java期末考试上机练习

1.产生n个30以内的随机数，统计并输出1,2,3，各数段的数的个数，并输出数中的最大数和最小数。packagecom.zhang;importjava.util.Random;importjava.util.Scanner;publicclassDemo1{publicstaticvoidmain(String[]args){Scannersc=newScanner(System.in);intn=0,number;intarr[]=newint[31];intmaxNum=0,minNum=0;System.out.println(请输入要产生的随机数的个数n:);n=sc.nextInt();for(inti=0;in;i++){Randomr=newRandom();intnum=r.nextInt(31);arr[num]++;if(i==0){maxNum=minNum=num;}if(i0){if(nummaxNum){maxNum=num;}if(numminNum){minNum=num;}}}for(inti=0;i31;i++){System.out.println(i+出现了+arr[i]+次);}System.out.println(产生的最大数是:+maxNum);System.out.println(产生的最小数是:+minNum);}}2定义一个接口，接口中有四个抽象方法：求面积方法、求周长方法、显示面积方法及显示周长方法。定义Circle类和Rectangle类分别实现接口，在主类中实现显示圆和矩形的面积和周长。packagecom.zhang;publicinterfaceTuxing{publicabstractvoidsetArea();publicabstractvoidsetGrith();publicabstractdoublegetArea();publicabstractdoublegetGrith();}packagecom.zhang;publicclassCricleimplementsTuxing{doubler,grith,area;//r表示半径.grith是周长,area是面积publicCricle(doubler){this.r=r;}@OverridepublicvoidsetArea(){//TODOAuto-generatedmethodstubarea=Math.PI*r*r;}@OverridepublicvoidsetGrith(){//TODOAuto-generatedmethodstubgrith=2*r*Math.PI;}@OverridepublicdoublegetArea(){//TODOAuto-generatedmethodstubreturnarea;}@OverridepublicdoublegetGrith(){//TODOAuto-generatedmethodstubreturngrith;}}packagecom.zhang;publicclassRectangleimplementsTuxing{doubleheight,width;doublegrith,area;publicRectangle(doubleheight,doublewidth){this.height=height;this.width=width;}@OverridepublicvoidsetArea(){//TODOAuto-generatedmethodstubarea=height*width;}@OverridepublicvoidsetGrith(){//TODOAuto-generatedmethodstubgrith=2*(height+width);}@OverridepublicdoublegetArea(){//TODOAuto-generatedmethodstubreturnarea;}@OverridepublicdoublegetGrith(){//TODOAuto-generatedmethodstubreturngrith;}}packagecom.zhang;publicclassCeShi{publicstaticvoidmain(String[]args){Criclecricle=newCricle(2);Rectanglerectangle=newRectangle(2,2);cricle.setArea();cricle.setGrith();rectangle.setArea();rectangle.setGrith();System.out.println(圆的面积是+cricle.getArea());System.out.println(圆的周长是+cricle.getGrith());System.out.println(矩形的面积是+rectangle.getArea());System.out.println(矩形的周长是+rectangle.getGrith());}}3用户在两个输入框中分别输入两个整数，单击“求积”按钮，在第三个输入框中显示两数中的积，单击“求和”按钮，在第四个输入框中显示两数的和。packagecom.zhang;importjava.awt.BorderLayout;importjava.awt.GridLayout;importjava.awt.event.ActionEvent;importjava.awt.event.ActionListener;importjavax.swing.JButton;importjavax.swing.JFrame;importjavax.swing.JLabel;importjavax.swing.JPanel;importjavax.swing.JTextField;publicclassDemo3extendsJFrame{JTextFieldtf1,tf2,tf3,tf4;publicDemo3(){//TODOAuto-generatedconstructorstubsuper();setTitle(简单的计算GUI);setSize(250,180);JPanelpanel=newJPanel(newGridLayout(0,2));JLabellabel1=newJLabel(第一个整数:);panel.add(label1);tf1=newJTextField();panel.add(tf1);JLabellabel2=newJLabel(第二个整数:);panel.add(label2);tf2=newJTextField();panel.add(tf2);JLabellabel3=newJLabel(积的结果:);panel.add(label3);tf3=newJTextField();panel.add(tf3);JLabellabel4=newJLabel(和的结果:);panel.add(label4);tf4=newJTextField();panel.add(tf4);getContentPane().add(panel,BorderLayout.NORTH);JPanelpanel2=newJPanel();JButtonbu1=newJButton(求积);bu1.addActionListener(newActionListener(){@OverridepublicvoidactionPerformed(ActionEvente){//TODOAuto-generatedmethodstubintji=Integer.parseInt(tf1.getText().trim())*Integer.parseInt(tf2.getText().trim());tf3.setText(ji+);}});panel2.add(bu1);JButtonbu2=newJButton(求和);bu2.addActionListener(newActionListener(){@OverridepublicvoidactionPerformed(ActionEvente){//TODOAuto-generatedmethodstubinthe=Integer.parseInt(tf1.getText().trim())+Integer.parseInt(tf2.getText().trim());tf4.setText(he+);}});panel2.add(bu2);getContentPane().add(panel2,BorderLayout.SOUTH);setVisible(true);}publicstaticvoidmain(String[]args){newDemo3();}}效果：4设计一个下拉式菜单和弹出式菜单，菜单标题为：设置窗体背景色。菜单中包含4个选项：红色、绿色、蓝色、退出，快捷键如下图所示，并在“蓝色”与“退出”选项间加一条分隔线。给菜单项注册事件监听器并完成相应的功能。packagecom.zhang;importjava.awt.Color;importjava.awt.event.ActionEvent;importjava.awt.event.ActionListener;importjava.awt.event.KeyEvent;importjava.awt.event.MouseAdapter;importjava.awt.event.MouseEvent;importjavax.swing.JFrame;importjavax.swing.JMenu;importjavax.swing.JMenuBar;importjavax.swing.JMenuItem;importjavax.swing.JPopupMenu;importjavax.swing.JTextArea;importjavax.swing.KeyStroke;publicclassDemo4extendsJFrameimplementsActionListener{JMenuBarmenubar;JMenumenu;JMenuItemItem1,Item2,Item3,Item4,Item5,Item6,Item7,Item8;JPopupMenupopmenu;JTextAreatextarea;publicDemo4(){//TODOAuto-generatedconstructorstubsuper();setTitle(菜单例子);setSize(300,200);menubar=newJMenuBar();setJMenuBar(menubar);menu=newJMenu(菜单);menubar.add(menu);Item1=newJMenuItem(红色);Item1.setMnemonic(KeyEvent.VK_R);Item1.setAccelerator(KeyStroke.getKeyStroke('R',2));//ctrl+r快捷键menu.add(Item1);Item2=newJMenuItem(绿色);Item2.setMnemonic(KeyEvent.VK_G);Item2.setAccelerator(KeyStroke.getKeyStroke('G',2));//ctrl+g快捷键menu.add(Item2);Item3=newJMenuItem(蓝色);Item3.setMnemonic(KeyEvent.VK_B);Item3.setAccelerator(KeyStroke.getKeyStroke('B',2));//ctrl+b快捷键menu.add(Item3);Item4=newJMenuItem(退出