初识JDBC

package com.zq0912;
import utlity.JDBCUtil;

import java.sql.*;

public class maintest {
public static void main(String[] args) throws SQLException {
Connection connection = null;
Statement st = null;
ResultSet rs = null;

    try {   //ctrl+windows+alt+t 跑一层  ctrl+t查看继承结构
        //1.注册驱动
        //静态代码块,类加载了,就执行.
        // Driver中有:DriverManager.registerDriver(new Driver());
        //通过这个方法能把类的字节码加入JVM中

// Class.forName(“com.mysql.jdbc.Driver”); //forname中放类的全路径地址 抓异常,万一找不到类
// DriverManager.registerDriver(new com.mysql.jdbc.Driver());

        connection = JDBCUtil.getConn();
        //2.建立连接,IDEA怎么没有提示信息

// DriverManager.getConnection(“jdbc:mysql://localhost/comzq0914.JAVA_DAO.test?” +
// “user=monty&password=greatsqldb”);
//ctrl+F12查看类的方法
// connection = DriverManager.getConnection(“driverClass”, “root”, “root”);
//协议 子协议 访问本地主机 数据库

        //3.创建statement,跟数据库打交道,一定需要这个对象
        st = connection.createStatement();

        //4.执行查询,得到结果集
        String sql = "select * from t_stu";
        rs = st.executeQuery(sql);

// //5.遍历结果集查询每一条记录
while (rs.next()) {
int id = rs.getInt(“id”);
String name = rs.getString(“name”);
int age = rs.getInt(“age”);
System.out.println(“id” + id + “==name” + name + “==age” + age);
}

        } catch (Exception throwables) {
            throwables.printStackTrace();
        } finally {
            //6.释放资源
            JDBCUtil.release(connection, st, rs);
        }
}

}