Question

我想将客户名称传递给班级StartSearchByName2，我正在使用netbeans IDE。客户名称来自Jtextfield。请给我一些解决方案。我有关于Java的基本知识，我坚持了大约6个小时。

Class StartSByName

 public class StartSByName extends javax.swing.JFrame {
 String Customername;
  public void close() {
   WindowEvent winClosingEvent = new WindowEvent(this, WindowEvent.WINDOW_CLOSING);
    Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(winClosingEvent);
}


     String NameM(String Name){
     Name = Customername;
     System.out.println(Name);
     return Name;
 }
public StartSByName() {
    initComponents();
}

private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {                                         
jButtonAction5(evt);
}                                                                                 
public void jButtonAction5(ActionEvent evt) {
    Connection con = null;
    PreparedStatement st = null;
    ResultSet rs = null;

    try {
        Class.forName("com.mysql.jdbc.Driver");
        con=DriverManager.getConnection("jdbc:mysql://localhost:3306/holt", "root", "");
        st=con.prepareStatement("select * from customers where Name=?");
        Customername = jTextField1.getText();
        st.setString(1, Customername);
        rs = st.executeQuery();        
        jTextField1.setText(Customername);
        if (rs.next()) {
         JOptionPane.showMessageDialog(null, "Customer Found With ID = " + rs.getString("ID"));
          jTextField1.setText(Customername);
            String Name = null;
           NameM(Name);  // Calling NameM 
           StartSearchByName2 SB = new StartSearchByName2();
            SB.setVisible(true);
            close(); 
        } else {
            JOptionPane.showMessageDialog(null, "Customer Does Not Exist");
        }
    } catch (ClassNotFoundException | SQLException | HeadlessException ex) {
        System.out.println("Error " + ex);
    }   }

类StartSearchByName2

public class StartSearchByName2 extends javax.swing.JFrame {
String Name;
StartSByName Sb= new StartSByName();
public StartSearchByName2() {
    System.out.println(Sb.NameM(Name));

输出

Tabish Raza // This Output from StartSByName Class and when calling NameM
null // From StartSearchByName2, its twice null, but i called once and it is not giving me Correct String.
null //

Answer 1

    public class StartSearchByName2 extends javax.swing.JFrame {

    String Name;

    public StartSearchByName2(String pName) {
        Name = pName;
        System.out.println(Name);
}

在第一堂课中更改以下语句

StartSearchByName2 SB = new StartSearchByName2();

到

StartSearchByName2 SB = new StartSearchByName2(Name);

将字符串从TextField传递到另一个类

1 个答案: