我最近在设计GUI，里面用到了java的IO，但是有一个问题一直没有解决，还请高手帮帮我。我是实在没有办法了，实在很郁闷。

Question

我用NetBeans设计的，我希望在点击 jButton1 的时候
首先判断 jPasswordField1 和 jPasswordField2 里的密码是否一样，如果不一样在jLabel1里高亮显示提示。
如果一样则读取jTxtField里的用户名，然后在一个uid.txt里寻找是否有这个用户名，如果有，在jLabel1里高亮显示提示。
如果没有则可以在uid.txt的末尾添加这个用户名，并且生成一个以用户名为名的二进制文件，在其中保存密码。
但是我每次想保存的时候都是出现异常....还请高手能帮我解决一下啦。这个问题困扰我很久了。
我一直想找老师的，可是我们的老师整天不见人....
我郁闷了很久了，还希望能有人使我拨开乌云见灿烂阳关啦！
谢谢啦
下面是代码：
（FIREFOX用不了那个代码网站的添加功能？？？）
/*
 * Register.java
 *
 * Created on 2008年5月31日, 下午4:31
 */package newtest1;import java.awt.Color;
import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.ObjectOutputStream;
import java.io.PrintWriter;/**
 *
 * @author  kumuking
 */
public class Register extends javax.swing.JFrame {
    
    
    public Register() {
        initComponents();
    }
    
    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        if(jPasswordField1.getText().equals(jPasswordField2.getText())){
            try
            {
                BufferedReader getUid = new BufferedReader(new FileReader("uid.txt"));
                PrintWriter output = new PrintWriter(new FileOutputStream("uid.txt"),true);
                ObjectOutputStream pw = new ObjectOutputStream(new FileOutputStream(jTextField1.getText()));
                String id = getUid.readLine();
                while(id != null)
                {
                    if(jTextField1.getText().equals(id))
                    {
                        jPanel1.setBackground(Color.RED);
                        jLabel1.setText("ERROR : The entered username has existed! TRY AGAIN!");
                    }
                    else
                    {
                        output.println(jTextField1.getText());
                        pw.writeUTF(jPasswordField1.getText());
                        getUid.close();
                        output.close();
                        pw.close();
                    }
                }
            }
            catch(Exception e1)
            {
                jPanel1.setBackground(Color.RED);
                jLabel1.setText("ERROR : Opening files failed or creating files error!");
            }   
        }
        else
        {
            jPanel1.setBackground(Color.RED);
            jLabel1.setText("ERROR : Enter two separate passwords! TRY AGAIN!");
        }
    }    private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
        System.exit(0);
    }    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
        jTextField1.setText("");
        jPasswordField1.setText("");
        jPasswordField2.setText("");
    }
        public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Register().setVisible(true);
            }
        });
    }
        private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JButton jButton3;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JPanel jPanel3;
    private javax.swing.JPasswordField jPasswordField1;
    private javax.swing.JPasswordField jPasswordField2;
    private javax.swing.JTextField jTextField1;    
}

Answer 1

刚才显示说的我内容太长，这里是界面的设置 部分1
    private void initComponents() {        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jPanel2 = new javax.swing.JPanel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jLabel4 = new javax.swing.JLabel();
        jTextField1 = new javax.swing.JTextField();
        jPasswordField1 = new javax.swing.JPasswordField();
        jPasswordField2 = new javax.swing.JPasswordField();
        jPanel3 = new javax.swing.JPanel();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
        jButton3 = new javax.swing.JButton();        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);        jLabel1.setText("            Please register first, and then log in.");        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 343, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(21, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jLabel1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 32, Short.MAX_VALUE)
        );        jLabel2.setText("User Name:");        jLabel3.setText("Password:");        jLabel4.setText("Confirm:");        jTextField1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jTextField1ActionPerformed(evt);
            }
        });        javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
        jPanel2.setLayout(jPanel2Layout);
        jPanel2Layout.setHorizontalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jLabel4, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 86, Short.MAX_VALUE)
                    .addComponent(jLabel3, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 86, Short.MAX_VALUE)
                    .addComponent(jLabel2, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 86, Short.MAX_VALUE))
                .addGap(18, 18, 18)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(jPasswordField2)
                    .addComponent(jPasswordField1)
                    .addComponent(jTextField1, javax.swing.GroupLayout.DEFAULT_SIZE, 199, Short.MAX_VALUE))
                .addGap(61, 61, 61))
        );
        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGap(24, 24, 24)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 35, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(18, 18, 18)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 34, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jPasswordField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(18, 18, 18)
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel4, javax.swing.GroupLayout.DEFAULT_SIZE, 31, Short.MAX_VALUE)
                    .addComponent(jPasswordField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap())
        );        
 

Answer 2

这里是部分2jButton1.setText("OK");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });        jButton2.setText("RESET");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });        jButton3.setText("EXIT");
        jButton3.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton3ActionPerformed(evt);
            }
        });        javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
        jPanel3.setLayout(jPanel3Layout);
        jPanel3Layout.setHorizontalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel3Layout.createSequentialGroup()
                .addContainerGap(54, Short.MAX_VALUE)
                .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 63, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(36, 36, 36)
                .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 75, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(42, 42, 42)
                .addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 66, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(40, 40, 40))
        );
        jPanel3Layout.setVerticalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel3Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 30, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jButton3)
                    .addComponent(jButton2))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jPanel3, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jPanel2, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jPanel1, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );        pack();
    }

Answer 3

} catch (Exception e1) {
e1.printStackTrace();你应该打印出异常信息加上如上红色所示那句代码
估计是找不到文件 你把那个txtx文件 放到d盘根目录下
然后改成下面的 就可以了BufferedReader getUid = new BufferedReader(new FileReader(
"d:/uid.txt"));
PrintWriter output = new PrintWriter(new FileOutputStream(
"d:/uid.txt"), true);

Answer 4

interpb
你好，谢谢你回答我的问题。
可是...
我按你的方法作了，可是还是不行。
你在你的电脑上，测试能通过吗？

Answer 5

我用 e1.getMessage()
显示是 uid.txt (No such file or directory)
可是我明明有一个这么文件阿
原来是放在同一个文件夹的
后来按你的方法放在了 e盘根目录
可是一样...

Answer 6

 BufferedReader getUid = new BufferedReader(new FileReader("e:/uid.txt")); 
                PrintWriter output = new PrintWriter(new FileOutputStream("e:/uid.txt"),true);放在e盘根目录的话就要改成上面的
把 路径写对 

Answer 7

试过啦
现在没有异常抛出啦可是又有一个问题出现啦...
这次是直接把uid.txt里的信息全部刷没了..
我在默认构造器明明加了一个 true 阿...