2014JAVA复习题.doc

一、选择题1. Java语言的各种分隔符中，非法的是（）A. 空白符B. 分号C. 逗号D. 问号2. 下列表达式中，非法的是（）Int a=5,b=6;double c=1.1,d=2.2;A. a+c+dB. （a+c）-C. C0)System.out.println(older than +); else if(d=0)System.out.println(same as +); else System.out.println(younger than +); public void print() System.out.println(The object of +this.getClass().getName()+:+name+,+age); /this.getClass().getName()返回对象所属类的名字 class Student2 extends Per String address;String department;public Student2(String na ,int ag,String ad,String de) /用super调用超类的构造方法address = ad;department = de; public void print() super.print(); System.out.println(The other information of student: +address+,+department); public class Yuedu public static void main(String args ) Person2 pe = /用name=Tom,age=20实例化对象pe；Student2 st = new Student2(John,19,336 West Street,Computer);pe.print();st.print();pe.olderoryounger(st); 答案1. /用构造函数为成员属性赋初值public Person2(String na,int ag)name=na; age=ag;/为d赋值 d=this.age-p.age; /用super调用超类的构造方法super(na,ag);/用name=Tom,age=20实例化对象pe；new Per(Tom,20);2. 在java程序根目录下，有一个包含英文的文本文件“file.txt”，读取这个文件中的英文单词，并将文件中所有字符都转变为小写，然后写回到原文件中。import java.io.*;public class E5 public static void main(String args) StringBuffer buf=new StringBuffer();File f= /新建一个File类的对象，指向要读写的文本文件。 ; if( )System.out.println(文件不存在); return;try FileReader red= /新建一个从文件中读数据的FileReader对象int c;while( /从流中读数据 ) buf.append(char)c); red.close(); String s=buf.toString().toLowerCase(); FileWriter wri= /新建一个向文件中写数据的对象 ; wri.write(s); wri.close(); System.out.println(finish!); catch (IOException e) 答案2.: new File(file.txt) : !f.exists(): new FileReader(f) : (c=red.read()!=-1: new FileWriter(f)3. 利用文件输入流把Exa.txt里的内容写到屏幕上。import java.io.*;public class Example10_4 public static void main(String args) int b; /创建一个长度为25的字节数组tom try /创建一个以Exa.txt为文件的File对象 /创建一个FileInputStream类的对象in while(b= )!=-1) /读文件中的内容保存到tom数组中 String s=new String (tom,0,b); System.out.print(s); in.close(); catch(IOException e) System.out.println(File read Error+e); 答案3. : byte tom=new byte25; :File f=new File(Exa.txt);:FileInputStream in=new FileInputStream(f); :in.read(tom,0,25)4. 实现一个求矩形周长和面积的程序，其中给出了父类和接口，要求完善程序，写出子类和接口实现类：Square，并要求打印结果为：结果： The Area of Square(3,4) is 12.0The Perimenter of Square(3,4) is 14.0（1空：10分，2空：5分，3空：5分，共20分）interface Shapesdouble getArea();double getPerimenter();class Fatherpublic int weight,height;public Father(int x,int y )weight=x;height=y;public class T public static void main(String args) Square sq=new Square(3,4);System.out.println(The Area of Square(3,4) is + ;System.out.println(The Perimenter of Square(3,4) is + );答案 public class Square extends Father implements Shapes-4分public Square (int x, int y)super(x,y);-2分public double getArea() return this.weight*this.height;-2分public double getPerimenter() return 2*(this.height+this.weight);-2分 sq.getArea() sq.getPerimenter()5. 实现显示C:java目录下所有文件的名称（1空：5分，2空：5分，共10分）import java.io.File;public class F public static void main(String args)String dirname = c:java;File f1= new File(dirname);if(f1.isDirectory()String s = ;for(int i = 0; is.length; i+)File f = new File(dirname+si);if( )System.out.println(si);elseSystem.out.println(dirname+ is not a directory.);答案 f1.list(); f.isFile()6. 功能描述：本程序点击按钮实现求两个操作数的加减乘除操作。（1空：5分，2空：5分，3空：10分，共20分）import java.awt.FlowLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import javax.swing.JButton;import javax.swing.JComboBox;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JTextField;public class GUI extends JFrame implements ActionListener JTextField tOprand1,tOprand2,result;JComboBox op;JButton compute;public GUI()tOprand1=new JTextField(,10);tOprand2=new JTextField(,10);result=new JTextField(,10);compute = new JButton(计算);op = new JComboBox();op.addItem(+);op.addItem(-);op.addItem(*);op.addItem(/); 设置布局管理器为流式布局 this.add(tOprand1);this.add(op);this.add(tOprand2);this.add(compute);this.add(result); 设置注册监听器 this.pack();this.setSize(500,300);this.setVisible(true); this.addWindowListener(new WindowAdapter()public void windowClosing(WindowEvent e) System.exit(0);); public void actionPerformed(ActionEvent e) public static void main(String args) GUI mainFrame = new GUI();答案 this.setLayout(new FlowLayout();compute.addActionListener(this);int operator = op.getSelectedIndex();-2分double ret;double op1 = Double.parseDouble(tOprand1.getText();double op2 = Double.parseDouble(tOprand2.getText();-2分if(operator=0)ret = op1 + op2;else if(operator=1)ret = op1 - op2;else if(operator=2)ret = op1 * op2;else ret = op1/op2;-4分result.setText(ret+);-2分7. 编写一个应用程序，实现如下界面，要求在文本框中输入有关信息，单击OK按钮，在下面的文本域中显示信息；单击Clear按钮，将文本框中的数据清除。（1空：5分，2空：5分，共10分）import java.awt.*;import java.awt.event.*;import javax.swing.*;public class InputDemo extends JFrame implements ActionListener JButton jbtn1 = new JButton(OK), jbtn2 = new JButton(Cancel); JTextArea jta =new JTextArea(); JScrollPane jsp = new JScrollPane(jta); JTextField jtf1 = new JTextField(20), jtf2 = new JTextField(20), jtf3 = new JTextField(20); JPanel jp = new JPanel(), jp1 = new JPanel(), jp2 = new JPanel(), jp3 = new JPanel(), jp4 = new JPanel(); public InputDemo() jp1.add(new JLabel(姓名);jp1.add(jtf1); jp2.add(new JLabel(性别);jp2.add(jtf2); jp3.add(new JLabel(年龄);jp3.add(jtf3); jp4.setLayout(new FlowLayout(FlowLayout.CENTER); jp4.add(jbtn1);jp4.add(jbtn2); jp.setLayout(new GridLayout(4,1); jp.add(jp1);jp.add(jp2);jp.add(jp3);jp.add(jp4); add(jp,BorderLayout.NORTH); add(jsp,BorderLayout.CENTER); setTitle(Input Demo); setSize(300,250); setVisible(true); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); public void actionPerformed(ActionEvent e) String s = ;if(e.getSource() = jbtn1 ) s = s+ jtf1.getText()+n; s = s+ jtf2.getText()+n; s = s+ jtf3.getText()+n; else if(e.getSource() = jbtn2) jtf1.setText(); jtf2.setText(); jtf3.setText(); jta.setText(); public static void main(String args) InputDemo id = new InputDemo(); 答案. jbtn1.addActionListener(this); jta.setText(s);三、阅读程序写结果1. public class Yuedu1 public static void main(String args) int x,i; System.out.println(x1=+add(3,7); System.out.println(x2=+add(3,add(7,2);static int add(int x,int y)return x+y;1. 结果：x1=10x2=122. class leve1String name=;int height,width;public leve1();public leve1(leve1 le)name=;height=le.height;width=le.width;public leve1(String na,int h,int w)name=na;height=h;width=w;public int higherthen(leve1 t)return this.height-t.height;public void print()System.out.println(class leve1:);System.out.println(Name=:+name+,Height=:+height+,Width=:+width);class leve2 extends leve1 int width; public leve2(); public leve2(leve1 le,int h,int w) super(le); height=h; width=w; public int widerthen() return width-super.width; public void print() System.out.println(class leve2:); System.out.println(Name=:+name+,Height=:+height+,Width=:+width); public class lev_expublic static void main(String args) leve1 le1=new leve1(Tower_1,50,20);leve2 le2=new leve2(le1,40,25);le1.print();le2.print();System.out.println(leve1 is +le1.higherthen(le2)+ highter then leve2.);System.out.println(leve2 is +le2.widerthen()+ wider then leve1.); 2. 结果：class leve1:Name=:Tower_1,Height=:50,Width=:20class leve2:Name=:Tower_1,Height=:40,Width=:25leve1 is 10 highter then leve2.leve2 is 5 wider then leve1.3. import java.io.*;public class NumberEcho public static void main(String args)tryBufferedReader buffin=new BufferedReader(new InputStreamReader(System.in);System.out.print(请输入整数串:);String str=buffin.readLine();int i = Integer.parseInt(str);System.out.println(运算结果是:+(i*i+i);System.out.println(运算结果是:+i*i+i);catch(IOException e)System.out.println(Input error!);（假定用键盘输入整数串3）3. 结果为：请输入整数串:3运算结果是:12运算结果是:934. public class Yuedu public static void main(String args) System.out.println(fun(4); static int fun(int n)int t;if(n=0)|n=1)t=3;elset=n*fun(n-1);return