BorderLayout修改各个区域大小办法

BorderLayout控件大小的设置

使用BorderLayout时，中间的面板会随着窗体的变化而变化，其他区域的大小根据添加组件多少而变化。举个例子，现在想将一个面板固定到上边，高度为固定值，这是我们需要设置面板的高度。但是调用面板的 setSize()方法根本没有效果。调用 setMaximumSize()和setMinimumSize()都没有用。
最后才发现应该调用的是 setPreferredSize()才能达到效果。
 

请看例子。

package com.wst.bj;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Toolkit;

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

public class LayoutDemo {

    public static void main(String[] args) {
        new myFrame();
    }
}

/**
 * @author liuyan
 *
 */
class myFrame {

    JFrame jframe = new JFrame("搜索");
    JTextField textField = new JTextField(20);
    JButton jButton = new JButton("转到");
    JButton jButton2 = new JButton("转到2");
    JButton jButton3 = new JButton("转到3");
    JButton jButton4 = new JButton("转到4");
    JTextArea textArea = new JTextArea();
    JPanel jPanel = new JPanel(new BorderLayout(5,20));
    JPanel jPanel2 = new JPanel(new BorderLayout());
    JPanel jPanel3 = new JPanel(new BorderLayout());
    JPanel jPanel4 = new JPanel(new BorderLayout());
    
    
    /**
     * 
     */
    public myFrame() {

        init();
    }
    
    /**
     * 
     */
    private void init()
    {
        jframe.setLayout(new BorderLayout());
        jframe.add(jPanel2, BorderLayout.SOUTH);
        jframe.add(jPanel3, BorderLayout.EAST);
        jframe.add(jPanel4, BorderLayout.WEST);
        jframe.add(jPanel, BorderLayout.NORTH);
        
        jPanel.add(jButton, BorderLayout.EAST);
        jPanel.add(textField, BorderLayout.CENTER);

        jPanel2.add(jButton2);
        jPanel3.add(jButton3);
        jPanel4.add(jButton4);

        jPanel.setPreferredSize(new Dimension(0, 150));
        jPanel2.setPreferredSize(new Dimension(0, 150));
        jPanel3.setPreferredSize(new Dimension(150, 0));
        jPanel4.setPreferredSize(new Dimension(150, 0));

        jframe.add(textArea, BorderLayout.CENTER);
        
        jframe.setVisible(true);
        FrameUtil.initFram(jframe, 500, 700);
    }
}

class FrameUtil
{
    public static void  initFram(JFrame f, int width, int height)
    {
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        f.setVisible(true);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Dimension d = toolkit.getScreenSize();
        int x = (int)d.getWidth();
        int y = (int)d.getHeight();
        f.setBounds((x-width)/2, (y - height )/2, width, height);
    }
}

package com.wst.bj;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Toolkit;

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

public class LayoutDemo {

    public static void main(String[] args) {
        new myFrame();
    }
}

/**
 * @author liuyan
 *
 */
class myFrame {

    JFrame jframe = new JFrame("搜索");
    JTextField textField = new JTextField(20);
    JButton jButton = new JButton("转到");
    JButton jButton2 = new JButton("转到2");
    JButton jButton3 = new JButton("转到3");
    JButton jButton4 = new JButton("转到4");
    JTextArea textArea = new JTextArea();
    JPanel jPanel = new JPanel(new BorderLayout(5,20));
    JPanel jPanel2 = new JPanel(new BorderLayout());
    JPanel jPanel3 = new JPanel(new BorderLayout());
    JPanel jPanel4 = new JPanel(new BorderLayout());
    
    
    /**
     * 
     */
    public myFrame() {

        init();
    }
    
    /**
     * 
     */
    private void init()
    {
        jframe.setLayout(new BorderLayout());
        jframe.add(jPanel2, BorderLayout.SOUTH);
        jframe.add(jPanel3, BorderLayout.EAST);
        jframe.add(jPanel4, BorderLayout.WEST);
        jframe.add(jPanel, BorderLayout.NORTH);
        
        jPanel.add(jButton, BorderLayout.EAST);
        jPanel.add(textField, BorderLayout.CENTER);

        jPanel2.add(jButton2);
        jPanel3.add(jButton3);
        jPanel4.add(jButton4);

//        jPanel.setPreferredSize(new Dimension(0, 150));
//        jPanel2.setPreferredSize(new Dimension(0, 150));
//        jPanel3.setPreferredSize(new Dimension(150, 0));
//        jPanel4.setPreferredSize(new Dimension(150, 0));

        jframe.add(textArea, BorderLayout.CENTER);
        
        jframe.setVisible(true);
        FrameUtil.initFram(jframe, 500, 700);
    }
}

class FrameUtil
{
    public static void  initFram(JFrame f, int width, int height)
    {
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        f.setVisible(true);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Dimension d = toolkit.getScreenSize();
        int x = (int)d.getWidth();
        int y = (int)d.getHeight();
        f.setBounds((x-width)/2, (y - height )/2, width, height);
    }
}