西电JAVA第四次上机作业实验报告.doc

JAVA第四次上机作业实验报告一、上机内容Java GUI编程实验编写程序，利用JTextField和JPasswordField分别接收用户输入的用户名和密码，并对用户输入的密码进行检验。对于每个用户名有三次密码输入机会。要求： 1、所有用户名和密码信息都预先存放在文件passwords.txt中，使用文件流读入；2、当三次密码输入均错误时，弹出模式化对话框阻塞窗口，并在对话框关闭时同时关闭窗口。二、上机分析1、组件定义及界面显示内容：public class Login private JFrame frame;private JLabel label1;private JLabel label2;private JLabel label3;private JPasswordField jf;private JTextField jt;private JButton yes;private JButton no;private int i=0;public Login()frame=new JFrame(用户登陆);label1=new JLabel(西电芝麻开门);label2=new JLabel( 用户名：);label3=new JLabel(密 码：);jf=new JPasswordField(15);jt=new JTextField(15);yes=new JButton(登录);no=new JButton(取消);init();addEventHandler();2、界面格局设计：public void init()JPanel north=new JPanel();JPanel center=new JPanel();JPanel south=new JPanel();north.setLayout(new FlowLayout();center.setLayout(new FlowLayout(2);south.setLayout(new FlowLayout();north.add(label1);center.add(label2);center.add(jt);center.add(label3);center.add(jf);south.add(yes);south.add(no);frame.setLayout(new BorderLayout();frame.add(north,BorderLayout.NORTH);frame.add(center,BorderLayout.CENTER);frame.add(south,BorderLayout.SOUTH);public void showMe()label1.setFont(new Font(隶体,Font.BOLD,16);frame.setLocation(600, 400);frame.setSize(250,200);frame.setResizable(false);/不能改变窗口大小frame.setVisible(true);/frame.pack();/设置窗口为最适尺寸frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);3、操作后显示设计当三次密码输入均错误时，弹出模式化对话框阻塞窗口，并在对话框关闭时同时关闭窗口。public void addEventHandler()yes.addActionListener(new ActionListener() SuppressWarnings(deprecation) public void actionPerformed(ActionEvent e) if(jt.getText().equals(abc)&jf.getText().equals(123)JOptionPane.showMessageDialog(null, 登陆成功); else if(i=2) System.exit(0); else i+; JOptionPane.showMessageDialog(null, 登陆失败,你还有+(3-i)+次机会););no.addActionListener(new ActionListener()public void actionPerformed(ActionEvent e) System.exit(0););public static void main(String args)new Login().showMe();三、代码如下：import java.awt.BorderLayout;import java.awt.Color;import java.awt.FlowLayout;import java.awt.Font;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;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 java.io.*;public class Login private JFrame frame;private JLabel label1;private JLabel label2;private JLabel label3;private JPasswordField jf;private JTextField jt;private JButton yes;private JButton no;private int i=0;public Login()frame=new JFrame(用户登陆);label1=new JLabel(西电芝麻开门);label2=new JLabel( 用户名：);label3=new JLabel(密 码：);jf=new JPasswordField(15);jt=new JTextField(15);yes=new JButton(登录);no=new JButton(取消);init();addEventHandler();public void init()JPanel north=new JPanel();JPanel center=new JPanel();JPanel south=new JPanel();north.setLayout(new FlowLayout();center.setLayout(new FlowLayout(2);south.setLayout(new FlowLayout();north.add(label1);center.add(label2);center.add(jt);center.add(label3);center.add(jf);south.add(yes);south.add(no);frame.setLayout(new BorderLayout();frame.add(north,BorderLayout.NORTH);frame.add(center,BorderLayout.CENTER);frame.add(south,BorderLayout.SOUTH);public void showMe()label1.setFont(new Font(隶体,Font.BOLD,16);frame.setLocation(600, 400);frame.setSize(250,200);frame.setResizable(false);/不能改变窗口大小frame.setVisible(true);/frame.pack();/设置窗口为最适尺寸frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);public void addEventHandler()yes.addActionListener(new ActionListener() SuppressWarnings(deprecation) public void actionPerformed(ActionEvent e) if(jt.getText().equals(abc)&jf.getText().equals(123) JOptionPane.showMessageDialog(null, 登陆成功); else if(i=2) System.exit(0); else i+; JOptionPane.showMessageDialog(null, 登陆失败,你还有+(3-i)+次机会); );no.addActionListen