简单的数据库连接代码示范！！

import java.sql.Connection; //import java.sql.Date; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.Date; import java.util.Scanner; public class TestLogin { public static void main(String[] args) { // TODO Auto-generated method stub System.out.println("请输入用户名"); String username = new Scanner(System.in).next(); System.out.println("请输入密码"); String password = new Scanner(System.in).next(); UserBean user = null; try { Class.forName("com.mysql.jdbc.Driver"); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } Connection con = null; try { con =DriverManager.getConnection("jdbc:mysql://localhost:3306/dms?userUnicode=true&charaterEncoding=uft-8&useSSL=false", "root", "12345"); con.setAutoCommit(false);//设置自动提交为假，开启事务 // String sql = "select t_admin,t_passWord from t_manage where t_admin=? and t_passWord=?"; // //PreparedStatement stat = con.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS); // PreparedStatement stat = con.prepareStatement(sql); // stat.setString(1, username); // stat.setString(2, password); // ResultSet b = stat.executeQuery(); // //ResultSet a = stat.getGeneratedKeys();//增加操作的时候用 String sql2 ="update t_manage set t_admin = ?,t_passWord = ?where t_admin = ? "; PreparedStatement ps2 = con.prepareStatement(sql2); ps2.setString(1, username); ps2.setString(2, password); ps2.setString(3, username); // Date birth = new Date(); // ps2.setDate(4,new java.sql.Date(birth.getTime())); int b = ps2.executeUpdate(); // while(a.next()){ // String userName = a.getString("t_admin"); // String passWord = a.getString("t_passWord"); // user = new UserBean(userName,passWord); // } System.out.println(b); con.commit();//手动提交---之前所有操作都正常，在最后整体提交 } catch (SQLException e) { // TODO Auto-generated catch block try { con.rollback();//回滚 } catch (SQLException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } e.printStackTrace(); } if (user != null) { System.out.println("登陆成功"); } else { System.out.println("登陆失败"); } } }