创建名为“ControllerX”的bean时出错：

Question

package com.market;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;




@Controller 
public class Controllerx {

    @Autowired
    private View frame;


/*
    private void init() {
        this.frame.addWindowListener(this);
        registerAction(frame.getbEnter(), new AbstractAction() {
            private List<Funcionarios> list; 

            @Override
            public void action() {
                if (!frame.getjLogin().getText().trim().isEmpty() || !frame.getjPassword().getText().trim().isEmpty()) {

                }else {
                    JOptionPane.showMessageDialog(frame, null, "Campo vázio", JOptionPane.INFORMATION_MESSAGE);
                }
            }

            @Override
            public void posAction() {
                cleanUp();
            }
        });
    }
    */
    public void show() {
        frame.setVisible(true);
    }


}

@SpringBootApplication
@EnableAutoConfiguration
public class Market1Application {

    public static void main(String[] args) {
        ConfigurableApplicationContext context = new SpringApplicationBuilder(Market1Application.class).headless(false).run(args);
        Controllerx appLogin = context.getBean(Controllerx.class);
    }

}

package com.market;

import java.awt.FlowLayout;
import java.awt.GridLayout;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

import org.springframework.stereotype.Component;


@Component
public class View extends JFrame{

    private static final int FRAME_WIDTH = 400;
    static final int FRAME_HEIGHT = 350;
    static final int FRAME_X_ORIGIN = 150;
    static final int FRAME_Y_ORIGIN = 150;
    static final int BUTTON_WIDTH = 90;
    static final int BUTTON_HEIGHT = 30;
    private JTextField jLogin;
    private JTextField jPassword;
    private JButton bEnter;
    private JButton bRegister;
    private JPanel loginForm;
    private JLabel loginText;
    private JLabel passwordText;

    public View() {
        setTitle("Login System");
        setSize         (FRAME_WIDTH, FRAME_HEIGHT);
        setLocation     (FRAME_X_ORIGIN, FRAME_Y_ORIGIN);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new FlowLayout());
        setResizable(false);
        initComponents();
    }
    private void initComponents() {
        loginForm = new JPanel(new GridLayout(3,1));
        //buttons
        bRegister = new JButton("Registrar");
        bRegister.setBounds(195, 285, BUTTON_WIDTH, BUTTON_HEIGHT);
        bEnter = new JButton("Registrar");
        bEnter.setBounds(195, 285, BUTTON_WIDTH, BUTTON_HEIGHT);
        //bEnter.setMnemonic(NativeKeyEvent.VC_ENTER);
        //labels
        loginText = new JLabel();
        loginText.setText("Username:");
        passwordText = new JLabel();
        passwordText.setText("Password:");
        //
        loginForm.add(loginText);
        loginForm.add(jLogin);
        loginForm.add(passwordText);
        loginForm.add(jPassword);
        loginForm.add(bEnter);
        loginForm.add(bRegister);
        setVisible(true);
    }

    public void resetForm() {
        jLogin.setText("");
        jPassword.setText("");
    }
    public JTextField getjLogin() {
        return jLogin;
    }
    public void setjLogin(JTextField jLogin) {
        this.jLogin = jLogin;
    }
    public JTextField getjPassword() {
        return jPassword;
    }
    public void setjPassword(JTextField jPassword) {
        this.jPassword = jPassword;
    }
    public JButton getbEnter() {
        return bEnter;
    }
    public void setbEnter(JButton bEnter) {
        this.bEnter = bEnter;
    }

}

我有这些错误编译，我不知道我哪里错了，我只有这3个类

Answer 1

名为jlogin的jTextField变量为null（它是字段，您没有初始化它），这就是为什么在执行操作时使用NPE的原因

loginForm.add(jLogin);

请查看JPanel类的文档-在Add方法部分中有一个信息

public Component add(Component comp)

抛出：NullPointerException-如果comp为空

原因：java.lang.NullPointerException：null

在java.awt.container.additmpl（未知源）

在java.awt.container.add（未知源）