菜鸟求助,如何实现将按一个按钮,将一个FRAME中的一个PANEL变成预先编好的另外一个PANEL.以及按了一个按钮以后,弹出一个对话框之类的操作

a.java
public class a extends javax.swing.JFrame {
    
        public a() {
        initComponents();
    }
    
       private void initComponents() {
        jButton1 = new javax.swing.JButton();
        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        jButton1.setText("\u5207\u6362\u9875\u9762");
        jButton1.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                jButton1MouseClicked(evt);
            }
        });        jLabel1.setText("\u9875\u97621");        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(171, 171, 171)
                .addComponent(jLabel1)
                .addContainerGap(187, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                .addContainerGap(137, Short.MAX_VALUE)
                .addComponent(jLabel1)
                .addGap(117, 117, 117))
        );        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(68, 68, 68)
                .addComponent(jButton1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 171, Short.MAX_VALUE)
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap(229, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addComponent(jButton1)
                        .addGap(178, 178, 178))
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addContainerGap())))
        );
        pack();
    }// </editor-fold>                            private void jButton1MouseClicked(java.awt.event.MouseEvent evt) {                                      
      javax.swing.JPanel t=new b();
      t.setVisible(true);
      jPanel1=t;
      this.repaint();
    }                                     
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new a().setVisible(true);
            }
        });
    }                    
    private javax.swing.JButton jButton1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JPanel jPanel1;
                
    
}用NETBEANS拖的,实在看不懂NETBEANS的布局管理器是怎么工作的.
另外新建个JAVA文件,是一个JPANEL
public class b extends javax.swing.JPanel {    public b() {
        initComponents();
    }
                      
    private void initComponents() {
        jLabel1 = new javax.swing.JLabel();        jLabel1.setText("\u9875\u97622");        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
        this.setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(194, Short.MAX_VALUE)
                .addComponent(jLabel1)
                .addGap(176, 176, 176))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(134, 134, 134)
                .addComponent(jLabel1)
                .addContainerGap(151, Short.MAX_VALUE))
        );
    }              
         
    private javax.swing.JLabel jLabel1;
                 
    
}
很菜的鸟,希望大家帮助下,先谢谢了.希望高手们推荐点学GUI的资料哈