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 javal{
public static void main(String[]args)(
int 3score={56。90。89,23,45,61,60,59};
int hum=0;
;
int i=0:
while(){
if()
sum++:
i++;
}
System.out.println(”<60:”+sum);
}
}
第1题
javal
partl part2,则打印输出为:partl part2。
public class javal{
public static void main(String[]args){
int i=0:
while( ){
System.OUt.print( +"");
;
}
System.out.println();
}
}
第2题
本题中,在下画线上填写代码,指定变量b为字节型,变量f为单精度实型,变量l为64位整型。
public class javal{
public static void main(String[-]args){
b=49;
f=8.9f;
l=0xfedl;
System.out.println("b="+b);
System.out.println("f="+f):
System.OUt.println("l="+1);
}
}
第3题
粘贴”,在颜色设置框中设置颜色后,下面的预览面板将显示选中的颜色,单击“复制”按钮后,将设置的颜色复制到系统的剪贴板上,然后继续选择其他颜色,当单击按钮“粘贴”后预览面板的颜色将设置为刚才复制的颜色。
importjava.io.*;
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
public class java3
{
public static void main(String[]args)
{
JFrame. frame=new SerialTransferFrame():
frame.setDefaultCloseoperation(JFrame.EXIT
ON_CLOSE);
frame.show();
}
}
class SerialTransferFrame. extends JFrame
{
public SerialTransferFrame()
{
setTitle("java3"):
Container contentPane = getContentPane();
chooser=new JColorChooser();
contentPane.add(chooser,BorderLayout.CEN-
TER);
JPanel panel=new JPanel();
JButton copyButton=new JButton("复制");
panel.add(copyButton);
copyButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
copy();
}
});
JButton pasteButton=new JButton("粘贴");
panel.add(pasteButton);
pasteButton.addAetionListener(new
ActionListener()
{
public void aetionPerformed(AetionEvent event)
{
paste();
}
});
contentPane.add(panel,BorderLayout.SOUTH);
pack();
}
private void copy()
{
Clipboard clipboard
=Toolkit.getDefaultToolkit().getSystemClip-
board();
int color=chooser.getColor();
SerialSeleetion selection=new SerialSelection
(color);
clipboard.setContents(selection,null);
}
private void paste()
{
Clipboard clipboard
=Toolkit.getDefaultToolkit().getSystemClip-
board();
Transferable contents=clipboard.getContents
(null);
if(contents= =null)return;
try
{
DataFlavor flavor=new DataFlavor(
"application/x-java-serialized-object;class=
java.awt.Color");
if(contents.isDataFlavorSupported(flavor))
{
Color color
=(Color)contents.getTransferData(flavor);
;
}
}
catch(ClassNotFoundException exception)
{
JOptionPane.showMessageDialog(this,excep-
tion);
}
catch(UnsupportedFlavorException exception)
{
JOptionPane.showMessageDialog(this,excep-
tion);
}
catch(IOException exception)
{
JOptionPane.showMessageDialog(this,excep-
tion);
}
}
private JColorChooser chooser;
}
class SerialSelection implements Transferable
{
SerialSelection(Serializable o)
{
obj=o:
}
public DataFlavor[]getTransferDataFlavors()
{
DataFlavor[]flavors=new DataFlavor[2];
Class type=obj.getClass();
String mimeType
="application/x-java-serialized-object;class
="
+type.getName();
try
{
flavors[0]=new DataFlavor(mimeType);
flavors[1]=DataFlavor.stringFlavor;
return flavors;
}
catch(ClassNotFoundExeeption exception)
{
return new DataFlavor[O];
}
}
public boolean isDataFlavorSupported(DataFlavor
flavor)
{
Return
DataFlavor.stringFlavor.equals(flavor)‖"appli-
cation".equals(flavor.getPrimaryType())
&;&;"x-iava-serialized-object".equals(flavor.
getSubType())
&;&;flavor.getRepresentationClass().isAssign-
ableFrom(obj.getClass());
}
public void getTransferData(DataFlavor flavor)
throws UnsupportedFlavorException
{
if(! isDataFlavorSupported(flavor))
throw new UnsupportedFlavorException(flaVor);
if(DataFlavor.stringFlavor.equals(flavor))
return obj.toString();
return obj;
}
private Serializable obj;
}
第4题
交叉的图形,选中其中一个单选按钮,图形面板中以黑色填充的方式显示运算结果。
import java.awt.*;
import java.awt.event*+;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;
public class java3
{
public static void main(String[]args)
{
JFrame. frame=new AreaTestFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_
ON_CLOSE);
frame.show();
}
}
class AreaTestFrame. extends JFrame
{
public AreaTestFrame()
{
setTitle("java3");
setSize(WIDTH,HEIGHT);
areal
=new Area(new Ellipse2D.Double(100,100,
150,100));
area2
=new Area(new Rectangle2D.Double(150,150,
150,100));
Container confentPane=getContentpane();
panel=new
JPanel()
{
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2=(Graphics2D)g;
g2.draw(areal);
g2.draw(area2);
if(area!=null)g2.fill(area);
}
};
contentPane. add(panel,BorderLayout. CEN-
TER);
JPanel buttonPanel=new JPanel();
ButtonGroup group=new ButtonGroup();
JRadioButton addButton=new JRadioButton("
并",false);
buttonPanel.add(addButton);
group.add(addButton);
addButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
area=new Area();
area.add(areal);
area.add(area2);
panel.repaint();
}
});
JRadioButton subtractButton
=new JRadioButton("减",false);
buttonPanel.add(subtractButton);
group.add(subtractButton);
subtractButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
area=new Area();
area.add(areal);
area.subTract(area2);
panel.repaint();
}
});
JRadioButton intersectButton
=new JRadioButton("交",false);
buttonPanel.add(intersectButton);
group.add(intersectButton);
intersectButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
area=new Area():
area.add(areal);
area.intersect(area2);
panel.repaint();
}
});
JRadioButton exclusiveCIrButton
=new JRadioButton(“异或”,false);
buttonPanel.add(exelusiveOrButton);
group.add(exclusiveOrButton);
exclusiveOrButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
area=new Area();
area.add(areal);
area.exclusiveor(area2);
panel.repaint();
}
});
contentPane.add(buttonPanel,BorderLayout.
NORTH);
}
private JPanel panel;
private Area area;
private Area areal;
private Area area2;
private static final int WIDTH=400;
private static final int HEIGHT=400;
}
第5题
选中该复选按钮后,鼠标置于窗口上,单击鼠标右键会弹出一个菜单,单击菜单项中的选项后,后台会输出单击的菜单项,如果取消该复选按钮的选择,单击鼠标右键则不能弹出菜单。
import java.awt.*;
import java.awt.event.*;
class CanvasWithPopup extends Canvas{
Popupmenu popup;
CanvasWithPopup(PopupMenu popup){
enableEvents(AWTEvent.MOUSE EVENT
MASK):
this.popup=popup;
}
void addPopup(){
add(popup);
}
void removePopup(){
remove(popup);
}
protected void processMouseEvent(MouseEvent
evt){
if(popup.getParent()!=null&;&;evt.isPop-
upTrigger()){
popup.show(evt.getComponent(),evt.getX(),
evt.getY());
}
super.processMouseEvent(evt);
}
}
public class java3 extends Frame. implements Item-
Listener,ActionListener{
Checkbox cb=new Checkbox("弹出菜单",
false);
CanvasWithPopup canvas;
java3(){
super("java3");
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
add(cb,BorderLayout.NORTH);
cb.addhemListener(this);
PopupMenu popup=new PopupMenu("Button
Control"):
popup.add("iteml");
popup.add("item2");
popup.addActionListener(this);
canvas=new CanvasWithPopup(popup);
add(canvas,BorderLayout.CENTER);
setSize(100,200);
show();
}
第6题
”按钮,则会在当前所选列表项后添加一个名为“新增表项”的列表项,同时后台输入列表中的表项数量。单击“删除”按钮后,如果未选中表项,则弹出提示消息框“请选择表项”。否则将选中的表项删除,同时后台输出删除表项的内容和列表中的表项数量。单击“关闭”按钮退出程序。
import java.awt.*;
import java.awt.event.*;
import javax.swing.JOptionPane;
public class java3
{
public static void main(String args[])
{
final Frame. frmFrame=new Frame();
Panel pnlPanell=new Panel();
Panel pnlPanel2=new Panel();
final List lstList=new List(8):
for(int i=0;i<;10;i++)
{
String strName="表项"+(new Integer(i+
1)).toString():
lstList.add(strName);
}
Button btnButtonl=new Button("添加");
Button btnButton2=new Button("删除");
Button btnButton3=new Button("关闭");
btnButtonl.addActionListener(new AetionListen-
er()
{
public void actionPerformed(ActionEvent e)
{
lstList.add("新增表项",lstList.getSelected()+
1);
System.out.println("列表中的表项数量:"+
lstList.getItemCount());
}
});
btnButton2.addActionListener(new ActionListen-
er()
{
public void aetionPerformed(ActionEvent e)
{
if(lstList.getSelected()= =null)
{
JOptionPane.showMessageDialog(frmFrame,"请
选择表项");
return;
}
System.out.println("删除表项的内容:"+
IstList.getSelectedItem());
lstList.delete(lstList,getSelectedIndex());
System.out.println("列表中的表项数量:"+
lstList.getltemCount()):
}
});
btnButton3.addActionListener(new ActionListen-
er()
{
public void actionPerformed(ActionEvent e)
{
System.exit(O);
}
});
pnlPanell.add(lstList);
pnlPanel2.add(btnButtonl);
pnlPanel2.add(btnButton2);
pnlPanel2.add(btnButton3);
frmFrame.add("North",pnlPanell);
frmFrame.add("South",pnlPanel2);
frmFrame.setTitle("java3");
frmFrame.pack();
frmFrame.show();
}
}
第7题
击按钮时图形按钮的图形又发生改变,当鼠标左键松开或者移开鼠标后,图形按钮的图形又恢复原样。
import javax.swing.*;
import java.awt.*;
public class java3 extend Jbutton{
public java3(Icon icon,Icon pressed,Icon rollover){
this(icon);
setFocusPainted(false);
setRolloverEnabled(true);
setRolloverlcon(rollover);
setPressedIcon(pressed);
setBorderPainted(false);
setContentAreaFilled(false);
}
public static void main(String[]args){
java3 b1=new java3(
new ImageIcon("java3-redcube.gif"),
new ImageIcon("java3-redpaw.gif"),
new ImageIcon("java3-reddiamond.gif"));
java3 b2一new java3(
new ImageIcon("java3-bluecube.gif")。
new ImageIcon("java3-bluepaw.gif"),
new ImageIcon("java3-bluediamond.gif"));
JFrame. f=new JFrame();
f.setTitle("java3");
f.setDefauhCloseOperation(JFrame.EXIT_ON_
CLOSE);
c=f.getContentpane();
c.setLayout(new FlowLayout());
c.add(b1);
c.add(b2);
f.pack();
f.setVisible(true);
第8题
话框上有两个按钮“Yes"和“N0”,单击对话框上的“Yes”和“N0”按 钮后返回主窗口,并在右侧文本域中显示刚才所单击的按钮信息。
import java.awt.event.*;
import java.awt.*;
class MyDialog implements ActionListener
{static final int YES=1,N0=0;
int message=-1;Button yes,no;
MyDialog(Frame. f.String S,boolean b)
{super(f,S,b);
ves=new Button("Yes");yes.addActionListener
(this);
no=new Button("No"); no.addActionListener
(this)o
setLayout(new FlowLayout());
add(yes);add(no);
setBounds(60,60,100,100);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{message=-1;setVisible(false);)
});
}
public void actionPerformed(ActionEvent e)
{if(e.getSource()= =yes)
{message=YES;
setVisible(false);
}
else if(e.getSource()= = no)
{message=NO;
setVisible(false);
}
}
public int getMessage()
{return message;
}
}
class Dwindow extends Frame. implements ActionLis-
tener
{TextArea text;Button button;MyDialog dialog;
Dwindow(String s)
{super(s);
text=new TextArea(5,22);button=new Button
("打开对话框");
button.addActionListener(this);
setLayout(new FlowLayout());
add(button);add(text);
dialog=new MyDialog(this,"Dialog",true);
setBounds(60,60,300,300);setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{System.exit(0);}
});
}
public void actionPerformed(ActionEvent e)
{if(e.getSource()= =button)
{
if(dialog.getMessage()= =MyDialog.YES)
{text.append("\n你单击了对话框的yes按
钮");
}
else if(dialog.getMessage()= =MyDialog.NO)
{text.append("\n你单击了对话框的N0按
钮");
}
}
}
}
public class java2
{public static void main(String args[])
{new Dwindow("java2");
}
}
第9题
本题中定义了一个树型的通信录,窗El左侧是一个树,
右侧是一个文本域,单击树的结点,则在右侧文本域中显示
相关信息,如果单击的是树结点,则显示对应名字的电话
信息。
import javax.swing.*;
import javax.swing.tree.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
class Mytree2 extends JFrame
{JTree tree=null;JTextArea text=new JTextArea
(20,20);
Mytree2()
{Container con=getContentPane();
DefauhMutableTreeNode root=new Default-
MutableTreeNode("同学通信录");
DefaultMutableTreeNode tl=new Default-
MutableTreeNode("大学同学");
DefaultMutableTreeNode t2=new Default-
MutableTreeNode("研究生同学");
DefaultMutableTreeNode tl l=new Default-
MutatleTreeNode("陈艳");
DefaultMutableTreeNode tl 2=new Default-
MutableTreeNode("李小永");
DefaultMutableTreeNode t2 1=new Defauh-
MutableTreeNode("王小小");
DefauhMutableTreeNode t2 2=new Defauh-
MutableTreeNode("董小");
setTitle("java2");
root.add(t1);root.add(t2);
tl.add(t1_1);tl.add(t1_2);t2.add(t2_1);t2.
add(t2_2);
tree=new JTree(root);
JSerollPane scrollpane=new JScrollPane(text);
JSplitPane splitpane=new JSplitPane(JSplitPane.
HORIZONTAL SPLIT,
true,tree,scrollpane);
tree.addTreeSeleetionListener(this);
con.add(splitpane);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{System.exit(0);}});
setVisible(true);setBounds(70,80,200,300);
}
public void valueChanged(TreeSelectionEvent e)
{if(e.getSouree()= =tree)
{DefauhMutableTreeNode node=
(DefaultMutableTreeNode)tree.getLastSelected-
PathComponent();
if(node.isLeaf())
(String str= ;
if(str.equals("陈艳"))
(text.setText(str+":联系电话:0411-
4209876");}
else if(str.equals("李小永"))
{text.setText(str+":联系电话:010-
62789876");}
else if(str.equals("王小小"))
{text.setText(str+":联系电话:0430-
63596677");)
else if(str.equals("董小"))
{text.setText(str+":联系电话:020-
85192789");}
}
else
{text.setText(node.getUserObject().toString
());
}
}
}
}
public class java2
{public static void main(String args[])
{Mytree2 win=new Mytree2();win.pack();}
}
第10题
本题是一个Applet,它的功能是在窗口上添加12×12个标签,并且横向和纵向标签的颜色为黑白相间。
import java.applet.*;
import java..awt.*;
import java,.awt.event*;
pubhc class java2
extends Applet
{GridLayout grid;
pubhc void init()
{grid=new GridLayout(12,12);
setLayout(grid);
Label =new Label[12][12];
for(int i=0;i<;12;i++)
{for(int j=0;j<;12;j++)
{label[i][j]= ;
if((i+j)%2= =0)
label[i][j].setBackground(Color.black);
else
label[i][j].setBackground(color.white);
add(label[i][j]);
}
}
}}
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