不幸的是，天真的编码/解码Shape到 XML 使用XMLEncoder/Decoder经常毁掉所有重要信息Shape!
因此，为了做到这一点，仍然使用上面提到的类，我们序列化并恢复正确构造的 bean，这些 bean 表示从PathIterator.这些豆子是：
-
PathBean它存储了集合PathSegment形成 Java-2D 形状的对象Shape.
-
PathSegment它存储路径特定部分的详细信息（线段类型、缠绕规则和坐标）。
SerializeShapes GUI
用于演示存储和恢复形状的 GUI。
- Click the Ellipse (
Ellipse2D), Rectangle (Rectangle2D) or Face (Area) buttons a couple of times.
- 退出 GUI。这些形状将被序列化到磁盘。
- 重新启动图形用户界面。上次随机绘制的形状将从磁盘中恢复并重新出现在 GUI 中。
所选形状将填充为绿色，其他形状将填充为红色。
package serialize2d;
import java.awt.*;
import java.awt.event.*;
import java.awt.font.FontRenderContext;
import java.awt.geom.AffineTransform;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Random;
import java.util.Vector;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javax.swing.event.*;
/** A GUI to make it easy to add/remove shapes from a canvas.
It should persist the shapes between runs. */
public class SerializeShapes {
JPanel ui;
JPanel shapePanel;
Random rand;
JPanel shapeCanvas;
DefaultListModel<Shape> allShapesModel;
ListSelectionModel shapeSelectionModel;
RenderingHints renderingHints;
SerializeShapes() {
initUI();
}
public void initUI() {
if (ui != null) {
return;
}
renderingHints = new RenderingHints(RenderingHints.KEY_DITHERING,
RenderingHints.VALUE_DITHER_ENABLE);
renderingHints.put(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
renderingHints.put(RenderingHints.KEY_ALPHA_INTERPOLATION,
RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
renderingHints.put(RenderingHints.KEY_COLOR_RENDERING,
RenderingHints.VALUE_COLOR_RENDER_QUALITY);
renderingHints.put(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
renderingHints.put(RenderingHints.KEY_STROKE_CONTROL,
RenderingHints.VALUE_STROKE_NORMALIZE);
ui = new JPanel(new BorderLayout(4, 4));
ui.setBorder(new EmptyBorder(4, 4, 4, 4));
JPanel controls = new JPanel(new FlowLayout(FlowLayout.CENTER, 4, 4));
ui.add(controls, BorderLayout.PAGE_START);
shapeCanvas = new ShapeCanvas();
ui.add(shapeCanvas);
rand = new Random();
allShapesModel = new DefaultListModel<Shape>();
JList<Shape> allShapes = new JList<Shape>(allShapesModel);
allShapes.setCellRenderer(new ShapeListCellRenderer());
shapeSelectionModel = allShapes.getSelectionModel();
shapeSelectionModel.setSelectionMode(
ListSelectionModel.SINGLE_SELECTION);
ListSelectionListener shapesSelectionListener
= new ListSelectionListener() {
@Override
public void valueChanged(ListSelectionEvent e) {
shapeCanvas.repaint();
}
};
allShapes.addListSelectionListener(shapesSelectionListener);
JScrollPane shapesScroll = new JScrollPane(
allShapes,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER
);
// TODO fix this hack..
shapesScroll.getViewport().setPreferredSize(new Dimension(60, 200));
ui.add(shapesScroll, BorderLayout.LINE_START);
Action addEllipse = new AbstractAction("Ellipse") {
@Override
public void actionPerformed(ActionEvent e) {
int w = rand.nextInt(100) + 10;
int h = rand.nextInt(100) + 10;
int x = rand.nextInt(shapeCanvas.getWidth() - w);
int y = rand.nextInt(shapeCanvas.getHeight() - h);
Ellipse2D ellipse = new Ellipse2D.Double(x, y, w, h);
addShape(ellipse);
}
};
addEllipse.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_E);
Action addRectangle = new AbstractAction("Rectangle") {
@Override
public void actionPerformed(ActionEvent e) {
int w = rand.nextInt(100) + 10;
int h = rand.nextInt(100) + 10;
int x = rand.nextInt(shapeCanvas.getWidth() - w);
int y = rand.nextInt(shapeCanvas.getHeight() - h);
Rectangle2D rectangle = new Rectangle2D.Double(x, y, w, h);
addShape(rectangle);
}
};
addRectangle.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_R);
final int faceStart = 128513;
final int faceEnd = 128528;
final int diff = faceEnd - faceStart;
StringBuilder sb = new StringBuilder();
for (int count = faceStart; count <= faceEnd; count++) {
sb.append(Character.toChars(count));
}
final String s = sb.toString();
Vector<Font> compatibleFontList = new Vector<Font>();
GraphicsEnvironment ge
= GraphicsEnvironment.getLocalGraphicsEnvironment();
Font[] fonts = ge.getAllFonts();
for (Font font : fonts) {
if (font.canDisplayUpTo(s) < 0) {
compatibleFontList.add(font);
}
}
JComboBox fontChooser = new JComboBox(compatibleFontList);
ListCellRenderer fontRenderer = new DefaultListCellRenderer() {
@Override
public Component getListCellRendererComponent(
JList list, Object value, int index,
boolean isSelected, boolean cellHasFocus) {
Component c = super.getListCellRendererComponent(
list, value, index,
isSelected, cellHasFocus);
JLabel l = (JLabel) c;
Font font = (Font) value;
l.setText(font.getName());
return l;
}
};
fontChooser.setRenderer(fontRenderer);
final ComboBoxModel<Font> fontModel = fontChooser.getModel();
BufferedImage bi = new BufferedImage(1, 1, BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
final FontRenderContext fontRenderContext = g.getFontRenderContext();
Action addFace = new AbstractAction("Face") {
@Override
public void actionPerformed(ActionEvent e) {
int codepoint = faceStart + rand.nextInt(diff);
String text = new String(Character.toChars(codepoint));
Font font = (Font) fontModel.getSelectedItem();
Area area = new Area(
font.deriveFont(80f).
createGlyphVector(fontRenderContext, text).
getOutline());
Rectangle bounds = area.getBounds();
float x = rand.nextInt(
shapeCanvas.getWidth() - bounds.width) - bounds.x;
float y = rand.nextInt(
shapeCanvas.getHeight() - bounds.height) - bounds.y;
AffineTransform move = AffineTransform.
getTranslateInstance(x, y);
area.transform(move);
addShape(area);
}
};
addFace.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_F);
Action delete = new AbstractAction("Delete") {
@Override
public void actionPerformed(ActionEvent e) {
int idx = shapeSelectionModel.getMinSelectionIndex();
if (idx < 0) {
JOptionPane.showMessageDialog(
ui,
"Select a shape to delete",
"Select a Shape",
JOptionPane.ERROR_MESSAGE);
} else {
allShapesModel.removeElementAt(idx);
shapeCanvas.repaint();
}
}
};
delete.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_D);
controls.add(new JButton(addEllipse));
controls.add(new JButton(addRectangle));
controls.add(new JButton(addFace));
controls.add(fontChooser);
controls.add(new JButton(delete));
try {
ArrayList<Shape> shapes = deserializeShapes();
for (Shape shape : shapes) {
allShapesModel.addElement(shape);
}
} catch (Exception ex) {
System.err.println("If first launch, this is as expected!");
ex.printStackTrace();
}
}
private void addShape(Shape shape) {
allShapesModel.addElement(shape);
int size = allShapesModel.getSize() - 1;
shapeSelectionModel.addSelectionInterval(size, size);
}
class ShapeCanvas extends JPanel {
ShapeCanvas() {
setBackground(Color.WHITE);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHints(renderingHints);
Stroke stroke = new BasicStroke(1.5f);
g2.setStroke(stroke);
int idx = shapeSelectionModel.getMinSelectionIndex();
Shape selectedShape = null;
if (idx > -1) {
selectedShape = allShapesModel.get(idx);
}
Enumeration en = allShapesModel.elements();
while (en.hasMoreElements()) {
Shape shape = (Shape) en.nextElement();
if (shape.equals(selectedShape)) {
g2.setColor(new Color(0, 255, 0, 191));
} else {
g2.setColor(new Color(255, 0, 0, 191));
}
g2.fill(shape);
g2.setColor(new Color(0, 0, 0, 224));
g2.draw(shape);
}
}
@Override
public Dimension getPreferredSize() {
return new Dimension(500, 300);
}
}
public JComponent getUI() {
return ui;
}
public static void main(String[] args) {
Runnable r = new Runnable() {
@Override
public void run() {
SerializeShapes se = new SerializeShapes();
JFrame f = new JFrame("Serialize Shapes");
f.addWindowListener(new SerializeWindowListener(se));
f.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
f.setContentPane(se.getUI());
f.setResizable(false);
f.pack();
f.setLocationByPlatform(true);
f.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
public void serializeShapes() throws FileNotFoundException {
ArrayList<Shape> shapes
= new ArrayList<Shape>();
Enumeration en = allShapesModel.elements();
while (en.hasMoreElements()) {
Shape shape = (Shape) en.nextElement();
shapes.add(shape);
}
ShapeIO.serializeShapes(shapes, this.getClass());
try {
Desktop.getDesktop().open(
ShapeIO.getSerializeFile(this.getClass()));
} catch (Exception e) {
e.printStackTrace();
}
}
public ArrayList<Shape> deserializeShapes() throws FileNotFoundException {
return ShapeIO.deserializeShapes(this.getClass());
}
class ShapeListCellRenderer extends DefaultListCellRenderer {
@Override
public Component getListCellRendererComponent(
JList<? extends Object> list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
Component c = super.getListCellRendererComponent(list, value, index,
isSelected, cellHasFocus);
JLabel l = (JLabel) c;
Shape shape = (Shape) value;
ShapeIcon icon = new ShapeIcon(shape, 40);
l.setIcon(icon);
l.setText("");
return l;
}
}
class ShapeIcon implements Icon {
Shape shape;
int size;
ShapeIcon(Shape shape, int size) {
this.shape = shape;
this.size = size;
}
@Override
public void paintIcon(Component c, Graphics g, int x, int y) {
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHints(renderingHints);
Rectangle bounds = shape.getBounds();
int xOff = -bounds.x;
int yOff = -bounds.y;
double xRatio = (double) bounds.width / (double) size;
double yRatio = (double) bounds.height / (double) size;
double ratio = xRatio > yRatio ? xRatio : yRatio;
AffineTransform scale = AffineTransform.getScaleInstance(1 / ratio, 1 / ratio);
AffineTransform shift = AffineTransform.getTranslateInstance(xOff, yOff);
AffineTransform totalTransform = new AffineTransform();
totalTransform.concatenate(scale);
totalTransform.concatenate(shift);
Area b = new Area(shape).createTransformedArea(totalTransform);
bounds = b.getBounds();
g2.setColor(Color.BLACK);
g2.fill(b);
}
@Override
public int getIconWidth() {
return size;
}
@Override
public int getIconHeight() {
return size;
}
}
}
class SerializeWindowListener extends WindowAdapter {
SerializeShapes serializeShapes;
SerializeWindowListener(SerializeShapes serializeShapes) {
this.serializeShapes = serializeShapes;
}
@Override
public void windowClosing(WindowEvent e) {
try {
serializeShapes.serializeShapes();
} catch (FileNotFoundException ex) {
ex.printStackTrace();
System.exit(1);
}
System.exit(0);
}
}
ShapeIO
执行与 XML 之间的 I/O。
package serialize2d;
import java.awt.Shape;
import java.beans.*;
import java.io.*;
import java.util.ArrayList;
public class ShapeIO {
/** Save the list of shapes to the file system. */
public static void serializeShapes(
ArrayList<Shape> shapes, Class serializeClass)
throws FileNotFoundException {
File f = getSerializeFile(serializeClass);
XMLEncoder xmle = new XMLEncoder(new FileOutputStream(f));
ArrayList<PathBean> pathSegmentsCollection = new ArrayList<>();
for (Shape shape : shapes) {
ArrayList<PathSegment> pathSegments =
BeanConverter.getSegmentsFromShape(shape);
PathBean as = new PathBean(pathSegments);
pathSegmentsCollection.add(as);
}
xmle.writeObject(pathSegmentsCollection);
xmle.flush();
xmle.close();
}
/** Load the list of shapes from the file system. */
public static ArrayList<Shape> deserializeShapes(Class serializeClass)
throws FileNotFoundException {
File f = getSerializeFile(serializeClass);
XMLDecoder xmld = new XMLDecoder(new FileInputStream(f));
ArrayList<PathBean> pathSegmentsCollection
= (ArrayList<PathBean>) xmld.readObject();
ArrayList<Shape> shapes = new ArrayList<Shape>();
for (PathBean pathSegments : pathSegmentsCollection) {
shapes.add(BeanConverter.getShapeFromSegments(pathSegments));
}
return shapes;
}
/** Provide an unique, reproducible & readable/writable path for a class. */
public static File getSerializeFile(Class serializeClass) {
File f = new File(System.getProperty("user.home"));
String[] nameParts = serializeClass.getCanonicalName().split("\\.");
f = new File(f, "java");
for (String namePart : nameParts) {
f = new File(f, namePart);
}
f.mkdirs();
f = new File(f, nameParts[nameParts.length-1] + ".xml");
return f;
}
}
BeanConverter
获得一个PathIterator来自Shape并将其转换为可序列化的 bean。将 bean 转换回GeneralPath.
package serialize2d;
import java.awt.Shape;
import java.awt.geom.*;
import java.util.ArrayList;
/** Utility class to convert bean to/from a Shape. */
public class BeanConverter {
/** Convert a shape to a serializable bean. */
public static ArrayList<PathSegment> getSegmentsFromShape(Shape shape) {
ArrayList<PathSegment> shapeSegments = new ArrayList<PathSegment>();
for (
PathIterator pi = shape.getPathIterator(null);
!pi.isDone();
pi.next()) {
double[] coords = new double[6];
int pathSegmentType = pi.currentSegment(coords);
int windingRule = pi.getWindingRule();
PathSegment as = new PathSegment(
pathSegmentType, windingRule, coords);
shapeSegments.add(as);
}
return shapeSegments;
}
/** Convert a serializable bean to a shape. */
public static Shape getShapeFromSegments(PathBean shapeSegments) {
GeneralPath gp = new GeneralPath();
for (PathSegment shapeSegment : shapeSegments.getPathSegments()) {
double[] coords = shapeSegment.getCoords();
int pathSegmentType = shapeSegment.getPathSegmentType();
int windingRule = shapeSegment.getWindingRule();
gp.setWindingRule(windingRule);
if (pathSegmentType == PathIterator.SEG_MOVETO) {
gp.moveTo(coords[0], coords[1]);
} else if (pathSegmentType == PathIterator.SEG_LINETO) {
gp.lineTo(coords[0], coords[1]);
} else if (pathSegmentType == PathIterator.SEG_QUADTO) {
gp.quadTo(coords[0], coords[1], coords[2], coords[3]);
} else if (pathSegmentType == PathIterator.SEG_CUBICTO) {
gp.curveTo(
coords[0], coords[1], coords[2],
coords[3], coords[4], coords[5]);
} else if (pathSegmentType == PathIterator.SEG_CLOSE) {
gp.closePath();
} else {
System.err.println("Unexpected value! " + pathSegmentType);
}
}
return gp;
}
}
PathBean
将路径段的集合存储在可序列化 bean 中。
package serialize2d;
import java.awt.geom.*;
import java.util.ArrayList;
/** PathBean stores the collection of PathSegment objects
that constitute the path of a Shape. */
public class PathBean {
public ArrayList<PathSegment> pathSegments;
public PathBean() {}
public PathBean(ArrayList<PathSegment> pathSegments) {
this.pathSegments = pathSegments;
}
public ArrayList<PathSegment> getPathSegments() {
return pathSegments;
}
public void setPathSegments(ArrayList<PathSegment> pathSegments) {
this.pathSegments = pathSegments;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder("{");
for (PathSegment pathSegment : pathSegments) {
sb.append(" \n\t");
sb.append(pathSegment.toString());
}
sb.append(" \n");
sb.append("}");
return "PathSegments: " + sb.toString();
}
}
PathSegment
存储整个路径的一部分的路径段。
package serialize2d;
import java.util.Arrays;
/** PathSegment bean stores the detail on one segment of the path
that constitutes a Shape. */
public class PathSegment {
public int pathSegmentType;
public int windingRule;
public double[] coords;
public PathSegment() {}
public PathSegment(int pathSegmentType, int windingRule, double[] coords) {
this.pathSegmentType = pathSegmentType;
this.windingRule = windingRule;
this.coords = coords;
}
public int getPathSegmentType() {
return pathSegmentType;
}
public void setPathSegmentType(int pathSegmentType) {
this.pathSegmentType = pathSegmentType;
}
public int getWindingRule() {
return windingRule;
}
public void setWindingRule(int windingRule) {
this.windingRule = windingRule;
}
public double[] getCoords() {
return coords;
}
public void setCoords(double[] coords) {
this.coords = coords;
}
@Override
public String toString() {
String sC = (coords != null ? "" : Arrays.toString(coords));
String s = String.format(
"PathSegment: Path Segment Type:- %d \t"
+ "Winding Rule:- %d \tcoords:- %s",
getPathSegmentType(), getWindingRule(), sC);
return s;
}
}
Notes
这旨在作为概念证明，而不是完善的方法。
- XML 序列化数据变得非常快，通常会被压缩。 Zip 压缩可以使序列化对象或类文件的字节大小减少 30-40%，但可以使 XML 减少 80-95%。无论如何，zip 对于下一点也很有效。
- 对于我们希望提供的项目类型序列化和恢复形状，我们可能会also想要包含形状的更多细节（例如填充颜色或纹理以及绘制颜色或描边等）以及其他数据（如图像或字体）。这也是 Zip 派上用场的地方，因为我们可以将它们全部放在同一个存档中，每个存档都具有最佳压缩级别（例如 XML 标准，但图像没有标准）。
A 本答案中源文件的 zip 存档 https://drive.google.com/drive/#folders/0B5B9wDXIGw9lUnJaUjA2cmlVRE0可以从我的云盘下载。
