main(String[] args) {

        // 使用资源绑定器绑定属性配置文件
        ResourceBundle bundle = ResourceBundle.getBundle("jdbc");
        String driver = bundle.getString("driver");
        String url = bundle.getString("url");
        String user = bundle.getString("user");
        String password = bundle.getString("password");

        Statement statement = null;
        Connection conn = null;
        ResultSet rs = null;
        try {
            // 1、注册驱动
            /*driver = new com.mysql.cj.jdbc.Driver();
            DriverManager.registerDriver(driver);*/
            Class.forName(driver);
            // 2、获取连接
            conn = DriverManager.getConnection(url, user, password);
            // System.out.println("数据库连接对象 = " + conn);
            // 3、获取数据库操作对象
            statement = conn.createStatement();
            // 4、执行sql
            String sql = "select username from user";
            // 专门执行DML语句的(insert delete update)
            // 返回值是“影响数据库中的记录条数”
            rs = statement.executeQuery(sql);
            // 5、处理查询结果集
            while (rs.next()) {
                System.out.println(rs.getString("username"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            // 6、释放资源
            // 为了保证资源一定释放，在finally语句块中关闭资源
            // 并且要遵循从小到大依次关闭
            // 分别对其try..catch
            if (statement != null) {
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }

    }
}

jdbc.properties

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/sms
user=root
password=123456