重写JSplitPane的BasicSplitPaneUI

import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.LayoutManager;

import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JSplitPane;
import javax.swing.UIManager;
import javax.swing.border.Border;
import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.basic.BasicSplitPaneDivider;
import javax.swing.plaf.basic.BasicSplitPaneUI;

import sun.swing.DefaultLookup;

public class MySplitPaneUI extends BasicSplitPaneUI {

	private static final Color BG_COLOR = Color.BLACK;
	public JButton theL$UButton, theR$DButton;

	public MySplitPaneUI() {
		super();
	}

	public static ComponentUI createUI(JComponent c) {
		return new MySplitPaneUI();
	}

	@Override
	public void paint(Graphics g, JComponent c) {
		super.paint(g, c);
		g.setColor(Color.BLACK);
		int width = c.getWidth();
		int height = c.getHeight();
		g.drawRect(3, 3, width - 6, height - 6);
	}

	/**
	 * Creates the default divider.
	 */
	@Override
	public BasicSplitPaneDivider createDefaultDivider() {
		return new MyBasicSplitPaneDivider(this);
	}

	private class MyBasicSplitPaneDivider extends BasicSplitPaneDivider {

		private static final long serialVersionUID = 1L;
		private int oneTouchSize, oneTouchOffset;
		boolean centerOneTouchButtons;
		/* Center空白区域 */
		private int area_x, area_y;

		@SuppressWarnings("unchecked")
		public MyBasicSplitPaneDivider(MySplitPaneUI ui) {
			super(ui);
			oneTouchSize = DefaultLookup.getInt(ui.getSplitPane(), ui, "SplitPane.oneTouchButtonSize", ONE_TOUCH_SIZE);
			oneTouchOffset = DefaultLookup.getInt(ui.getSplitPane(), ui, "SplitPane.oneTouchButtonOffset", ONE_TOUCH_OFFSET);
			centerOneTouchButtons = DefaultLookup.getBoolean(ui.getSplitPane(), ui, "SplitPane.centerOneTouchButtons", true);
			//oneTouchSize = ONE_TOUCH_SIZE;
			//oneTouchOffset = ONE_TOUCH_OFFSET;
			//centerOneTouchButtons = true;
			setLayout(new DividerLayout());
			setBasicSplitPaneUI(ui);
			orientation = splitPane.getOrientation();
			setCursor((orientation == JSplitPane.HORIZONTAL_SPLIT) ? Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR) : Cursor
					.getPredefinedCursor(Cursor.S_RESIZE_CURSOR));
			setBackground(UIManager.getColor("SplitPane.background"));
		}

		/**
		 * Creates and return an instance of JButton that can be used to collapse the right component in the split pane.
		 */
		@SuppressWarnings("serial")
		@Override
		protected JButton createRightOneTouchButton() {
			JButton b = new JButton() {

				public void setBorder(Border border) {
				}

				@Override
				public void paint(Graphics g) {
					if (splitPane != null) {
						int[] xs = new int[3];
						int[] ys = new int[3];
						int blockSize;

						// Fill the background first ...   
						g.setColor(Color.WHITE);
						g.fillRect(0, 0, this.getWidth(), this.getHeight());

						// ... then draw the arrow.   
						if (orientation == JSplitPane.VERTICAL_SPLIT) {
							blockSize = Math.min(getHeight(), oneTouchSize);
							xs[0] = blockSize;
							xs[1] = blockSize << 1;
							xs[2] = 0;
							ys[0] = blockSize;
							ys[1] = ys[2] = 0;
						} else {
							blockSize = Math.min(getWidth(), oneTouchSize);
							xs[0] = xs[2] = 0;
							xs[1] = blockSize;
							ys[0] = 0;
							ys[1] = blockSize;
							ys[2] = blockSize << 1;
						}
						g.setColor(BG_COLOR);
						g.fillPolygon(xs, ys, 3);
					}
				}

				// Don't want the button to participate in focus traversable.   

				public boolean isFocusTraversable() {
					return false;
				}
			};
			b.setMinimumSize(new Dimension(oneTouchSize, oneTouchSize));
			b.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
			b.setFocusPainted(false);
			b.setBorderPainted(false);
			b.setRequestFocusEnabled(false);
			return b;
		}

		/**
		 * Creates and return an instance of JButton that can be used to collapse the left component in the split pane.
		 */
		protected JButton createLeftOneTouchButton() {
			@SuppressWarnings("serial")
			JButton b = new JButton() {

				public void setBorder(Border b) {
				}

				public void paint(Graphics g) {
					if (splitPane != null) {
						int[] xs = new int[3];
						int[] ys = new int[3];
						int blockSize;

						// Fill the background first ...   
						g.setColor(Color.WHITE);
						g.fillRect(0, 0, this.getWidth(), this.getHeight());

						// ... then draw the arrow.   
						g.setColor(BG_COLOR);
						if (orientation == JSplitPane.VERTICAL_SPLIT) {
							blockSize = Math.min(getHeight(), oneTouchSize);
							xs[0] = blockSize;
							xs[1] = 0;
							xs[2] = blockSize << 1;
							ys[0] = 0;
							ys[1] = ys[2] = blockSize;
							g.drawPolygon(xs, ys, 3); // Little trick to make the   
							// arrows of equal size   
						} else {
							blockSize = Math.min(getWidth(), oneTouchSize);
							xs[0] = xs[2] = blockSize;
							xs[1] = 0;
							ys[0] = 0;
							ys[1] = blockSize;
							ys[2] = blockSize << 1;
						}
						g.fillPolygon(xs, ys, 3);
					}
				}

				// Don't want the button to participate in focus traversable.   

				public boolean isFocusTraversable() {
					return false;
				}
			};
			b.setMinimumSize(new Dimension(oneTouchSize, oneTouchSize));
			b.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
			b.setFocusPainted(false);
			b.setBorderPainted(false);
			b.setRequestFocusEnabled(false);
			return b;
		}

		@Override
		public void paint(Graphics g) {
			super.paint(g);
			Dimension size = getSize();
			g.setColor(BG_COLOR);
			g.fillRect(1, 1, size.width - 1, size.height - 1);
			g.setColor(Color.GRAY);
			g.drawRect(0, 0, size.width, size.height);
			g.setColor(Color.WHITE);
			//分为水平时跟垂直时,白色区域   
			if (orientation == JSplitPane.VERTICAL_SPLIT) {
				g.fillRect(area_x, 1, 30, size.height - 1);
			} else {
				g.fillRect(1, area_y, size.width - 1, 30);
			}
			theL$UButton = leftButton;
			theR$DButton = rightButton;
			if (leftButton != null) {
				leftButton.repaint();
			}
			if (rightButton != null) {
				rightButton.repaint();
			}
		}

		/**
		 * Used to layout a <code>BasicSplitPaneDivider</code>. Layout for the divider involves appropriately moving the left/right buttons around.
		 * <p>
		 */
		protected class DividerLayout implements LayoutManager {

			public void layoutContainer(Container c) {
				if (leftButton != null && rightButton != null) {
					if (splitPane.isOneTouchExpandable()) {
						Insets insets = getInsets();

						if (orientation == JSplitPane.VERTICAL_SPLIT) {
							int extraX = (insets != null) ? insets.left : 0;
							int blockSize = getHeight();

							if (insets != null) {
								blockSize -= (insets.top + insets.bottom);
								blockSize = Math.max(blockSize, 0);
							}
							blockSize = Math.min(blockSize, oneTouchSize);

							int y = (c.getSize().height - blockSize) / 2;

							if (!centerOneTouchButtons) {
								y = (insets != null) ? insets.top : 0;
								extraX = 0;
							}
							int width = (int) MyBasicSplitPaneDivider.this.getSize().getWidth();
							area_x = width / 2 - oneTouchSize;
							leftButton.setBounds(extraX - oneTouchOffset + width / 2, y, blockSize * 2, blockSize);
							rightButton.setBounds(extraX - oneTouchOffset + oneTouchSize * 2 + width / 2, y, blockSize * 2, blockSize);
						} else {
							int extraY = (insets != null) ? insets.top : 0;
							int blockSize = getWidth();
							if (insets != null) {
								blockSize -= (insets.left + insets.right);
								blockSize = Math.max(blockSize, 0);
							}
							blockSize = Math.min(blockSize, oneTouchSize);

							int x = (c.getSize().width - blockSize) / 2;

							if (!centerOneTouchButtons) {
								x = (insets != null) ? insets.left : 0;
								extraY = 0;
							}
							int height = (int) MyBasicSplitPaneDivider.this.getSize().getHeight();
							area_y = height / 2 - oneTouchSize;
							leftButton.setBounds(x, extraY - oneTouchOffset + height / 2, blockSize, blockSize * 2);
							rightButton.setBounds(x, extraY - oneTouchOffset + oneTouchSize * 2 + height / 2, blockSize, blockSize * 2);
						}
					} else {
						leftButton.setBounds(-5, -5, 1, 1);
						rightButton.setBounds(-5, -5, 1, 1);
					}
				}
			}

			public Dimension minimumLayoutSize(Container c) {
				// NOTE: This isn't really used, refer to   
				// BasicSplitPaneDivider.getPreferredSize for the reason.   
				// I leave it in hopes of having this used at some point.   
				if (splitPane == null) {
					return new Dimension(0, 0);
				}
				Dimension buttonMinSize = null;

				if (splitPane.isOneTouchExpandable() && leftButton != null) {
					buttonMinSize = leftButton.getMinimumSize();
				}

				Insets insets = getInsets();
				int width = getDividerSize();
				int height = width;

				if (orientation == JSplitPane.VERTICAL_SPLIT) {
					if (buttonMinSize != null) {
						int size = buttonMinSize.height;
						if (insets != null) {
							size += insets.top + insets.bottom;
						}
						height = Math.max(height, size);
					}
					width = 1;
				} else {
					if (buttonMinSize != null) {
						int size = buttonMinSize.width;
						if (insets != null) {
							size += insets.left + insets.right;
						}
						width = Math.max(width, size);
					}
					height = 1;
				}
				return new Dimension(width, height);
			}

			public Dimension preferredLayoutSize(Container c) {
				return minimumLayoutSize(c);
			}

			public void removeLayoutComponent(Component c) {
			}

			public void addLayoutComponent(String string, Component c) {
			}
		} // End of class BasicSplitPaneDivider.DividerLayout   
	}
}