设计模式的学习-登录的重构
登录模块在实际项目开发中很常见，请按照教材28页利用单一职责原则重构后的类图实现这一模块。
java代码的实现
Customer
public class Customer { private String uname; private String pas; public String getUname() { return uname; } public void setUname(String uname) { this.uname = uname; } public String getPas() { return pas; } public void setPas(String pas) { this.pas = pas; } public Customer(String uname, String pas) { super(); this.uname = uname; this.pas = pas; } public Customer() { // TODO Auto-generated constructor stub } }
CustomerDao
import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; import java.util.List; public class CustomerDao { private DBUtil util; private Connection conn; private Statement st; private PreparedStatement prs; private ResultSet rs; public boolean findCustomers(String uname,String pas){ boolean flag=false; try { conn=DBUtil.getConnection(); String sql="select *from tbl_cus where uname = ? and pas = ?"; prs = conn.prepareStatement(sql); prs.setString(1, uname); prs.setString(2, pas); rs = prs.executeQuery(); while(rs.next()) { Customer cus1=new Customer(); cus1.setUname(rs.getString("uname")); cus1.setPas(rs.getString("pas")); if(cus1.getPas()!=null&&cus1.getPas().equals(pas)) { flag=true; } } }catch(SQLException e) { e.printStackTrace(); }finally { util.close(st, conn, rs,prs); } return flag; } public CustomerDao() { // TODO Auto-generated constructor stub } }
DBUtil
import java.io.FileReader;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
public class DBUtil {
private static String url;
private static String password;
private static String user;
private static String driver;
static {
try {
//读取资源文件，获取值
//1.创建properties集合类
Properties pro=new Properties();
//2.加载文件
//获取src路径下文件的方式--》classLoader类加载器
ClassLoader classloader=DBUtil.class.getClassLoader();
java.net.URL res=classloader.getResource("jdbc.properties");
String path=res.getPath();
pro.load(new FileReader(path));
//3.获取数据并且赋值
url=pro.getProperty("url");
password=pro.getProperty("password");
user=pro.getProperty("user");
driver=pro.getProperty("driver");
//4.注册驱动
Class.forName(driver);
}catch(IOException exception) {
exception.printStackTrace();
}catch(ClassNotFoundException e) {
e.printStackTrace();
}
}
/*
获取连接，连接对象
*/
public static Connection getConnection() throws SQLException{
return DriverManager.getConnection(url,user,password);
}
/*
*
* 释放资源
*/
public static void close(Statement st,Connection conn) {
if(st!=null) {
try {
st.close();
}catch(SQLException e) {
e.printStackTrace();;
}
}
if(conn!=null) {
try {
conn.close();
}catch(SQLException e) {
e.printStackTrace();
}
}
}
/*
* 重载close
*/
/*
* 正着开，倒着关。所以先关Statement，后关Connection
*
*/
public static void close(Statement st,Connection conn,ResultSet rs) {
if(rs!=null) {
try {
rs.close();
}catch(SQLException e) {
e.printStackTrace();
}
}
if(st!=null) {
try {
st.close();
}catch(SQLException e) {
e.printStackTrace();;
}
}
if(conn!=null) {
try {
conn.close();
}catch(SQLException e) {
e.printStackTrace();
}
}
}
public static void close(Statement st,Connection conn,ResultSet rs,PreparedStatement prs) {
if(rs!=null) {
try {
rs.close();
}catch(SQLException e) {
e.printStackTrace();
}
}
if(prs!=null) {
try {
prs.close();
}catch(SQLException e) {
e.printStackTrace();
}
}
if(st!=null) {
try {
st.close();
}catch(SQLException e) {
e.printStackTrace();;
}
}
if(conn!=null) {
try {
conn.close();
}catch(SQLException e) {
e.printStackTrace();
}
}
}
}
LoginForm
import java.awt.*; import java.awt.event.*; import javax.swing.*; public class LoginForm extends JFrame { private static final long serialVersionUID = 1L; private CustomerDao dao = new CustomerDao(); //设置按钮组件 private JButton jb=new JButton("登录"); //添加一个登录按钮 private JButton button=new JButton("重置"); //添加一个确定按钮 //设置文本框组件 private JTextField username = new JTextField();//用户名框 private JPasswordField password = new JPasswordField();//密码框：为加密的*** JLabel user_name=new JLabel("账号：");//设置左侧用户名文字 JLabel pass_word=new JLabel("密码：");//设置左侧密码文字 public void init() { /* 组件绝对位置 */ user_name.setBounds(50, 70, 300, 25); pass_word.setBounds(50, 130, 200, 25); username.setBounds(110, 70, 300, 25);//设置用户名框的宽，高，x值，y值 password.setBounds(110, 130, 300, 25);//设置密码框的宽，高，x值，y值 button.setBounds(315, 225, 90, 20);//设置确定按钮的宽，高，x值，y值 jb.setBounds(95, 225, 90, 20);//设置确定按钮的宽，高，x值，y值 /* 组件透明化*/ user_name.setOpaque(false); pass_word.setOpaque(false); //监听事件 jb.addActionListener(new ActionListener(){ //为确定按钮添加监听事件 @SuppressWarnings("deprecation") public void actionPerformed(ActionEvent arg0) { validate(username.getText().trim(),password.getText().trim()); } }); //重置按钮 button.addActionListener(new ActionListener(){ //为重置按钮添加监听事件 //同时清空name、password的数据 public void actionPerformed(ActionEvent arg0) { // TODO 自动生成方法存根 username.setText(""); password.setText(""); } }); } public void display() { JFrame f =new JFrame(); f.setTitle("登录页面"); //窗口退出行为 f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //设置窗口大小不可变 f.setResizable(false); //设置窗口打开居中 f.setLocationRelativeTo(null); //窗口大小 f.setSize(500, 300); init(); //添加组件 Container contentPanel= new Container();//添加一个contentPanel容器 contentPanel.setLayout(null);//设置添加的contentPanel容器为流布局管理器 contentPanel.add(user_name); contentPanel.add(pass_word); contentPanel.add(username); contentPanel.add(password); contentPanel.add(jb); contentPanel.add(button); f.add(contentPanel); //展示窗口 f.setVisible(true); } public void validate(String username,String password) { if(username.trim().length()==0||password.trim().length()==0){ JOptionPane.showMessageDialog(null, "用户名,密码不允许为空"); return; } if(dao.findCustomers(username, password)) { JOptionPane.showMessageDialog(null, "登录成功！"); }else { JOptionPane.showMessageDialog(null, "用户名或密码错误"); } } }
MainClass
public class MainClass { public MainClass() { // TODO Auto-generated constructor stub } public static void main(String[]args) { LoginForm loginForm=new LoginForm() ; //调用 loginForm.display(); } }
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