Java使用弹簧布局管理器

Java使用弹簧布局管理器：

package com.han;      import java.awt.Container;   import java.awt.event.WindowAdapter;   import java.awt.event.WindowEvent;      import javax.swing.JButton;   import javax.swing.JFrame;   import javax.swing.JLabel;   import javax.swing.JScrollPane;   import javax.swing.JTextArea;   import javax.swing.JTextField;   import javax.swing.Spring;   import javax.swing.SpringLayout;      /**   * 使用弹簧布局管理器   * @author HAN   *   */   public class SpringLayout_3 extends JFrame {          /**       *        */       private static final long serialVersionUID = -6045918631932051025L;          public SpringLayout_3() {           // TODO Auto-generated constructor stub            Container container = getContentPane();           SpringLayout springLayout = new SpringLayout();           container.setLayout(springLayout);           JLabel topicLabel = new JLabel("topic :");           JLabel contentLabel = new JLabel("content :");           final JTextField textField = new JTextField(30);           JTextArea textArea = new JTextArea(3, 30);           JScrollPane scrollPane = new JScrollPane();           scrollPane.setViewportView(textArea);           textArea.setLineWrap(true);           final JButton confirmButton = new JButton("confirm");           JButton cancelButton = new JButton("cancel");           Spring st = Spring.constant(10);           Spring st2 = Spring.constant(30);           container.add(topicLabel);           springLayout.putConstraint(SpringLayout.NORTH, topicLabel, st,                    SpringLayout.NORTH, container);           springLayout.putConstraint(SpringLayout.WEST, topicLabel, st,                    SpringLayout.WEST, container);           container.add(textField);           springLayout.putConstraint(SpringLayout.WEST, textField, st2,                    SpringLayout.EAST, topicLabel);           springLayout.putConstraint(SpringLayout.NORTH, textField, 0,                    SpringLayout.NORTH, topicLabel);           springLayout.putConstraint(SpringLayout.EAST, textField, Spring.minus(st),                    SpringLayout.EAST, container);           container.add(contentLabel);           springLayout.putConstraint(SpringLayout.WEST, contentLabel, 0,                    SpringLayout.WEST, topicLabel);           springLayout.putConstraint(SpringLayout.NORTH, contentLabel, st,                    SpringLayout.SOUTH, topicLabel);           container.add(scrollPane);           springLayout.putConstraint(SpringLayout.NORTH, scrollPane, 0,                    SpringLayout.NORTH, contentLabel);           springLayout.putConstraint(SpringLayout.WEST, scrollPane, 0,                    SpringLayout.WEST, textField);           springLayout.putConstraint(SpringLayout.EAST, scrollPane, Spring.minus(st),                    SpringLayout.EAST, container);           container.add(confirmButton);           springLayout.putConstraint(SpringLayout.SOUTH, scrollPane, Spring.minus(st),                    SpringLayout.NORTH, confirmButton);           springLayout.putConstraint(SpringLayout.EAST, confirmButton, Spring.minus(st),                    SpringLayout.EAST, container);           springLayout.putConstraint(SpringLayout.SOUTH, confirmButton, Spring.minus(st),                    SpringLayout.SOUTH, container);           container.add(cancelButton);           springLayout.putConstraint(SpringLayout.EAST, cancelButton, Spring.minus(st),                    SpringLayout.WEST, confirmButton);           springLayout.putConstraint(SpringLayout.NORTH, cancelButton, 0,                    SpringLayout.NORTH, confirmButton);                       // make the text field focused every time the window is activated            addWindowFocusListener(new WindowAdapter() {                  @Override               public void windowGainedFocus(WindowEvent e) {                   // TODO Auto-generated method stub                    textField.requestFocus();               }              });       }          /**       * @param args       */       public static void main(String[] args) {           // TODO Auto-generated method stub            SpringLayout_3 frame = new SpringLayout_3();           frame.setTitle("使用弹簧布局管理器");           frame.setVisible(true);           frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);           frame.setBounds(100, 100, 600, 300);       }      }