《Java高级编程应用》实验七八 数据库编程1.docx

1、Java高级编程应用实验七八 数据库编程1实验七、八 数据库编程一、实验目的1、掌握数据库连接用到的主要API；2、掌握数据库连接两种常用的方法。二、实验内容1、请以数据查询为例，简述连接数据库的步骤。1.注册数据库的驱动2.通过DriverManager获取数据库连接3.通过Connection对象获取Statement4.使用Statement执行SQL语句5.操作ResultSet结果集6.回收据库资源2、借助JDBC方式连接数据库，查询某班学生的花名册（含学号、姓名）。源程序：package JDBC;import java.sql.Connection;import java.sql

2、.DriverManager;import java.sql.ResultSet;import java.sql.Statement;public class Database_Connectivity public static void main(String args) Statement stmt = null; ResultSet rs = null; Connection conn = null; try /1.注册数据库的驱动 Class.forName(com.mysql.jdbc.Driver); /2.通过DriverManager获取数据库连接 String url =

3、jdbc:mysql:/localhost:3306/gradem; String username = root; String password = 123; conn = DriverManager.getConnection(url,username,password); /3.通过Connection对象获取Statement stmt = conn.createStatement(); /4.使用Statement执行SQL语句 String sql = select * from student; rs = stmt.executeQuery(sql); /5.操作ResultS

4、et结果集 System.out.println(t学号+t|t+姓名); while (rs.next() String sno = rs.getString(sno); String sname = rs.getString(sname); System.out.println( +sno+t|t+sname); catch(Exception e) e.printStackTrace(); finally /6.回收据库资源 if (rs != null) try rs.close(); catch(Exception e) e.printStackTrace(); rs = null;

5、 if (stmt != null) try stmt.close(); catch(Exception e) e.printStackTrace(); stmt = null; if (conn != null) try conn.close(); catch(Exception e) e.printStackTrace(); conn = null; 3、完善用户的登录程序，实现从数据库访问用户名和密码的登录控制。源程序： package JDBC;import java.sql.*;public class LoginVerify private static int b; public

6、 static void main(String args) String login_name = KDs; String login_password = 1234; Statement stmt = null; ResultSet rs = null; Connection conn = null; b=1; try /1.注册数据库的驱动 Class.forName(com.mysql.jdbc.Driver); /2.通过DriverManager获取数据库连接 String url = jdbc:mysql:/localhost:3306/gradem; String userna

7、me = root; String password = 123; conn = DriverManager.getConnection(url,username,password); /3.通过Connection对象获取Statement stmt = conn.createStatement(); /4.使用Statement执行SQL语句 String sql = select * from Users; rs = stmt.executeQuery(sql); /5.操作ResultSet结果集 while (rs.next() String user_name = rs.getSt

8、ring(user_name); String user_password = rs.getString(user_password); if(login_name.equals(user_name) b = 1; if (login_password.equals(user_password) System.out.println(登录成功！); else System.out.println(密码错误！登录失败！); else b = 0; if(b = 0) System.out.println(该用户名未注册！登录失败！); catch(Exception e) e.printStac

9、kTrace(); 4、在题目3的基础上完善用户的登录程序，实现如下用户的登录控制。源程序：package JDBC;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.MouseEvent;import java.awt.event.MouseListener;import java.sql.Connection;import java.sql.DriverManager;import java.sql.R

10、esultSet;import java.sql.Statement;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JOptionPane;import javax.swing.JPanel;import javax.swing.JPasswordField;import javax.swing.JTextField;import java.awt.BorderLayout;import java.awt.Color;import java.aw

11、t.Font;import java.awt.Graphics;import java.util.Random;public class LoginIntact JTextField tf,tf_security_code; JPasswordField pf; JFrame f; JLabel lName,lPassword,refresh_security_code; JButton bLogin,bQuit; JPanel p1,p2,p3,p4; private static int b; public LoginIntact() / TODO Auto-generated const

12、ructor stub f = new JFrame(); tf=new JTextField(18); tf_security_code = new JTextField(10);/验证码输入框 pf=new JPasswordField(18); lName=new JLabel(用户名：); lPassword=new JLabel(密 码：); bLogin=new JButton(登录); bQuit=new JButton(取消); refresh_security_code = new JLabel(看不清，换一张); /-登录取消添加事件监听 bLogin.addActionL

13、istener(new ActionListener() public void actionPerformed(ActionEvent e) String login_name = tf.getText(); String login_password = pf.getText(); Statement stmt = null; ResultSet rs = null; Connection conn = null; b=1; try /1.注册数据库的驱动 Class.forName(com.mysql.jdbc.Driver); /2.通过DriverManager获取数据库连接 Str

14、ing url = jdbc:mysql:/localhost:3306/gradem; String username = root; String password = 123; conn = DriverManager.getConnection(url,username,password); /3.通过Connection对象获取Statement stmt = conn.createStatement(); /4.使用Statement执行SQL语句 String sql = select * from Users; rs = stmt.executeQuery(sql); /5.操

15、作ResultSet结果集 String input_code = tf_security_code.getText();/获取用户输入的验证码 String ss = new myJPanel().sb.toString(); System.out.println(ss); if(ss.equalsIgnoreCase(input_code) new myJPanel().repaint();/重绘验证码面板 if(.equals(tf.getText() | .equals(pf.getText() JOptionPane.showMessageDialog(null,用户名或密码为空！登

16、录失败！); else while (rs.next() String user_name = rs.getString(user_name); String user_password = rs.getString(user_password); if(login_name.equals(user_name) b = 1; if (login_password.equals(user_password) JOptionPane.showMessageDialog(null,登陆成功！); / System.out.println(登录成功！); tf.setText(); pf.setTex

17、t(); tf_security_code.setText();/刷新验证码时，清空验证码输入框 else / System.out.println(密码错误！登录失败！); JOptionPane.showMessageDialog(null,密码错误，登录失败); else b = 0; if(b = 0) / System.out.println(该用户名未注册！登录失败！); JOptionPane.showMessageDialog(null,用该用户名未注册！登录失败！); else JOptionPane.showMessageDialog(null,验证码输入错误！请重新输入！

18、); catch(Exception ee) ee.printStackTrace(); ); bQuit.addActionListener(new ActionListener() public void actionPerformed(ActionEvent e) System.exit(0); ); refresh_security_code.addMouseListener(new MouseListener() Override public void mouseClicked(MouseEvent arg0) / TODO Auto-generated method stub f

19、.setVisible(true); f.repaint();/重绘刷新 tf_security_code.setText();/刷新验证码时，清空验证码输入框 Override public void mouseEntered(MouseEvent e) / TODO Auto-generated method stub Override public void mouseExited(MouseEvent e) / TODO Auto-generated method stub Override public void mousePressed(MouseEvent e) / TODO A

20、uto-generated method stub Override public void mouseReleased(MouseEvent e) / TODO Auto-generated method stub ); /- p1 = new JPanel(); p2 = new JPanel(); p3 = new JPanel(); p4 = new JPanel(); JPanel pp = new JPanel(); p1.add(lName); p1.add(tf); p2.add(lPassword); p2.add(pf); p3.add(new myJPanel(); pp

21、.add(tf_security_code); p3.add(pp); p3.add(refresh_security_code); p4.add(bLogin); p4.add(bQuit); /-添加部件 f.add(new JPanel(); f.add(p1); f.add(p2); f.add(p3); f.add(p4); /-布局设置 f.setLayout(new GridLayout(5,1); p3.setLayout(new GridLayout(1,3); /-窗体设置 f.setVisible(true); f.setBounds(200,300,400,300);

22、static class myJPanel extends JPanel public static StringBuilder sb; public void paint(Graphics g) int width = 130; int height = 35; g.setColor(Color.LIGHT_GRAY);/设置上下文颜色 g.fillRect(0, 0, width, height);/填充验证码背景 g.setColor(Color.black);/设置上下文颜色 g.drawRect(0, 0, width - 1, height - 1);/绘制边框 /绘制干扰点 Ra

23、ndom r = new Random(); for (int i = 0; i 100; i+) int x = r.nextInt(width) - 2; int y = r.nextInt(height) -2; g.drawOval(x, y, 2, 2); g.setFont(new Font(黑体, Font.BOLD, 30);/设置验证码字体 g.setColor(Color.BLUE);/设置验证码颜色 /产生随机验证码 char chars = (abcdefghigklmnopqistuvwxyzABCDEFGHIJKLMNOPQISTUVWXYZ +0123456789).toCharArray(); sb = new StringBuilder(); for (int i = 0; i 4; i+) int pos = r.nextInt(chars.length); char c = charspos; sb.append(c+); g.drawString(sb.toString(), 20, 30);/写入验证码 public static void main(String args) new LoginIntact(); 三、实验总结