login

package addresslist;

import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;

import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import javax.swing.ImageIcon;
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 javax.swing.border.EmptyBorder;

import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

/*
 * 封装的太差啦！
 * 要好好理解继承封装多态的使用
 * 不然代码就没法看了
 * 其实是后期修改太困难啦
 * 通用模版的使用
 * 代码的可复用性
 * 考虑好了之后再动手敲代码
 * 不然写了维护起来也比较困难最后只好放弃
 *
 * 然后就是代码的重构与优化
 *
 */
public class login extends JFrame {

    private JPanel contentPane;
    private JTextField textField;
    private JPasswordField passwordField;
    public Judge judge=new Judge();
    static String username;
    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    JFrame fra = new login();
                    fra.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public void setall(String n,String p){
        textField.setText(n);
        passwordField.setText(p);
    }

    public login() {
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new NewPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);

        JLabel label = new JLabel("\u7528\u6237\u540D");

        textField = new JTextField();
        textField.setColumns(10);

        JLabel label_1 = new JLabel("*");
        textField.addFocusListener(new FocusAdapter() {
            @Override
            public void focusLost(FocusEvent e) {
                try {
                    String s=textField.getText().toString();
                    if(!judge.exist(s)){
                        label_1.setText("no such nickname!");
                    }
                } catch (Exception e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            }
            @Override
            public void focusGained(FocusEvent e) {
                label_1.setText("*");
            }
        });

        JLabel label_2 = new JLabel("\u5BC6\u7801");

        passwordField = new JPasswordField();

        JButton btnLogin = new JButton("login");
        btnLogin.addKeyListener(new KeyAdapter() {
            @Override
            public void keyPressed(KeyEvent e) {
                if(e.getKeyCode()==10){
                    btnLogin.doClick();
                }
            }
        });

        btnLogin.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String s=new String(passwordField.getPassword());
                String n=textField.getText().toString();
                try {
                    if(judge.canlogin(n,s)){
                        username=n;
                        mainFrame frame=new mainFrame();
                        frame.setVisible(true);
                        dispose();
                    }
                    else{
                        JOptionPane.showMessageDialog(null, "密码或用户名错误");
                    }
                } catch (Exception e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            }
        });

        JButton btnRegister = new JButton("register");
        btnRegister.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                register rs=new register();
                rs.setVisible(true);
            }
        });
        GroupLayout gl_contentPane = new GroupLayout(contentPane);
        gl_contentPane.setHorizontalGroup(
            gl_contentPane.createParallelGroup(Alignment.LEADING)
                .addGroup(gl_contentPane.createSequentialGroup()
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
                        .addGroup(gl_contentPane.createSequentialGroup()
                            .addGap(66)
                            .addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
                                .addComponent(label)
                                .addComponent(label_2))
                            .addGap(18)
                            .addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING, false)
                                .addComponent(passwordField)
                                .addComponent(textField, GroupLayout.DEFAULT_SIZE, 107, Short.MAX_VALUE))
                            .addGap(28)
                            .addComponent(label_1))
                        .addGroup(gl_contentPane.createSequentialGroup()
                            .addGap(80)
                            .addComponent(btnLogin)
                            .addGap(37)
                            .addComponent(btnRegister)))
                    .addContainerGap(151, Short.MAX_VALUE))
        );
        gl_contentPane.setVerticalGroup(
            gl_contentPane.createParallelGroup(Alignment.LEADING)
                .addGroup(gl_contentPane.createSequentialGroup()
                    .addGap(48)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
                        .addComponent(label)
                        .addGroup(gl_contentPane.createParallelGroup(Alignment.TRAILING)
                            .addComponent(label_1)
                            .addComponent(textField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)))
                    .addGap(29)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                        .addComponent(label_2)
                        .addComponent(passwordField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
                    .addGap(48)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                        .addComponent(btnLogin)
                        .addComponent(btnRegister))
                    .addContainerGap(61, Short.MAX_VALUE))
        );
        contentPane.setLayout(gl_contentPane);
    }
 class NewPanel extends JPanel{
    public NewPanel() {}

    public void paintComponent(Graphics g)
    {
       int x=0,y=0;
       java.net.URL imgURL=getClass().getResource("login.jpg");

       //test.jpg是测试图片，与Demo.java放在同一目录下
        ImageIcon icon=new ImageIcon(imgURL);//this is really useful
        g.drawImage(icon.getImage(),x,y,getSize().width,getSize().height,this);
        while(true)
        {
          g.drawImage(icon.getImage(),x,y,this);
          if(x>getSize().width && y>getSize().height)break;
         //这段代码是为了保证在窗口大于图片时，图片仍能覆盖整个窗口
         if(x>getSize().width)
          {
             x=0;
             y+=icon.getIconHeight();
          }
          else
           x+=icon.getIconWidth();
        }
     }
   }
}

package addresslist;

import java.awt.BorderLayout;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.JPasswordField;
import javax.swing.JButton;

import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class register extends JFrame {

    private JPanel contentPane;
    private JTextField textField;
    private JPasswordField passwordField;
    private JPasswordField passwordField_1;
    public Judge judge=new Judge();

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    register frame = new register();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public register() {
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);

        JLabel label = new JLabel("\u7528\u6237\u540D");

        textField = new JTextField();
        textField.setColumns(10);

        JLabel label_1 = new JLabel("*");
        textField.addFocusListener(new FocusAdapter() {
            @Override

            public void focusGained(FocusEvent e) {
                label_1.setText("*");
            }
            @Override
            public void focusLost(FocusEvent e) {
                try {
                    if(!judge.exist(textField.getText().toString())){
                        label_1.setText("is valiable");
                    }
                    else{
                        label_1.setText("the name is used!");
                    }
                } catch (Exception e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            }
        });

        JLabel label_2 = new JLabel("\u5BC6\u7801");

        passwordField = new JPasswordField();

        JLabel label_3 = new JLabel("\u786E\u8BA4\u5BC6\u7801");

        passwordField_1 = new JPasswordField();
        JLabel label_4 = new JLabel("*");
        passwordField_1.addFocusListener(new FocusAdapter() {
            @Override
            public void focusGained(FocusEvent e) {
                label_4.setText("*");
            }
            @Override
            public void focusLost(FocusEvent e) {
                if(new String(passwordField.getPassword()).equals(new String(passwordField_1.getPassword()))){
                    label_4.setText("*");
                }
                else{
                    label_4.setText("the password is not the same,please check it!");
                }
            }
        });

        JButton btnRegister = new JButton("register");
        btnRegister.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {

                try {
                    if(!judge.exist(textField.getText().toString())){
                        String n=textField.getText().toString();
                        String p=new String(passwordField.getPassword());
                        judge.regist(n,p);
                        login lg=new login();
                        lg.setVisible(true);
                        lg.setall(n,p);
                        dispose();
                    }
                    else{
                        JOptionPane.showMessageDialog(null, "the name is exist please try another!");
                    }
                } catch (Exception e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            }

        });
        GroupLayout gl_contentPane = new GroupLayout(contentPane);
        gl_contentPane.setHorizontalGroup(
            gl_contentPane.createParallelGroup(Alignment.LEADING)
                .addGroup(gl_contentPane.createSequentialGroup()
                    .addGap(39)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.TRAILING)
                        .addComponent(btnRegister)
                        .addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING, false)
                            .addGroup(gl_contentPane.createSequentialGroup()
                                .addGap(47)
                                .addGroup(gl_contentPane.createParallelGroup(Alignment.TRAILING)
                                    .addComponent(label_2)
                                    .addComponent(label))
                                .addGap(18)
                                .addGroup(gl_contentPane.createParallelGroup(Alignment.TRAILING, false)
                                    .addComponent(passwordField)
                                    .addComponent(textField, GroupLayout.DEFAULT_SIZE, 100, Short.MAX_VALUE)))
                            .addGroup(gl_contentPane.createSequentialGroup()
                                .addGap(39)
                                .addComponent(label_3)
                                .addGap(18)
                                .addComponent(passwordField_1))))
                    .addGap(18)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
                        .addComponent(label_1)
                        .addComponent(label_4))
                    .addContainerGap(199, Short.MAX_VALUE))
        );
        gl_contentPane.setVerticalGroup(
            gl_contentPane.createParallelGroup(Alignment.LEADING)
                .addGroup(gl_contentPane.createSequentialGroup()
                    .addGap(46)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                        .addComponent(label)
                        .addComponent(textField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                        .addComponent(label_1))
                    .addGap(18)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                        .addComponent(label_2)
                        .addComponent(passwordField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
                    .addGap(26)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                        .addComponent(label_3)
                        .addComponent(passwordField_1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                        .addComponent(label_4))
                    .addGap(34)
                    .addComponent(btnRegister)
                    .addContainerGap(41, Short.MAX_VALUE))
        );
        contentPane.setLayout(gl_contentPane);
    }

}

package addresslist;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class Judge {
    public static void main(String[] args) throws Exception {
        String url ="jdbc:mysql://localhost:3306/login"; //数据库连接字符串
        Class.forName("org.gjt.mm.mysql.Driver").newInstance();  //加载驱动程序
        Connection conn= (Connection) DriverManager.getConnection(url,"tan","tn5201314");  //建立连接
        Statement stmt=(Statement) conn.createStatement();   //创建SQL容器
        String sql="select * from user";   //表为teacher
        ResultSet rs=stmt.executeQuery(sql);   //获得结果集

        while( rs.next() ) {   //处理结果集
            System.out.print(rs.getString("name")+"  ");
            System.out.print(rs.getString("password")+"\n");
        }
        rs.close();     stmt.close();    conn.close();    //关闭次序

      }

    public Connection getConnection()throws Exception{
         String url ="jdbc:mysql://localhost:3306/login"; //数据库连接字符串
         Class.forName("org.gjt.mm.mysql.Driver").newInstance();  //加载驱动程序
         Connection conn= DriverManager.getConnection(url,"tan","tn5201314");
         return conn;
    }
    public boolean exist(String s) throws Exception{
         Connection conn= getConnection();  //建立连接
         Statement stmt=conn.createStatement();   //创建SQL容器
         String sql="select * from user where name='"+s+"'";   //表为user
         ResultSet rs=stmt.executeQuery(sql);   //获得结果集
         if( rs.next() ) {
             rs.close();     stmt.close();    conn.close();
             return true;
         }
         else
         {
             rs.close();     stmt.close();    conn.close();
             return false;
         }
             //关闭次序

    }

    public boolean canlogin(String n,String p) throws Exception{
         Connection conn=getConnection();  //建立连接
         Statement stmt=conn.createStatement();   //创建SQL容器
         String sql="select password from user where name='"+n+"'";   //表为user
         ResultSet rs=stmt.executeQuery(sql);   //获得结果集
         if(rs.next()){
             if(rs.getString("password").equals(p)){
                 rs.close();     stmt.close();    conn.close();
                 return true;
             }
             else{
                 rs.close();     stmt.close();    conn.close();
                 return false;
             }
         }
         else{
             rs.close();     stmt.close();    conn.close();
             return false;
         }

    }

    public void regist(String n,String p) throws Exception{
        Connection conn=getConnection();  //建立连接
        Statement stmt=conn.createStatement();   //创建SQL容器
        String sql="insert into user values('"+n+"','"+p+"')";   //表为user
        stmt.executeUpdate(sql);
        stmt.close();    conn.close();
    }
}