hibernate学习之一——Jdbc回顾

package com.util;/* * 问题： * 1、代码量大，比较繁琐 * 2、表数据转换为对象时，很难提取共用 * 3、不同的数据库支持不相同 * 4、对事务处理比较麻烦 */import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import com.bean.User;public class JdbcUtil {public static void main(String[] args) {PreparedStatement st = null;Connection conn = null;ResultSet rs = null;try {// 1.加载驱动Class.forName("com.mysql.jdbc.Driver");// 2,创建连接conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");// 3,创建Statement对象String sql = "select * from user";st = conn.prepareStatement(sql);// 4,执行executers = st.executeQuery();// 5，处理结果集while (rs.next()) {User user = new User();user.setUid(rs.getInt("uid"));user.setName(rs.getString("name"));user.setAge(rs.getInt("age"));System.out.println(user.toString());}} catch (SQLException e) {System.out.println("数据库连接异常！");e.printStackTrace();} catch (ClassNotFoundException e) {System.out.println("驱动加载失败！");e.printStackTrace();} finally {try {// 关闭资源if (rs != null)rs.close();if (st != null)st.close();if (conn != null)conn.close();} catch (SQLException e) {e.printStackTrace();}}}}

package com.bean;public class User {public String toString() {return "User [uid=" + uid + ", name=" + name + ", age=" + age + "]";}private int uid;private String name;private int age;public User() {super();}public User(int uid, String name, int age) {super();this.uid = uid;this.name = name;this.age = age;}public int getUid() {return uid;}public void setUid(int uid) {this.uid = uid;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}