如果并且出现错误

我遇到了我的代码问题。我的代码的逻辑是，当它没有找到我输入的用户名时，会出现一个确认框，真正发生的是当输入的用户名在一行中找到时它没有启动确认框“没关系”但它继续搜索整个每一行并初始化else {statement} btw，我的else语句就是确认框。如果并且出现错误

我的代码写入

shawn | qwerty1234 
cloe | password1234 
jones | shittybrix

当我进入了一个样本data.dat文件“肖恩”它启动我的if语句，“这是正常的” 但它仍然在整个字符串，并输入用户名“肖恩”搜索变得不等于cloe和jones，它分别发出了给我两个确认框的else语句。我想避免这个错误，但我不知道如何。 错误发生时在REGISTER.JAVA

这是我的登录代码：

package login; 

import java.awt.HeadlessException; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.io.*; 
import javax.swing.JOptionPane; 

public class Login extends javax.swing.JFrame { 

    public Login() { 
     initComponents0(); 
    } 

    @SuppressWarnings("unchecked") 
    private void initComponents0() { 

     jLabel1 = new javax.swing.JLabel(); 
     jLabel2 = new javax.swing.JLabel(); 
     uname = new javax.swing.JTextField(); 
     jLabel3 = new javax.swing.JLabel(); 
     login = new javax.swing.JButton(); 
     reset = new javax.swing.JButton(); 
     pwd = new javax.swing.JPasswordField(); 
     setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 
     jLabel1.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N 
     jLabel1.setText("Login Pane"); 
     jLabel2.setText("User Name:"); 
     jLabel3.setText("Password:"); 
     login.setText("Login"); 
     login.addActionListener(new ActionListener() { 
      @Override 
      public void actionPerformed(ActionEvent e) { 
       String un = uname.getText(); 
       try { 
        try (BufferedReader br = new BufferedReader(new Filereader("data.dat"))) { 
         String strLine; 
         while ((strLine = br.readLine()) != null) { 
          if (strLine.startsWith(un)) { 
           JOptionPane.showMessageDialog(null, "Hello: " + un, "Registration", JOptionPane.INFORMATION_MESSAGE); 
          } else { 
           int sel = JOptionPane.showConfirmDialog(null, "It seems that you haven't registered yet? \n Lunch Registration Pane?", "Admin", JOptionPane.INFORMATION_MESSAGE); 
           if (sel == JOptionPane.YES_OPTION) { 
            java.awt.EventQueue.invokeLater(new Runnable() { 
             @Override 
             public void run() { 
              new Register().setVisible(true); 
             } 
            }); 
           } 
          } 
         } 
        } 
       } catch (IOException | HeadlessException ez) { 
        JOptionPane.showMessageDialog(null, "A null file was created in order to \n avoid File Catch errors", "Admin", JOptionPane.INFORMATION_MESSAGE); 
        File file = new File("data.dat"); 
        try { 
         try (FileWriter writer = new FileWriter(file, true)) { 
          String data0 = "null"; 
          String data1 = "null"; 
          writer.write(data0 + " | " + data1 + "\n"); 
         } 
        } catch (IOException | HeadlessException z) { 
         JOptionPane.showMessageDialog(null, e); 
        } 
       } 
      } 
     }); 
     reset.setText("Reset Field"); 

     javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 
     getContentPane().setLayout(layout); 
     layout.setHorizontalGroup(
       layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
       .addGroup(layout.createSequentialGroup() 
       .addContainerGap() 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false) 
       .addComponent(jLabel1) 
       .addGroup(layout.createSequentialGroup() 
       .addComponent(jLabel2) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(uname, javax.swing.GroupLayout.PREFERRED_SIZE, 300, javax.swing.GroupLayout.PREFERRED_SIZE)) 
       .addGroup(layout.createSequentialGroup() 
       .addComponent(jLabel3) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
       .addGroup(layout.createSequentialGroup() 
       .addComponent(login, javax.swing.GroupLayout.PREFERRED_SIZE, 137, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
       .addComponent(reset, javax.swing.GroupLayout.PREFERRED_SIZE, 137, javax.swing.GroupLayout.PREFERRED_SIZE)) 
       .addComponent(pwd)))) 
       .addContainerGap(30, Short.MAX_VALUE))); 
     layout.setVerticalGroup(
       layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
       .addGroup(layout.createSequentialGroup() 
       .addContainerGap() 
       .addComponent(jLabel1) 
       .addGap(18, 18, 18) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
       .addComponent(jLabel2) 
       .addComponent(uname, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)) 
       .addGap(18, 18, 18) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
       .addComponent(jLabel3) 
       .addComponent(pwd, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)) 
       .addGap(18, 18, 18) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
       .addComponent(login) 
       .addComponent(reset)) 
       .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))); 

     pack(); 
    } 

    /** 
    * @param args the command line arguments 
    */ 
    public static void main(String args[]) { 
     java.awt.EventQueue.invokeLater(new Runnable() { 
      @Override 
      public void run() { 
       new Login().setVisible(true); 
      } 
     }); 
    } 
    // Variables declaration - do not modify 
    private javax.swing.JLabel jLabel1; 
    private javax.swing.JLabel jLabel2; 
    private javax.swing.JLabel jLabel3; 
    private javax.swing.JButton login; 
    private javax.swing.JPasswordField pwd; 
    private javax.swing.JButton reset; 
    private javax.swing.JTextField uname; 
    // End of variables declaration 
}

这个它的注册码它启动时，我确认框中

/* 
* To change this template, choose Tools | Templates 
* and open the template in the editor. 
*/ 
package login; 

import java.awt.HeadlessException; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.io.File; 
import java.io.FileWriter; 
import java.io.IOException; 
import javax.swing.JOptionPane; 

/** 
* 
* @author Jfetizanan 
*/ 
class Register extends javax.swing.JFrame { 

    /** 
    * Creates new form GUIREG 
    */ 
    public Register() { 
     initComponents(); 
    } 

    /** 
    * This method is called from within the constructor to initialize the form. 
    * WARNING: Do NOT modify this code. The content of this method is always 
    * regenerated by the Form Editor. 
    */ 
    @SuppressWarnings("unchecked") 
    private void initComponents() { 
     jLabel1 = new javax.swing.JLabel(); 
     jLabel2 = new javax.swing.JLabel(); 
     unamereg = new javax.swing.JTextField(); 
     jLabel3 = new javax.swing.JLabel(); 
     pwdreg = new javax.swing.JTextField(); 
     submit = new javax.swing.JButton(); 
     resetreg = new javax.swing.JButton(); 
     setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 
     jLabel1.setFont(new java.awt.Font("Tahoma", 0, 18)); // NOI18N 
     jLabel1.setText("Registration Pane"); 
     jLabel2.setText("User Name:"); 
     jLabel3.setText("Password:"); 
     submit.setText("Submit"); 
     submit.addActionListener(new ActionListener() { 
      @Override 
      public void actionPerformed(ActionEvent e) { 
       System.out.println("Runned"); 
       File file = new File("data.dat"); 
       try { 
        try (FileWriter writer = new FileWriter(file, true)) { 
         String data0 = unamereg.getText(); 
         String data1 = pwdreg.getText(); 
         writer.write(data0 + " | " + data1 + "\n"); 
        } 
        JOptionPane.showMessageDialog(null, "Registered", "Registration", JOptionPane.INFORMATION_MESSAGE); 
       } catch (IOException | HeadlessException z) { 
        JOptionPane.showMessageDialog(null, e); 
       } 
      } 
     }); 
     resetreg.setText("Reset Field"); 

     javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 
     getContentPane().setLayout(layout); 
     layout.setHorizontalGroup(
       layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
       .addGroup(layout.createSequentialGroup() 
       .addContainerGap() 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false) 
       .addComponent(jLabel1) 
       .addGroup(layout.createSequentialGroup() 
       .addComponent(jLabel2) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(unamereg)) 
       .addGroup(layout.createSequentialGroup() 
       .addComponent(jLabel3) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
       .addComponent(pwdreg) 
       .addGroup(layout.createSequentialGroup() 
       .addComponent(submit, javax.swing.GroupLayout.PREFERRED_SIZE, 139, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) 
       .addComponent(resetreg, javax.swing.GroupLayout.PREFERRED_SIZE, 139, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addGap(0, 0, Short.MAX_VALUE))))) 
       .addContainerGap(42, Short.MAX_VALUE))); 
     layout.setVerticalGroup(
       layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
       .addGroup(layout.createSequentialGroup() 
       .addContainerGap() 
       .addComponent(jLabel1) 
       .addGap(18, 18, 18) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
       .addComponent(jLabel2) 
       .addComponent(unamereg, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)) 
       .addGap(18, 18, 18) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
       .addComponent(jLabel3) 
       .addComponent(pwdreg, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)) 
       .addGap(18, 18, 18) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
       .addComponent(submit) 
       .addComponent(resetreg)) 
       .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))); 

     pack(); 
    } 
    /** 
    * @param args the command line arguments 
    */ 
    // Variables declaration - do not modify 
    private javax.swing.JLabel jLabel1; 
    private javax.swing.JLabel jLabel2; 
    private javax.swing.JLabel jLabel3; 
    private javax.swing.JTextField pwdreg; 
    private javax.swing.JButton resetreg; 
    private javax.swing.JButton submit; 
    private javax.swing.JTextField unamereg; 
    // End of variables declaration 
}

来源

2012-08-26 JFetz2191

你能格式化你的代码并重新发布吗？艰难地阅读这种方式 –

一个建议：我试图重新格式化您的代码，并最终放弃。请使用适当的缩进格式进行格式化，以便不熟悉代码的人可读。 –

请简化您的代码。创建一个以更简单的方式重现问题的示例。删除所有这些GUI的东西。 – davidbuzatto

是点击管理通过这个大混乱找到问题。在你的if语句中弹出hello'blah'，你需要让它跳出while循环，并移动else语句。在while循环中复制else语句中的whats（仅仅因为它不匹配第一个人，并不意味着它不会匹配后一个，所以不要直到最后）。所以有这样的：

BufferedReader br = new BufferedReader(
     new InputStreamReader(fstream)); 
String strLine; 
boolean registered = false; 
while ((strLine = br.readLine()) != null) { 
    if (strLine.startsWith(un)) { 
     registered = true; 
     break; 
    } 
} 
if(registered) { 
    //blah 
} else { 
    //blah 
}

此外，你应该改变午餐登记启动注册;）

在回答您的意见，这是由于该行：

setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

你有在你的两个框架中，只要你关闭它就会停止JVM。你希望这样做你的登录框架（如果他们关闭登录窗口，停止程序），但不是注册窗口。为此，您只需要javax.swing.WindowConstants.DISPOSE_ON_CLOSE，这表示它将在关闭时清除帧（很好的清理）。如果所有框架都放弃了，JVM将会结束（假设没有其他线程正在运行），所以只要Login保持打开状态，它就不应该退出。

来源

2012-08-26 15:30:26

是的，它编译没有错误 – JFetz2191

啊，它有很多Java 7中，我看到 –

@ JFetz2191看到我的编辑，删除旧信息，并把我刚刚找到的 –

如果并且出现错误

回答

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