package com.zky.www.view;
import java.awt.*;

import javax.swing.*;

import com.zky.www.bean.User;
import com.zky.www.dao.Dao;

import java.awt.event.*;
public class UpdatePassIFrame extends JInternalFrame{
    
    private JLabel lbusername=new JLabel("用户名:");
    private JTextField txtusername=new JTextField();
    
    private JLabel lboldpassword=new JLabel("旧密码:");
    private JPasswordField txtoldpassword=new JPasswordField();
    
    private JLabel lbnewpassword=new JLabel("新密码:");
    private JPasswordField txtnewpassword=new JPasswordField();
    
    private JLabel lbnewpassword2=new JLabel("确认密码:");
    private JPasswordField txtnewpassword2=new JPasswordField();
    
    
    private JButton btnupdate=new JButton("修改");
    private JButton btnreset=new JButton("重置");
    
    User user=LoginFrame.getUser();   //新建User对象
    UpdatePassIFrame()
    {
        this.setSize(new Dimension(320,300));
        this.setLocation(240, 120);
        this.setClosable(true);   //设置窗口可以关闭
        this.setMaximizable(false);    //设置子窗体不允许最大化
        this.setIconifiable(true);   //设置子窗体可以图标化
        this.setTitle("修改密码");
        
        lbusername.setBounds(50, 40, 60, 25);
        txtusername.setBounds(120, 40, 140,25);
        txtusername.setText(user.getUsername());   //将当前登录用户名放入用户名文本框中
        txtusername.setEditable(false);    //设置使调用这个方法的控件不允许被编辑
        
        lboldpassword.setBounds(50, 75, 60, 25);
        txtoldpassword.setBounds(120, 75, 140, 25);
        
        lbnewpassword.setBounds(50, 110, 60, 25);
        txtnewpassword.setBounds(120, 110, 140, 25);
        
        lbnewpassword2.setBounds(50, 145, 60, 25);
        txtnewpassword2.setBounds(120, 145, 140, 25);
        
        btnupdate.setBounds(80, 200, 60, 25);
        btnreset.setBounds(150, 200, 60, 25);
        
        Container cont=this.getContentPane();
        cont.setLayout(null);
        cont.add(lbusername);
        cont.add(txtusername);
        
        cont.add(lboldpassword);
        cont.add(txtoldpassword);
        
        cont.add(lbnewpassword);
        cont.add(txtnewpassword);
        
        cont.add(lbnewpassword2);
        cont.add(txtnewpassword2);
        
        
        cont.add(btnupdate);
        cont.add(btnreset);
        
        btnupdate.addActionListener(new UpdatePasswordAction());   //将修改按钮加入监听事件 
        
        this.setVisible(true);
    }
    private class UpdatePasswordAction implements ActionListener
    {
        
        @Override
        public void actionPerformed(ActionEvent e) {
            String username=user.getUsername();  //用户名是从数据库获取的当前User名字
            String oldpassword=txtoldpassword.getText().trim();  //旧密码为用户输入
            String newpassword=txtnewpassword.getText().trim();
            String newpassword2=txtnewpassword2.getText().trim();
            
            if(null!=oldpassword &&!"".equals(oldpassword))
            {
              if(oldpassword.equals(user.getPassword())){
                if(null!=newpassword&&!"".equals(newpassword)&&newpassword.equals(newpassword2))
                {
                    int flag=Dao.updatePassword(username,newpassword);
                    if(flag>0)
                    {
                        JOptionPane.showMessageDialog(null, "密码修改成功！");
                        user.setPassword(newpassword);
                    }else{
                        JOptionPane.showMessageDialog(null, "密码修改失败！");
                    }
                }
                else{
                    JOptionPane.showMessageDialog(null, "两次密码不一致或密码为空！");
                    txtnewpassword.setText("");
                    txtnewpassword2.setText("");
                    txtnewpassword.requestFocus();
                }
              }else{
                  JOptionPane.showMessageDialog(null, "旧密码不正确！");
                  txtoldpassword.setText("");
                  txtoldpassword.requestFocus();
              }
            }else
            {
                JOptionPane.showMessageDialog(null, "旧密码不能为空！");
                 txtoldpassword.setText("");
                 txtoldpassword.requestFocus();
            }
            
        }
        
    }

}

这是一个小的修改密码的程序，数据库我才用的是mycycle，如上面代码以及异常图片所示，在修改的时候遇到了空指针问题，即使User对象的问题，但是不知道咋解决，求大神帮忙，多谢！