全国计算机等级考试二级Java语言程序设计上机操作(三)

1、一、基本操作题本题的功能是统计成绩不及格的人数,分数有89,90, 56,90,89,45。23,45,60, 59,61。public class javalpublic static void main(Stringargs(int 3score=56。90。89,23,45,61,60,59;int hum=0;int i=0:while( if( sum+:i+;第1处:int sum=0第2处:i第3处:scorei<60或scorei<=59【解析】第1处是定义变量,前面的int num=0只是迷惑考生的;第2处为循环条件;第3处判断是否及格。二、简单应用题本题中,窗口

2、的背景色为系统桌面的颜色,在窗口中分别画空心和实心的黑色矩形、深灰色圆角矩形和浅灰色椭圆形,并且画白色粗体的“欢迎学习Java!”字符串。public class java2public static void main(StringargsFillFrame frame=new FillFrame(;frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE;frame.show(;class FillFrame extends JFramepublic FillFrame(setTitle("java2":setSize(WI

3、DTH,HEIGHT;FillPanel panel=new FillPanel(;panel.setBackground(SystemColor.desktop;Container contentPane=getContentPane(;contentPane.add(panel;public static final int WIDTH=400;public static final int HEIGHT=250;class FitlPanel extends JPanelpublic void paintComponent(Graphics g;g.setColor(new Color(

4、10,10,10;g.drawRect(10,10,100,30;g.setColor(new Color(100,100,lOO;g.drawRoundRect(150,10,100,30,15,15;g.setColor(new Color(150,150,150;g.drawOval(280,10,80,30;g.setColor(new Color(10,10,10;g.fillRect(10,ll0,100,30;g.setColor(new Color(100,100,100;g.fillRoundRect(150,110,100,30,15,15;g.setColor(new C

5、olor(150,150,150;g.fillOval(280,110,80,30;g.setColor(Color.white;Font f=new Font("宋体”,20;g.setFont(f;g.drawstring("欢迎学习Java!",l50,200;第1处:super.paintComponent(g第2处:Font.Bold【解析】第1处使用父类方法应使用super来引用;第2处为设置粗体。三、综合应用题本题的功能是对图形进行操作,包括旋转、移位、放大和剪切。窗口中有4个单选按钮和一个图形面板,图形面板中有一个矩形和该矩形移位操作后的图形,任选

6、其中一个单选按钮,则图形面板中将显示该操作后的图形。public class java3public static void main(StringargsJFrame frame=new TransformTestFrame(;frame.setDefaultCloseOperation(JFrame.EXIT_0N_CLoSE;frame.show(;class TransformTest extends JFramepublic TransformTestFrame(setTitle("java3"setSize(WIDTH,HEIGHT;Container cont

7、entPane=getContentPane(;canvas=new TransformPanel(;contentPane.add(canvas,BorderLayout.CEN-TER;JPanel buttonPanel=new JPanel(:ButtonGroup group=new ButtonGroup(;JRadioButton rotateButton=new JRadioButton("旋转",true;buttonPanel.add(rotateButton;group.add(rotateButton;rotateButton.addActionLi

8、stener(newActionListener(public void actionPerformed(ActionEvent eventcanvas.setRotate(;JRadioButton trans|ateButton=new JRadioButton("移位",false;buttonPanel.add(translateButton;group.add(translateButton;translateButton.addActionListener(new ActionLiatener(public void actionPerformed(Action

9、Event event canvas.setTranslate(;JRadioButton scaleButton=new JRadioButton("放大",false;buttonPanel.add(scaleButton:group.add(scaleButton;scaleButton.addActionListener(new ActionListener(public void actionPerformed(ActionEvent event canvas.setScale(;JRadioButton shearButton=new JRadioButton(

10、"剪切",false;buttonPanel.add(shearButton:group.add(shearButton;shearButton.addActionListener(new ActionListener(public void actionPerformed(ActionEvent event canvas.setShear(;contentPane.add(buttonPanel,BorderLayout. NORTH:private TransformPanel canvas;private static final int WIDTH=300;priv

11、ate static final int HEIGHT=300;class TransformPanel extend JPanelpublic TransformPanel(square=new Rectangle2D.Double(-50,-50,100,100;t = new AffineTransform(;setRotate(;public void paintComponent(super.paintComponent(g;Graphics2D g2=(Graphies2Dg;g2.translate(getWidth(/2,getHeight(/2:g2.setPaint(Col

12、or.gray;g2.draw(square;g2.transform(t;g2.setPaint(Color.black;g2.draw(square;public void setRotate(t.setToRotation(Math.toRadians(30;repaint(;public void setTranslate(t.setToTranslation(20,1 5;repaint(;public void setScale(t.setToScale(2.0,1.5:repaint(;public void setShear(t.setToShear(-0.2,O;repaint(;private Rectangle2D square;private AffineTransform t;第1处:class Tran