孙老师版本JDBC（2022年6月12日21:34:25）

package com.item.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
public class JDBCUtil implements AutoCloseable {
  private static String driver="com.mysql.jdbc.Driver";
  private static String url="jdbc:mysql://127.0.0.1:3306/mytest?characterEncoding=utf-8";
  // 连接对象
  private static Connection conn;
  // 结果集
  private static ResultSet rs;
  // 代码块
  static{
  try {
    Class.forName(driver);
    conn = DriverManager.getConnection(url, "root", "12345678");
  } catch (Exception e) {
    e.printStackTrace();
  }
  }
  /**
  * 全SQL查询
  * @param sql
  * @return
  * @throws SQLException
  */
  public static ResultSet query(String sql) throws SQLException {
  return conn.createStatement().executeQuery(sql);
  }
  /**
  * @param sql
  * @return
  * @throws SQLException
  */
  public static int update(String sql) throws SQLException {
  return conn.prepareStatement(sql).executeUpdate();
  }
  @Override
  public void close() throws Exception {
  if (null != rs) {
    rs.close();
  }
  if (null != conn) {
    conn.close();
  }
  }
}

public static void main(String[] args) throws SQLException {
  ResultSet re = query("select * from users");
  while (re.next()) {
    System.out.println(re.getObject(1));
    System.out.println(re.getObject(2));
    System.out.println(re.getObject(3));
    System.out.println(re.getObject(4));
    System.out.println(re.getObject(5));
  }
  }

/**
  * 转换为Vectors集合
  * 
  * @param userList
  * @return
  */
  public static Vector<Vector<String>> listToVectors(List<UserVo> userList) {
  Vector<Vector<String>> datas = new Vector<Vector<String>>();
  for (int i = 0; i < userList.size(); i++) {
    UserVo u = userList.get(i);
    if (null == u)
    continue;
    Vector<String> item = new Vector<String>();
    item.add(u.getId().toString());
    item.add(u.getAccount());
    item.add(u.getSex() == 1 ? "男" : "女");
    item.add(u.getEducation());
    item.add(u.getPhone());
    item.add(u.getEmail());
    item.add(u.getRegisterDate());
    if (null == u.getUpdateDate()) {
    item.add("");
    }else {
    item.add(u.getUpdateDate());
    }
    datas.add(item);
  }
  return datas;
  }

datas.clear();
datas.addAll(ListDbUtils.listToVectors(userService.list()));
jTable.updateUI();
JTable jTable = new JTable(datas, heads);