JAVA--图书管理员登陆系统

效果图：

先用sqlyog连接数据库创建新的数据库并创建一个表，如图：

 

数据库连接代码

package com.shine.util;

import java.sql.Connection;
import java.sql.DriverManager;

/**
 * 数据库工具类
 * @author 75476
 *
 */
public class Db_util {
    private String dburl="jdbc:mysql://localhost:3306/gb_book";//数据库地址连接
    private String dbUserName="root";
    private String dbPassword="754764";
    private String jdbcName="com.mysql.jdbc.Driver";
    /**
     * 获取数据库连接
     * @return
     * @throws Exception
     */
    public Connection getCon()throws Exception{
        Class.forName(jdbcName);
        Connection con=    DriverManager.getConnection(dburl, dbUserName, dbPassword);
        return con;
        
    }
    /**
     * 关闭数据库连接
     * @param con
     * @throws Exception
     */
    public void closeCon(Connection con) throws Exception{
        if(con!=null)
            con.close();
    }
    public static void main(String[] args) {
        Db_util dbutil=new Db_util();
        try {
            dbutil.getCon();
            System.out.println("数据库连接成功");
        } catch (Exception e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
            System.out.println("数据库连接失败");
        }
        
    }
}

用户实体代码，

package com.shine.model;
/**
 * 用户实体
 * @author 75476
 *
 */
public class User {
    private int id;
    private String userName;
    private String Password;
    
    public User() {
        super();
        
    }
    
    public User(String userName, String password) {
        super();
        this.userName = userName;
        Password = password;
    }

    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getPassword() {
        return Password;
    }
    public void setPassword(String password) {
        Password = password;
    }
    
    
}

用户dao类

package com.shine.dao;



import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import com.shine.model.User;

/**
 * 用户Dao类
 * @author 75476
 *
 */
public class UserDao {
    /**
     * 登陆验证
     * @param con
     * @param user
     * @return
     * @throws Exception
     */
    public User login(Connection con,User user)throws Exception{
        User resultUser=null;
        String sql="select * from t_user where userName=? and Password=?";
        PreparedStatement pstmt =con.prepareStatement(sql);
        pstmt.setString(1, user.getUserName());
        pstmt.setString(2, user.getPassword());
        ResultSet rs=pstmt.executeQuery();
        if(rs.next()){
            resultUser=new User();
            resultUser.setId(rs.getInt("id"));
            resultUser.setUserName(rs.getString("userName"));
            resultUser.setPassword(rs.getString("Password"));
        }
        return resultUser;
        
    }

}

登陆界面设计，动作监听，这里用的是windowbuilder插件

package com.shine.view;

import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;

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 com.shine.dao.UserDao;
import com.shine.model.User;
import com.shine.util.Db_util;
import com.shine.util.Stringutil;

public class logOn extends JFrame {

    private Db_util dbutil=new Db_util();
    private UserDao userDao=new UserDao();
    private JPanel contentPane;
    private JTextField userNameTxt;
    private JPasswordField PasswordTxt;

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

    /**
     * Create the frame.
     */
    public logOn() {
        setResizable(false);
        setTitle("u7BA1u7406u5458u767Bu9646");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 665, 532);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        
        JLabel lblNewLabel = new JLabel("u56FEu4E66u7BA1u7406u7CFBu7EDF");
        lblNewLabel.setFont(new Font("宋体", Font.BOLD, 22));
        lblNewLabel.setIcon(new ImageIcon(logOn.class.getResource("/imags/558952.gif")));
        
        JLabel lblNewLabel_1 = new JLabel("u7528u6237u540D");
        lblNewLabel_1.setIcon(new ImageIcon(logOn.class.getResource("/imags/userName.png")));
        lblNewLabel_1.setFont(new Font("宋体", Font.BOLD, 20));
        
        JLabel lblNewLabel_2 = new JLabel("u5BC6  u7801");
        lblNewLabel_2.setIcon(new ImageIcon(logOn.class.getResource("/imags/password.png")));
        lblNewLabel_2.setFont(new Font("宋体", Font.BOLD, 20));
        
        userNameTxt = new JTextField();
        userNameTxt.setColumns(10);
        
        PasswordTxt = new JPasswordField();
        
        JButton btnNewButton = new JButton("u767B u9646");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                logInActionperformed(e);
            }
        });
        btnNewButton.setIcon(new ImageIcon(logOn.class.getResource("/imags/login.png")));
        btnNewButton.setFont(new Font("宋体", Font.BOLD, 18));
        
        JButton button = new JButton("u91CD u7F6E");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                resetValueActionperformed(e);
            }
        });
        button.setIcon(new ImageIcon(logOn.class.getResource("/imags/reset.png")));
        button.setFont(new Font("宋体", Font.BOLD, 18));
        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(163)
                            .addComponent(lblNewLabel))
                        .addGroup(gl_contentPane.createSequentialGroup()
                            .addGap(101)
                            .addGroup(gl_contentPane.createParallelGroup(Alignment.TRAILING)
                                .addGroup(gl_contentPane.createSequentialGroup()
                                    .addComponent(lblNewLabel_1)
                                    .addGap(19))
                                .addGroup(gl_contentPane.createSequentialGroup()
                                    .addComponent(lblNewLabel_2)
                                    .addGap(18)))
                            .addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
                                .addComponent(userNameTxt, GroupLayout.DEFAULT_SIZE, 166, Short.MAX_VALUE)
                                .addComponent(PasswordTxt, GroupLayout.PREFERRED_SIZE, 267, GroupLayout.PREFERRED_SIZE)))
                        .addGroup(Alignment.TRAILING, gl_contentPane.createSequentialGroup()
                            .addContainerGap()
                            .addComponent(btnNewButton)
                            .addGap(94)
                            .addComponent(button, GroupLayout.PREFERRED_SIZE, 110, GroupLayout.PREFERRED_SIZE)))
                    .addGap(179))
        );
        gl_contentPane.setVerticalGroup(
            gl_contentPane.createParallelGroup(Alignment.LEADING)
                .addGroup(gl_contentPane.createSequentialGroup()
                    .addGap(35)
                    .addComponent(lblNewLabel)
                    .addGap(54)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                        .addComponent(lblNewLabel_1)
                        .addComponent(userNameTxt, GroupLayout.PREFERRED_SIZE, 41, GroupLayout.PREFERRED_SIZE))
                    .addGap(47)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                        .addComponent(lblNewLabel_2)
                        .addComponent(PasswordTxt, GroupLayout.PREFERRED_SIZE, 41, GroupLayout.PREFERRED_SIZE))
                    .addGap(68)
                    .addGroup(gl_contentPane.createParallelGroup(Alignment.BASELINE)
                        .addComponent(button, GroupLayout.PREFERRED_SIZE, 37, GroupLayout.PREFERRED_SIZE)
                        .addComponent(btnNewButton, GroupLayout.PREFERRED_SIZE, 37, GroupLayout.PREFERRED_SIZE))
                    .addContainerGap(95, Short.MAX_VALUE))
        );
        contentPane.setLayout(gl_contentPane);
    }
    /**
     * 登陆事件
     * @param e
     */
private void logInActionperformed(ActionEvent e) {
        String userName=this.userNameTxt.getText();
        String Password=new String(this.PasswordTxt.getPassword());
        if(Stringutil.isEmpty(userName)){
            JOptionPane.showMessageDialog(null, "用户名不可为空");
            return;
            
        }
        if(Stringutil.isEmpty(Password)){
            JOptionPane.showMessageDialog(null, "密码不可为空");
            return;
        }
        User user=new User(userName,Password);
        Connection con=null;
        try {
            con=dbutil.getCon();
            User currentUser=userDao.login(con, user);
            if(currentUser!=null){
                JOptionPane.showMessageDialog(null, "登陆成功");
                
            }else{
                JOptionPane.showMessageDialog(null, "用户名或密码错误！");
            }
        } catch (Exception e1) {
            // TODO 自动生成的 catch 块
            e1.printStackTrace();
        }
    }

/**
 * 重置事件处理
 * @param e
 */
    protected void resetValueActionperformed(ActionEvent evt) {
        this.userNameTxt.setText("");
        this.PasswordTxt.setText("");
    }
}

  

判断输入框是否为空

package com.shine.util;
/**
 * 字符串工具类
 * @author 75476
 *
 */
public class Stringutil {
    public static  boolean isEmpty(String str){
    if(str==null||"".equals(str.trim())){
        return true;
        
    }else{
        return false;
    }
    }
    public static  boolean isNotEmpty(String str){
        if(str!=null||"".equals(str.trim())){
            return true;
            
        }else{
            return false;
        }
        }
    }

附上一些常用的快捷键 

Alt + /  内容提示：
Ctrl + 1   提示
Ctrl + shift + O  导包
Ctrl + Shift + F  格式化代码块
Alt+上下键  代码位置调换 
Ctrl+/   添加/除去单行注释 
Ctrl+Shift+/   添加多行注释 
Ctrl+Shift+   删除多行注释 
window->reset perspective  重置透视图 
Ctrl+Shift+X   更改为大写
Ctrl+Shift+Y  更改为小写 
 Ctrl+Alt+向下键   复制行
Ctrl+单击 需要查看源码的类
Ctrl+Shift+T  需要查看源码的类

shift+tab 左对齐