异常与File类实战

来源：互联网发布：aws与阿里云差别编辑：程序博客网时间：2024/06/10 12:20

用File类的文件操作和异常处理来制作一个<<登录窗口>>

import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.ButtonGroup;import javax.swing.ButtonModel;import javax.swing.JLabel;import javax.swing.JOptionPane;import javax.swing.JTextField;public class ButtonAction implements ActionListener{    public JTextField jf;    public JTextField jf2;    public ButtonGroup bg;    public String command;    public ButtonAction(JTextField jf4,JTextField jf24,ButtonGroup bg1){        this.jf=jf4;        this.jf2=jf24;        bg=bg1;    }    public void actionPerformed(ActionEvent e) {        String name=jf.getText();        String pwd=jf2.getText();        ButtonModel cba=bg.getSelection();        command=e.getActionCommand();        System.out.println(command);        if("pic1".equals(command)){            if(checkLogin(name,pwd)){                JOptionPane.showMessageDialog(null, "登陆成功");            }else{                JOptionPane.showMessageDialog(null,"登陆失败");            }        }else if("pic2".equals(command)){            Login.databases.put(name, pwd);            if(checkLogin2(name,pwd)){                JOptionPane.showMessageDialog(null, "注册失败");            }else{                JOptionPane.showMessageDialog(null, "注册成功");            //  Login.databases.            }        }    }    public boolean checkLogin2(String name,String pwd){        if(Login.databases.containsKey(name)){            String password=Login.databases.get(name);            if(password.equals(pwd)){                return false;            }else{                return true;            }        }        return true;    }    public boolean checkLogin(String name,String pwd){        if(Login.databases.containsKey(name)){            String password=Login.databases.get(name);            if(password.equals(pwd)){                return true;            }        }        return false;           }}

package Login;import java.awt.FlowLayout;import java.util.HashMap;import javafx.scene.layout.Background;import javax.swing.ButtonGroup;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JTable;import javax.swing.JTextField;public class Login extends JFrame{    public static HashMap<String,String> databases=new HashMap<String,String>();    static{        for(int i=0;i<10;i++){            databases.put("user"+i,"pwd"+i);        }    }    public void initment(){        this.setSize(300,150);        this.setDefaultCloseOperation(3);        this.setLocationRelativeTo(null);        this.setLayout(new FlowLayout(FlowLayout.LEFT));        this.setTitle("登录界面");        JLabel jtfUser=new JLabel("账号:");        this.add(jtfUser);        JTextField jf=new JTextField(20);        this.add(jf);        JLabel jtfPwd=new JLabel("密码:");        this.add(jtfPwd);        JTextField jf2=new JTextField(20);        this.add(jf2);        ButtonGroup bg=new ButtonGroup();        JButton button=new JButton();        button.setText("登录");        this.add(button);        button.setActionCommand("pic"+1);        bg.add(button);        JButton button2=new JButton();        button2.setText("注册");        this.add(button2);        button2.setActionCommand("pic"+2);        bg.add(button2);        ButtonAction ba=new ButtonAction(jf,jf2,bg);        button.addActionListener(ba);        button2.addActionListener(ba);        this.setVisible(true);    }}

package Login;public class test {    public static void main(String[]args){        Login login=new Login();        login.initment();    }

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