【发布时间】:2014-07-20 19:34:49
【问题描述】:
我尝试在这里通过命令行运行我的课程 (LoginFrame.java):
(我的Java 和Javac 命令在命令行中工作)
首先我使用javac命令编译LoginFrame类:(这个类有main方法)
并使用Java 运行课程:
我在evrironment variable path中设置了jdk 1.7的bin文件夹
(我使用的是 Windows 7)
怎么了?
LoginFrame class:
package Project;
public class LoginFrame extends javax.swing.JFrame implements ActionListener {
String dbUrl = "jdbc:mysql://localhost/Library";
private char[] Password;
private JButton ClearBtn,ExitBtn,LoginBtn;
private JLabel ErrorLbl;
private JComboBox comboBox;
private JLabel lbl1;
private JLabel lbl2;
private JLabel lbl3;
private String[] enterUserInf = new String[4];
private JPasswordField passwordField;
private JTextField usernameTF;
public LoginFrame() {
initComponents();
this.getRootPane().setDefaultButton(LoginBtn);
comboBox.addActionListener(this);
setVisible(true);
}
public static void main(String args[]) throws IOException {
new LoginFrame();
}
private void initComponents() {
//...
}
private void LoginButtonActionPerformed(java.awt.event.ActionEvent evt) {
try {
if (comboBox.getSelectedIndex() == 0) {
ErrorLbl.setText("Select A Model...");
ErrorLbl.setVisible(true);
return;
}
Password = passwordField.getPassword();
if (!passwordControl()) {
return;
}
if (comboBox.getSelectedIndex() == 1) {
if (userEnterCondition(Password)) {
this.setVisible(false);
new BookPage_User(enterUserInf, enterUserInf[0]);
} else {
ErrorLbl.setText("Incorrect Password!");
}
}
if (comboBox.getSelectedIndex() == 2) {
if (adminEnterCondition(Password)) {
this.setVisible(false);
new MainFrame().setVisible(true);
} else {
ErrorLbl.setText("Incorrect Password!");
}
}
} catch (Exception e) {
e.printStackTrace();
ErrorLbl.setText("Enter Correct Input");
}
}
private void ExitButtonActionPerformed(java.awt.event.ActionEvent evt) {
System.exit(0);
}
private void ClearButtonActionPerformed(java.awt.event.ActionEvent evt) {
passwordField.setText("");
}
public boolean passwordControl() {
Password = passwordField.getPassword();
if (String.valueOf(Password).trim().isEmpty()) {
ErrorLbl.setText("Empty Password!");
ErrorLbl.setVisible(true);
return false;
}
return true;
}
public boolean adminEnterCondition(char[] pass) {
Connection con;
PreparedStatement preparedStatement;
ResultSet resultSet;
String query = "Select * From adminLogin";
String password = null;
try {
con = DriverManager.getConnection(...);
preparedStatement = con.prepareStatement(query);
resultSet = preparedStatement.executeQuery();
while (resultSet.next()) {
password = resultSet.getString("ID"); // Get column value by name column name
if (password.equalsIgnoreCase(String.valueOf(pass))) {
return true;
}
}
} catch (SQLException sqle) {
sqle.printStackTrace();
return false;
}
return false;
}
public boolean userEnterCondition(char[] pass) {
Connection con;
PreparedStatement preparedStatement;
ResultSet resultSet;
String query = "Select * from users";
String password = null;
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection(...);
preparedStatement = con.prepareStatement(query);
resultSet = preparedStatement.executeQuery();
while (resultSet.next()) {
password = resultSet.getString("User_ID");
}
} catch (SQLException sqle) {
return false;
} catch (ClassNotFoundException cnfe) {
}
return false;
}
@Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == comboBox) {
if (comboBox.getSelectedIndex() == 1) {
usernameTF.setText("User");
usernameTF.setEditable(false);
passwordField.requestFocusInWindow();
ErrorLbl.setVisible(false);
} else if (comboBox.getSelectedIndex() == 2) {
passwordField.requestFocusInWindow();
}
}
}
}
【问题讨论】:
-
一方面你的程序没有被编译,因为它包含错误。
-
你在编译阶段有编译错误,所以不会生成
.class文件。尝试先修复错误,然后使用javac再次编译,然后使用java运行编译后的类。 -
@SayemAhmed 为什么在我尝试使用
IDE时会运行LoginFrame类? -
@SayemAhmed 我的
NewBook_User和MainFrame和SetMyImage类都存在于目录中,但是为什么会有错误? -
好吧,我建议修复导入并提供三个缺失的类。作为回应,您关闭了命令行并重新打开它。那只是没有帮助。尝试添加缺少的导入。您还缺少三个课程。您可以尝试整天运行它,但在修复编译错误之前它不会运行。
标签: java