（）java jdbc连接

测试使用 jdk-8u191-windows-x64、mysql-8.0.12-winx64、mysql-connector-java-8.0.13.jar

查询

import java.sql.*;

public class Main {

    //JDBC 驱动名
    //static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    //JDBC 连接串
    //static final String DB_URL = "jdbc:mysql://localhost:3306/world";
    static final String DB_URL = "jdbc:mysql://localhost:3306/world?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC";
    // 数据库的用户名与密码
    static final String USER = "root";
    static final String PASS = "Rock3690";

    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        String sql="SELECT * FROM world.city;";
        try {
            // 注册 JDBC 驱动，
            //Class.forName(JDBC_DRIVER);       
            //连接数据库
            conn = DriverManager.getConnection(DB_URL, USER, PASS);
            //声明
            stmt = conn.createStatement();
            //结果集对象存放查询的数据
            ResultSet rs = stmt.executeQuery(sql);
            //
            while(rs.next()){
                // 赋值
                int id  = rs.getInt("id");
                String name = rs.getString("name");
                String population = rs.getString("population");

                // 输出
                System.out.print("ID: " + id);
                System.out.print(", 城市名称: " + name);
                System.out.print(", 城市人口: " + population);
                System.out.print("\n");
            }
            //关闭
            rs.close();
            stmt.close();
            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}