Java基础-25（03）图形用户界面编程GUI

package cn.itcast.util;(1)
import java.awt.Dimension;
import java.awt.Image;
import java.awt.Toolkit;
import javax.swing.JFrame;
/**
 * 专门做界面效果的类
 *
 * @author Administrator
 */
public class UiUtil {
    private UiUtil() {
    }
    //修改窗体的图标
    public static void setFrameImage(JFrame jf) {
        //获取工具类对象
        //public static Toolkit getDefaultToolkit():获取默认工具包。 
        Toolkit tk = Toolkit.getDefaultToolkit();
        //根据路径获取图片
        Image i = tk.getImage("src\\cn\\itcast\\resource\\user.jpg");
        //给窗体设置图片
        jf.setIconImage(i);
    }
        public static void setFrameImage(JFrame jf,String imageName) {
        //获取工具类对象
        //public static Toolkit getDefaultToolkit():获取默认工具包。 
        Toolkit tk = Toolkit.getDefaultToolkit();
        //根据路径获取图片
        Image i = tk.getImage("src\\cn\\itcast\\resource\\"+imageName);
        //给窗体设置图片
        jf.setIconImage(i);
    }
    //设置窗体居中
    public static void setFrameCenter(JFrame jf) {
        /*
         思路：
         A:获取屏幕的宽和高
         B:获取窗体的宽和高
         C:(用屏幕的宽-窗体的宽)/2，(用屏幕的高-窗体的高)/2作为窗体的新坐标。
         */
        //获取工具对象
        Toolkit tk = Toolkit.getDefaultToolkit();
        //获取屏幕的宽和高
        Dimension d = tk.getScreenSize();
        double srceenWidth = d.getWidth();
        double srceenHeigth = d.getHeight();
        //获取窗体的宽和高
        int frameWidth = jf.getWidth();
        int frameHeight = jf.getHeight();
        //获取新的宽和高
        int width = (int) (srceenWidth - frameWidth) / 2;
        int height = (int) (srceenHeigth - frameHeight) / 2;
        //设置窗体坐标
        jf.setLocation(width, height);
    }
}
package cn.itcast.pojo;(2)
public class User {
    private String username;
    private String password;
    public User(){}
    /**
     * @return the username
     */
    public String getUsername() {
        return username;
    }
    /**
     * @param username the username to set
     */
    public void setUsername(String username) {
        this.username = username;
    }
    /**
     * @return the password
     */
    public String getPassword() {
        return password;
    }
    /**
     * @param password the password to set
     */
    public void setPassword(String password) {
        this.password = password;
    }
}
package cn.itcast.dao;(3)
import cn.itcast.pojo.User;
/**
 *
 * @author Administrator
 */
public interface UserDao {
    /**
     * 这是用户登录功能
     *
     * @param username 用户名
     * @param password 密码
     * @return 登录是否成功
     */
    public abstract boolean login(String username, String password);
    /**
     * 这是用户注册功能
     *
     * @param user 被注册的用户信息
     */
    public abstract void regist(User user);
}
package cn.itcast.dao.impl;(4)
import cn.itcast.dao.UserDao;
import cn.itcast.pojo.User;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
/**
 *
 * @author Administrator
 */
public class UserDaoImpl implements UserDao {
    //定义文件
    private static File file = new File("user.txt");
    //类加载的时候就把文件创建
    static {
        try {
            file.createNewFile();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
    @Override
    public boolean login(String username, String password) {
        boolean flag = false;
        BufferedReader br = null;
        try {
            br = new BufferedReader(new FileReader(file));
            String line = null;
            while ((line = br.readLine()) != null) {
                String[] datas = line.split("=");
                if (datas[0].equals(username) && datas[1].equals(password)) {
                    flag = true;
                    break;
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                br.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        return flag;
    }
    @Override
    public void regist(User user) {
        BufferedWriter bw = null;
        try {
            bw = new BufferedWriter(new FileWriter(file, true));
            bw.write(user.getUsername() + "=" + user.getPassword());
            bw.newLine();
            bw.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                bw.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
}