所以我正在尝试使用 Net-beans GUI Builder 构建一个简单的 Java 程序——一个登录界面应用程序。如果您想查看界面设计，请查看此图像。
编辑：净豆IDE 8.2
目的：以在名称和密码输入，他们匹配的证书存储和处理在不同的类（具有public volatile String持有"true"并"false"作为有价值的，因为我真的无法实现适当的布尔一对原因-“实际参数与形式参数不匹配”（我分配了一个方法到布尔变量) )，并为每次成功登录打开一个特定网页，这是特定于特定 ID 的。[ [注意：Credentials.java 中的密码以二进制形式存储，并使用脚本转换为 ASCII，结果与用户输入的密码匹配]]
包含的类： Java_007.java（主类，管理整个可视化界面并将输入数据发送到Credentials.java）和Credentials.java（处理输入并将ID 输入和密码输入与存储在其中的配置文件相匹配）
代码：
Java_007.java（我在最左边的代码中做了注释）
import java.awt.Desktop;
import java.net.URL;
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author walker_001
*/
public class Java_007 extends javax.swing.JFrame {
/**
* Creates new form Java_007
*/
public Java_007() {
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")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
//ONLY ASSIGNMENT PART ALONG WITH THE STATUS OF THE OBJECTS(i.e. public, private..)
back = new javax.swing.JPanel();
decoration = new javax.swing.JPanel();
close = new javax.swing.JButton();
Title = new javax.swing.JLabel();
name = new javax.swing.JLabel();
password = new javax.swing.JLabel();
n = new javax.swing.JTextField();
ps = new javax.swing.JPasswordField();
submit = new javax.swing.JButton();
invalidinput2 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setAlwaysOnTop(true);
setMinimumSize(new java.awt.Dimension(400, 250));
setUndecorated(true);
setResizable(false);
back.setBackground(new java.awt.Color(255, 255, 255));
back.setBorder(javax.swing.BorderFactory.createMatteBorder(1, 1, 1, 1, new java.awt.Color(0, 204, 255)));
back.setForeground(new java.awt.Color(255, 255, 255));
back.setMaximumSize(new java.awt.Dimension(400, 250));
back.setMinimumSize(new java.awt.Dimension(400, 250));
back.setPreferredSize(new java.awt.Dimension(400, 250));
decoration.setBackground(java.awt.Color.white);
decoration.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 2, 0, new java.awt.Color(0, 204, 255)));
decoration.setForeground(new java.awt.Color(255, 255, 255));
decoration.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
public void mouseDragged(java.awt.event.MouseEvent evt) {
decorationMouseDragged(evt);
}
});
decoration.addMouseListener(new java.awt.event.MouseAdapter() {
public void mousePressed(java.awt.event.MouseEvent evt) {
decorationMousePressed(evt);
}
});
close.setBackground(new java.awt.Color(0, 0, 0));
close.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Close.png"))); // NOI18N
close.setBorder(null);
close.setBorderPainted(false);
close.setContentAreaFilled(false);
close.setFocusPainted(false);
close.setFocusable(false);
close.addFocusListener(new java.awt.event.FocusAdapter() {
public void focusLost(java.awt.event.FocusEvent evt) {
closeFocusLost(evt);
}
});
close.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseExited(java.awt.event.MouseEvent evt) {
closeMouseExited(evt);
}
public void mousePressed(java.awt.event.MouseEvent evt) {
closeMousePressed(evt);
}
public void mouseReleased(java.awt.event.MouseEvent evt) {
closeMouseReleased(evt);
}
});
close.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
closeActionPerformed(evt);
}
});
Title.setBackground(new java.awt.Color(255, 255, 255));
Title.setFont(new java.awt.Font("Segoe UI", 1, 18)); // NOI18N
Title.setForeground(new java.awt.Color(0, 204, 255));
Title.setText("Login");
Title.setToolTipText("");
javax.swing.GroupLayout decorationLayout = new javax.swing.GroupLayout(decoration);
decoration.setLayout(decorationLayout);
decorationLayout.setHorizontalGroup(
decorationLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, decorationLayout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(Title)
.addGap(139, 139, 139)
.addComponent(close, javax.swing.GroupLayout.PREFERRED_SIZE, 33, javax.swing.GroupLayout.PREFERRED_SIZE))
);
decorationLayout.setVerticalGroup(
decorationLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(decorationLayout.createSequentialGroup()
.addGap(0, 0, Short.MAX_VALUE)
.addComponent(close, javax.swing.GroupLayout.PREFERRED_SIZE, 32, javax.swing.GroupLayout.PREFERRED_SIZE))
.addComponent(Title, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
name.setFont(new java.awt.Font("Segoe UI", 1, 14)); // NOI18N
name.setForeground(new java.awt.Color(0, 204, 255));
name.setText("Name : ");
password.setFont(new java.awt.Font("Segoe UI", 1, 14)); // NOI18N
password.setForeground(new java.awt.Color(0, 204, 255));
password.setText("Password : ");
n.setFont(new java.awt.Font("Segoe UI", 1, 14)); // NOI18N
n.setHorizontalAlignment(javax.swing.JTextField.CENTER);
n.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 2, 0, new java.awt.Color(0, 204, 255)));
n.setCaretColor(new java.awt.Color(0, 204, 255));
n.setMaximumSize(new java.awt.Dimension(192, 26));
n.setMinimumSize(new java.awt.Dimension(192, 26));
n.setPreferredSize(new java.awt.Dimension(192, 26));
n.setSelectedTextColor(new java.awt.Color(255, 255, 255));
n.setSelectionColor(new java.awt.Color(0, 204, 255));
n.addFocusListener(new java.awt.event.FocusAdapter() {
public void focusGained(java.awt.event.FocusEvent evt) {
nFocusGained(evt);
}
});
ps.setFont(new java.awt.Font("Segoe UI", 1, 14)); // NOI18N
ps.setHorizontalAlignment(javax.swing.JTextField.CENTER);
ps.setToolTipText("");
ps.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 2, 0, new java.awt.Color(0, 204, 255)));
ps.setCaretColor(new java.awt.Color(0, 204, 255));
ps.setCursor(new java.awt.Cursor(java.awt.Cursor.TEXT_CURSOR));
ps.setEchoChar('\u2219');
ps.setSelectedTextColor(new java.awt.Color(255, 255, 255));
ps.setSelectionColor(new java.awt.Color(0, 204, 255));
ps.addFocusListener(new java.awt.event.FocusAdapter() {
public void focusGained(java.awt.event.FocusEvent evt) {
psFocusGained(evt);
}
});
submit.setBackground(new java.awt.Color(0, 0, 0));
submit.setFont(new java.awt.Font("Segoe UI", 1, 14)); // NOI18N
submit.setForeground(new java.awt.Color(0, 204, 255));
submit.setText("Submit");
submit.setToolTipText("");
submit.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 2, 0, new java.awt.Color(0, 204, 255)));
submit.setContentAreaFilled(false);
submit.setFocusPainted(false);
submit.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
submitActionPerformed(evt);
}
});
invalidinput2.setFont(new java.awt.Font("Segoe UI", 1, 12)); // NOI18N
invalidinput2.setForeground(new java.awt.Color(255, 0, 0));
invalidinput2.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
javax.swing.GroupLayout backLayout = new javax.swing.GroupLayout(back);
back.setLayout(backLayout);
backLayout.setHorizontalGroup(
backLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(decoration, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, backLayout.createSequentialGroup()
.addGap(60, 60, 60)
.addGroup(backLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(submit, javax.swing.GroupLayout.PREFERRED_SIZE, 62, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(backLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addGroup(backLayout.createSequentialGroup()
.addGroup(backLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(name)
.addComponent(password))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(backLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(ps)
.addComponent(n, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
.addComponent(invalidinput2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
.addGap(60, 60, 60))
);
backLayout.setVerticalGroup(
backLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(backLayout.createSequentialGroup()
.addComponent(decoration, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(invalidinput2, javax.swing.GroupLayout.PREFERRED_SIZE, 16, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(37, 37, 37)
.addGroup(backLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(name)
.addComponent(n, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(29, 29, 29)
.addGroup(backLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(password)
.addComponent(ps, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addComponent(submit, javax.swing.GroupLayout.PREFERRED_SIZE, 32, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(27, 27, 27))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(back, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(back, javax.swing.GroupLayout.DEFAULT_SIZE, 266, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
private void closeActionPerformed(java.awt.event.ActionEvent evt) {
System.exit(0);
}
//真正的代码从这里开始。下面继续 Java_007.java 的代码......
//user defined variables...start
int xmouse;
int ymouse;
Credentials c= new Credentials();
//user defined variables...end
private void closeMousePressed(java.awt.event.MouseEvent evt) {
close.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Close_pressed.png")));
}
private void decorationMouseDragged(java.awt.event.MouseEvent evt) {
int x= evt.getXOnScreen();
int y= evt.getYOnScreen();
setLocation(x - xmouse, y - ymouse);
}
private void decorationMousePressed(java.awt.event.MouseEvent evt) {
xmouse= evt.getX();
ymouse= evt.getY();
}
private void submitActionPerformed(java.awt.event.ActionEvent evt) {
String a= n.getText();
String b= ps.getText();
if (a.equals("") || b.equals("")){
if (a.equals("") && b.equals("")){
n.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 1, 0, new java.awt.Color(255, 0, 0)));
ps.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 1, 0, new java.awt.Color(255, 0, 0)));
invalidinput2.setText("Please enter your name and password.");
}
else if(a.equals("")){
n.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 1, 0, new java.awt.Color(255, 0, 0)));
invalidinput2.setText("Please enter your name.");
}
else if(b.equals("")){
ps.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 1, 0, new java.awt.Color(255, 0, 0)));
invalidinput2.setText("Please enter your password.");
}
}
else{
if (a.equals(Credentials.a1) && c.encoded.equals("true")){
try {
Desktop.getDesktop().browse(new URL("https://inbox.google.com/").toURI());
} catch (Exception e) {}
System.exit(0);
}
else if (a.equals(Credentials.a2) && c.encoded.equals("true")){
try {
Desktop.getDesktop().browse(new URL("https://www.google.com/").toURI());
} catch (Exception e) {}
System.exit(0);
}
else if (a.equals(Credentials.a3) && c.encoded.equals("true")){
try {
Desktop.getDesktop().browse(new URL("https://images.google.com/").toURI());
} catch (Exception e) {}
System.exit(0);
}
else{
invalidinput2.setText("Invalid Credentials");
//System.out.println(c.id);System.out.println(Credentials.pd);System.out.println(Credentials.passwrd);System.out.println(Credentials.psv);System.out.println(Credentials.encoded);
}
n.setText("");
ps.setText("");
}
}
private void nFocusGained(java.awt.event.FocusEvent evt) {
n.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 1, 0, new java.awt.Color(0, 255, 255)));
ps.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 1, 0, new java.awt.Color(0, 255, 255)));
invalidinput2.setText("");
}
private void psFocusGained(java.awt.event.FocusEvent evt) {
n.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 1, 0, new java.awt.Color(0, 255, 255)));
ps.setBorder(javax.swing.BorderFactory.createMatteBorder(0, 0, 1, 0, new java.awt.Color(0, 255, 255)));
invalidinput2.setText("");
}
private void closeMouseExited(java.awt.event.MouseEvent evt) {
close.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Close.png")));
}
private void closeMouseReleased(java.awt.event.MouseEvent evt) {
close.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Close.png")));
}
private void closeFocusLost(java.awt.event.FocusEvent evt) {
close.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Close.png")));
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Java_007.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Java_007.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Java_007.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Java_007.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Java_007().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JLabel Title;
private javax.swing.JPanel back;
private javax.swing.JButton close;
private javax.swing.JPanel decoration;
private javax.swing.JLabel invalidinput2;
public static javax.swing.JTextField n;
private javax.swing.JLabel name;
private javax.swing.JLabel password;
public static javax.swing.JPasswordField ps;
public volatile javax.swing.JButton submit;
// End of variables declaration
}
凭证.java
public class Credentials{
public static String a1= "Strix";
public static String a2= "PK";
public static String a3= "Molt";
static String b1= "0010001100110000011110000101011101001101001100010011000001011000";
static String b2= "00110000001100000011000000110010001101100011100000110100";
static String b3= "00110001001100100011001100110100";
volatile String id= Java_007.n.getText();
volatile String pd= Java_007.ps.getText();
volatile String passwrd= passwrd(id);
volatile String psv= psV(passwrd);
public volatile String encoded= post(psv);
public static void main(String[] args) {
//System.out.println(id);System.out.println(pd);System.out.println(passwrd);System.out.println(psv);System.out.println(encoded);
}
private String passwrd(String password){
if (id.equals(a1)){
password= b1;
}
else if (id.equals(a2)){
password= b2;
}
else if (id.equals(a3)){
password= b3;
}else{}
return password;
}
private String psV(String e){
StringBuilder b = new StringBuilder();
int len = passwrd.length();
int i = 0;
while (i + 8 <= len) {
char c = convert(passwrd.substring(i, i+8));
i+=8;
b.append(c);
e= b.toString();
}
return e;
}
private static char convert(String bs) {
return (char)Integer.parseInt(bs, 2);
}
private String post(String r){
boolean go= false;
if (id.equals(a1)){
if (pd.equals(psv)){
go= true;
}
else{
go= false;
}
}
else if (id.equals(a2)){
if (pd.equals(psv)){
go= true;
}
else{
go= false;
}
}
else if (id.equals(a3)){
if (pd.equals(psv)){
go= true;
}
else{
go= false;
}
}
else{
go= false;
}
if (go == true){
r= "true";
}
else{
r= "false";
}
return r;
}
}
问题：该程序根本不显示。Net-Beans 在编译时没有显示任何错误，但是当我运行程序时，输出窗格显示NullPointerException：
run:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Credentials.<init>(Credentials.java:10)
at Java_007.<init>(Java_007.java:240)
at Java_007$9.run(Java_007.java:361)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
BUILD SUCCESSFUL (total time: 1 second)
从昨天开始我一直在互联网上搜索，但我找不到真正的解决方案。我确定这与Credentials.java类中某些变量的 volatile 声明有关，也可能与Java_007.java文件中的处理相关的其他一些声明有关，但我不确定到底是什么问题。任何帮助将不胜感激！谢谢您阅读此篇。请随意索取我可能未提供的任何其他信息。
所以事实证明，我在创建方法/实例之前就调用了它们......我尝试了一些我能想到的事情，例如不使用直接 getter 而是访问变量...... NullPointerException 已解决，但有一些代码规划问题。所以现在我要重新考虑整个计划并转储这段代码。大家好！
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