一、题目
编写一个应用程序，输入用户名和密码，访问test数据库中t_login表（字段包括id、username、password），验证登录是否成功。
二、源代码
package TwentuSixth; /* * 通过JDBC直连和加载驱动建立连接，两个textfiled分别接受username和password通过sql语句查询并输出结果 * * */ import java.awt.BorderLayout; import java.awt.EventQueue; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.border.EmptyBorder; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JTextField; import javax.swing.JButton; import java.awt.event.ActionListener; import java.awt.event.ActionEvent; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class Test extends JFrame { private JPanel contentPane; private JTextField textField; private JTextField textField_1; Connection con = null; /** * Launch the application. */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { Test frame = new Test(); frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } /** * Create the frame. */ public Test() { setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setBounds(100, 100, 450, 300); contentPane = new JPanel(); contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); setContentPane(contentPane); contentPane.setLayout(null); JLabel label = new JLabel("\u7528\u6237\u540D\uFF1A"); label.setBounds(66, 72, 54, 15); contentPane.add(label); JLabel label_1 = new JLabel("\u5BC6\u7801\uFF1A"); label_1.setBounds(66, 134, 54, 15); contentPane.add(label_1); textField = new JTextField(); textField.setBounds(173, 69, 164, 21); contentPane.add(textField); textField.setColumns(10); textField_1 = new JTextField(); textField_1.setBounds(173, 134, 164, 21); contentPane.add(textField_1); textField_1.setColumns(10); JButton button = new JButton("\u767B\u5F55"); button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { try { Class.forName("com.mysql.jdbc.Driver"); Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","0000"); Statement st = con.createStatement(); ResultSet rs = st.executeQuery("select * from t_login where username = '"+textField.getText()+"' and password = '"+textField_1.getText()+"'"); if(rs.next()){ JOptionPane.showMessageDialog(null, "登陆成功！"); }else{ JOptionPane.showMessageDialog(null, "登陆失败。"); } if(rs!=null){ rs.close(); } st.close(); con.close(); } catch (SQLException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } } }); button.setBounds(147, 200, 93, 23); contentPane.add(button); } }
三、运行结果
一、题目
在上一题基础上，当登录成功后，将t_user表（id、name、sex、birthday）的信息进行显示（要求使用DB.java完成登录和获取t_user表中数据的操作），最后再对t_user表进行一条记录的添加操作。
二、源代码
1.DB.java
package TewntySeventh; /* * DB类，存放加载驱动，直连方式和各种方法 * * */ import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class DB { private Connection con; private PreparedStatement pre; private ResultSet rs; private static DB db; static { try { Class.forName("com.mysql.jdbc.Driver"); } catch (ClassNotFoundException e) { e.printStackTrace(); } } DB() { try { con = DriverManager.getConnection( "jdbc:mysql://localhost:3306/test", "root", "0000"); } catch (SQLException e) { e.printStackTrace(); } } public static DB getInstance() { if (db == null) { db = new DB(); } return db; } public ResultSet executeSelect(String sql, Object[] args) { try { pre = con.prepareStatement(sql); if (args.length != 0) { for (int i = 0; i < args.length; i++) { pre.setObject(i + 1, args[i]); } } rs = pre.executeQuery(); } catch (SQLException e) { e.printStackTrace(); } return rs; } public int executeModify(String sql, Object[] args) { int n = 0; try { pre = con.prepareStatement(sql); if (args.length != 0) { for (int i = 0; i < args.length; i++) { pre.setObject(i + 1, args[i]); } } n = pre.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return n; } public void close() { try { if (rs != null) { rs.close(); } pre.close(); con.close(); } catch (SQLException e) { e.printStackTrace(); } } }
2.Login.java
package TewntySeventh; /* * 和上面的一样，通过JDBC直连并判断结果然后输出 * * */ import java.awt.BorderLayout; import java.awt.EventQueue; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.border.EmptyBorder; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JTextField; import javax.swing.JButton; import java.awt.event.ActionListener; import java.awt.event.ActionEvent; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class Login extends JFrame { private JPanel contentPane; private JTextField textField; private JTextField textField_1; Connection con = null; /** * Launch the application. */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { Login frame = new Login(); frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } /** * Create the frame. */ public Login() { setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setBounds(100, 100, 450, 300); contentPane = new JPanel(); contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); setContentPane(contentPane); contentPane.setLayout(null); JLabel label = new JLabel("\u7528\u6237\u540D\uFF1A"); label.setBounds(66, 72, 54, 15); contentPane.add(label); JLabel label_1 = new JLabel("\u5BC6\u7801\uFF1A"); label_1.setBounds(66, 134, 54, 15); contentPane.add(label_1); textField = new JTextField(); textField.setBounds(173, 69, 164, 21); contentPane.add(textField); textField.setColumns(10); textField_1 = new JTextField(); textField_1.setBounds(173, 134, 164, 21); contentPane.add(textField_1); textField_1.setColumns(10); JButton button = new JButton("\u767B\u5F55"); button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { try { Class.forName("com.mysql.jdbc.Driver"); Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","0000"); Statement st = con.createStatement(); ResultSet rs = st.executeQuery("select * from t_login where username = '"+textField.getText()+"' and password = '"+textField_1.getText()+"'"); if(rs.next()){ JOptionPane.showMessageDialog(null, "登陆成功！"); Select Select=new Select(); Select.setVisible(true); setVisible(false); }else{ JOptionPane.showMessageDialog(null, "登陆失败。"); } if(rs!=null){ rs.close(); } st.close(); con.close(); } catch (SQLException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } } }); button.setBounds(147, 200, 93, 23); contentPane.add(button); } }
3.Select.java
package TewntySeventh; /* * 加载DB里面的executeSelect方法获取查询结果，然后通过Jtable将其显示 * */ import java.awt.BorderLayout; import java.awt.EventQueue; import javax.swing.Box; import javax.swing.BoxLayout; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTable; import javax.swing.border.EmptyBorder; import javax.swing.table.DefaultTableModel; import javax.swing.JScrollPane; import javax.swing.border.LineBorder; import java.awt.Color; import javax.swing.border.TitledBorder; import javax.swing.UIManager; import javax.swing.JButton; import java.awt.event.ActionListener; import java.awt.event.ActionEvent; import java.sql.ResultSet; public class Select extends JFrame { private JPanel contentPane; private JTable table; private String str[]={"id","name","sex","birthday"}; private JButton button_1; /** * Launch the application. */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { Select frame = new Select(); frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } /** * Create the frame. */ public Select() { setTitle("\u5217\u8868\u663E\u793A\u5143\u7D20"); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setBounds(100, 100, 450, 500); contentPane = new JPanel(); contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); setContentPane(contentPane); contentPane.setLayout(null); JScrollPane scrollPane = new JScrollPane(); scrollPane.setBounds(10, 20, 414, 387); contentPane.add(scrollPane); table = new JTable(); table.setModel(new DefaultTableModel( new Object[][] { {null,null,null,null}, }, new String[] { "id", "name", "sex", "birthday" } )); scrollPane.setViewportView(table); JButton button = new JButton("\u67E5\u8BE2"); button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { DB db=new DB(); ResultSet s=db.executeSelect("select * from t_user",new Object[]{}); try { if(s.last()){ int a=s.getRow(); Object[][] date=new Object[a][]; int b=s.getMetaData().getColumnCount(); s.beforeFirst(); int i=0; while (s.next()) { date[i]=new Object[b]; for (int j = 0; j < b; j++) { date[i][j]=s.getObject(j+1); } i++; } DefaultTableModel m=new DefaultTableModel(date,str); table.setModel(m); } } catch (Exception e) { // TODO: handle exception } table.setVisible(false); table.setVisible(true); } }); button.setBounds(82, 417, 93, 23); contentPane.add(button); button_1 = new JButton("\u6DFB\u52A0"); button_1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { Add add=new Add(); add.setVisible(true); setVisible(false); /*Select Select=new Select(); Select.setVisible(true); setVisible(false);*/ } }); button_1.setBounds(257, 417, 93, 23); contentPane.add(button_1); /* JFrame frame = new JFrame(); String[] columnNames = { "火影", "风影", "雷影", "水影", "土影" }; DefaultTableModel model = new DefaultTableModel(columnNames, 0); JTable jTable = new JTable(model); JScrollPane scrollPane = new JScrollPane(jTable); frame.add(scrollPane); frame.pack(); frame.setVisible(true); frame.setLocationRelativeTo(null); // 获取JTable中的model DefaultTableModel model2 = (DefaultTableModel) jTable.getModel(); String[] column1 = { "初代火影", "初代风影", "初代雷影", "初代水影", "初代土影" }; model.addRow(column1); */ } }
4.Add.java
package TewntySeventh; /* * 获取testfiled的值将其做返回，radiobutton放进group里，然后根据不同的返回值获取相应的值并输出 * * */ import java.awt.BorderLayout; import java.awt.EventQueue; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.border.EmptyBorder; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JRadioButton; import javax.swing.ButtonGroup; import javax.swing.JTextField; import javax.swing.JButton; import java.awt.event.ActionListener; import java.awt.event.ActionEvent; import java.sql.ResultSet; public class Add extends JFrame { private JPanel contentPane; private final ButtonGroup buttonGroup = new ButtonGroup(); private JTextField textField; private JTextField textField_1; /** * Launch the application. */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { Add frame = new Add(); frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } /** * Create the frame. */ public Add() { setTitle("\u6DFB\u52A0\u4FE1\u606F"); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setBounds(100, 100, 450, 300); contentPane = new JPanel(); contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); setContentPane(contentPane); contentPane.setLayout(null); JLabel label = new JLabel("\u7528\u6237\u540D\uFF1A"); label.setBounds(46, 51, 66, 15); contentPane.add(label); JLabel label_1 = new JLabel("\u51FA\u751F\u65E5\u671F\uFF1A"); label_1.setBounds(46, 167, 66, 15); contentPane.add(label_1); JRadioButton rdbtnNewRadioButton = new JRadioButton("\u7537"); rdbtnNewRadioButton.setActionCommand("1"); buttonGroup.add(rdbtnNewRadioButton); rdbtnNewRadioButton.setBounds(132, 109, 45, 23); contentPane.add(rdbtnNewRadioButton); JRadioButton rdbtnNewRadioButton_1 = new JRadioButton("\u5973"); rdbtnNewRadioButton_1.setActionCommand("0"); buttonGroup.add(rdbtnNewRadioButton_1); rdbtnNewRadioButton_1.setBounds(196, 109, 51, 23); contentPane.add(rdbtnNewRadioButton_1); textField = new JTextField(); textField.setBounds(132, 48, 143, 21); contentPane.add(textField); textField.setColumns(10); textField_1 = new JTextField(); textField_1.setBounds(132, 164, 143, 21); contentPane.add(textField_1); textField_1.setColumns(10); JButton button = new JButton("\u63D0\u4EA4"); button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { DB db=new DB(); String buttonGroupText=buttonGroup.getSelection().getActionCommand(); int s=db.executeModify("insert into t_user (name,sex,birthday)values('"+textField.getText()+"','"+buttonGroupText+"','"+textField_1.getText()+"')", new Object[]{}); if(s>0){ JOptionPane.showMessageDialog(null, "添加成功！"); }else{ System.out.print("添加失败\n"); } } }); button.setBounds(84, 211, 93, 23); contentPane.add(button); JLabel label_2 = new JLabel("\u6027\u522B\uFF1A"); label_2.setBounds(46, 113, 45, 15); contentPane.add(label_2); JButton btnNewButton = new JButton("\u8FD4\u56DE\u67E5\u770B\u5217\u8868"); btnNewButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { Select Select=new Select(); Select.setVisible(true); setVisible(false); } }); btnNewButton.setBounds(230, 211, 126, 23); contentPane.add(btnNewButton); } }
三、运行结果
