一个关于用户名密码读取写入的问题~~~

Question

在做个用户注册的界面时，要把用户名和密码保存到文本文件中，我的问题是在保存前要做个判断用户名是否存在，还有用户登陆时要判断用户名和密码是否正确，该怎么做？
这个用数据库很容易，用文本就不知该怎么做了………………在io在有个串行化接口Serializable，是不是用这个啊？
我弄了好久都弄不好，请高手指点~~

Answer 1

把文本文件按行读取，然后比较新的用户名和密码，保存时可以将用户名密码以特殊形式进行存贮，如www-123456主要是为了方便比较,每行不要有空格。

Answer 2

public void jButton1_actionPerformed(ActionEvent e) {
       String name=t1.getText();
       String pwd=t2.getText();
       Student stu=new Student(name,pwd);
       Student test;
        try {
            FileOutputStream file_out = new FileOutputStream("ttt.txt", true);
            ObjectOutputStream object_out = new ObjectOutputStream(file_out);            FileInputStream file_in=new FileInputStream("ttt.txt");
            ObjectInputStream object_in=new ObjectInputStream(file_in);            
            
                          while(true)
                          {
                                  try{
                                          test=(Student)object_in.readObject();                                  if (stu.name.equals(test.name))
                                  {
                                          System.out.println("用户已经存在！");
                                          break;
                                  }
                                  }catch(EOFException ee){
                                 object_out.writeObject(stu);
                                  System.out.println("结束");
                                  break;                                  }                          }        }         catch(ClassNotFoundException event)
        {  System.out.println("不能读出对象");
         }
        catch (IOException event) {
            System.out.println("can not read file:  " + event);
        }
    }
}

Answer 3

FileOutputStream file_out = new FileOutputStream("ttt.txt", true);
            ObjectOutputStream object_out = new ObjectOutputStream(file_out);            FileInputStream file_in=new FileInputStream("ttt.txt");
            ObjectInputStream object_in=new ObjectInputStream(file_in);
不好，

Answer 4

自己解决了   String name = jTextField1.getText();
        String pwd = jTextField2.getText();
        String dir = jTextField3.getText();
        String fr = null;
        String fw = null;
        String fd = null;
        String dl = null;
        String dc = null;
        String dd = null;        if (jCheckBox5.isSelected()) {
            fr = "只读";
        }
        if (jCheckBox6.isSelected()) {
            fw = "只写";
        }
        if (jCheckBox8.isSelected()) {
            fd = "删除";
        }
        if (jCheckBox7.isSelected()) {
            dc = "创建";
        }
        if (jCheckBox1.isSelected()) {
            dl = "列表";
        }
        if (jCheckBox2.isSelected()) {
            dd = "目录删除";
        }        User user = new User(name, pwd, dir, fr, fw, fd, dc, dl, dd);
        // goods_list.add(user);        try {
            FileInputStream come_in = new FileInputStream(
                    "user.txt");
            ObjectInputStream in = new ObjectInputStream(come_in);
            goods_list = (LinkedList) in.readObject();
            in.close();
        } catch (ClassNotFoundException event) {} catch (IOException event) {}
        for (int i = 0; i < goods_list.size(); i++) {
            User temp = (User) goods_list.get(i);
            if (temp.name.equals(name)) {
                
                System.out.println("用户已经存在！！！");
                return;
            }        }
        try {
            goods_list.add(user);
            FileOutputStream file = new FileOutputStream(
                    "user.txt");
            ObjectOutputStream out = new ObjectOutputStream(file);
            out.writeObject(goods_list);
            out.close();
            System.out.println("用户添加成功！！！");
            jTextField1.setText("");
            jTextField2.setText("");
            jTextField3.setText("");        } catch (IOException event) {}