发学生第7次JAVA测试题第10章输入输出流内容20101211
java 输入输出流实验

}
catch(Exception exp){}
clip.start();
voiceWord.setEnabled(true);
}
}6.实验指导
(1)BufferedReader对象调用readLine方法可读取文件中的一行内容。
catch(IOException exp){}
}
}
public void run()
{
voiceWord.setEnabled(false);
try{
if(clip!=null)
{
clip.close();
}
clip=AudioSystem.getClip();
File voiceFile=new File(showWord.getText().trim()+".wav");
add(pCenter,BorderLayout.CENTER);
menubar=new JMenuBar();
menu=new JMenu("帮助");
help=new JMenuIter("关于学单词");
help.addActionListener(this);
menu.add(help);
menubar.add(menu);
FileReader类是Reader的子类,该类创建的对象称为文件字符输入流。文件字符输入流按字符读取文件中的数据。FileReader流按顺序读取文件,只要不关闭流,每次调用读取方法时FileReader流就会依次读取文件中其余的内容,直到文件的末尾或流被关闭。
java输入输出流试验

输入输出流一、实验目的:熟悉Java的文件读写机制,练习输入输出流的使用。
二、实验内容:1、键盘输入10个整数,从小到大进行排序。
2、接收键盘输入的字符串,用FileInputStream类将字符串写入文件,用FileOutputStream类读出文件内容显示在屏幕上。
3、将一个文本文件的内容按行读出,每读出一行就顺序加上行号,并写入到另一个文件中。
三、实验要求:1. 通过实验掌握文件输入输出流的使用方法;2. 程序必须能够从键盘接收字符串并保存在文件中;3. 程序必须能够读出文件内容显示在屏幕上;4. 写出实验报告。
四、实验步骤:1、键盘输入10个整数,从小到大进行排序。
package javaTest;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;public class Gui_21 {public static void main(String[] args) throws IOException {// TODO Auto-generated method stubBufferedReader br=new BufferedReader(newInputStreamReader(System.in));String str;int array[]=new int[10];for(int i=0;i<10;i++){System.out.println("请输入一个整数:");str=br.readLine();array[i]=Integer.parseInt(str);}for(int j=0;j<9;j++){for(int k=j+1;k<10;k++){if(array[k]<array[j]){int temp=array[k];array[k]=array[j];array[j]=temp;}}}for(int m=0;m<10;m++){if(m!=9)System.out.print(array[m]+",");elseSystem.out.print(array[m]);}}}2、接收键盘输入的字符串,用FileInputStream类将字符串写入文件,用FileOutputStream类读出文件内容显示在屏幕上。
Java面向对象程序设计(第二版)第10章_Java的输入与输出流解读

目的 地
注意,流是有方向性的,输入流只能从中读取数据,而不能往一个输入流 中写数据。同样的,也不能从一个输出流中读数据。
10.3标准输入/输出流
System类管理标准输入/输出流和错误流。它提供了标 准输入流Syetem.in,标准输出流System.out,以及错误 流System.err。通过System类的基本属性in,可以获得 一个InputStream对象,其语句为: InputStream is=System.in; 它是一个标准输入流,一般接收键盘的响应,得到键盘 所传递来的数据。 System.out 是标准输出流,一般用于向显示设备(一般 是显示器)输出数据。它是Java.io包中PrintStream类的 一个对象,其println()、print()和write()方法用于输出数 据。 和System.out一样,System.err也是一个PrintStream对 象,用于向显示设备输出错误信息。
10.3标准输入/输出流(续)
例10.2从键盘读入若干字符,然后转换为字符串并在显示器上显示出来。 //Jpro10_2.java import java.io.*; public class Jpro10_2 { public static void main(String[] args) { InputStream is = System.in; try { byte[] bs = new byte[512]; int len = is.read(bs); String str=new String(bs); System.out.println("输入的内容:" +str); is.close(); } catch (IOException e){ e.printStackTrace(); } } }
java语言程序设计基础篇编程练习题7~10章

java语言程序设计基础篇编程练习题7~10章//7.2/*import javax.swing.*;class Fan{final static int SLOW=1;final static int MEDIUM=2;final static int FAST=3;private int speed;private boolean on;private double radius;private String color;Fan(){speed=SLOW;on=false;radius=5;color="blue";};void get(){System.out.println(speed+" "+on+" "+radius+" "+color);}void set(){char c;String s=JOptionPane.showInputDialog("请输入风扇的状态Y(开) N(关)");c=s.charAt(0);if(c=='Y'||c=='y'){on=true;System.out.println(on);}s=JOptionPane.showInputDialog("请输入风扇的速度(1,2,3)");speed=Integer.parseInt(s);s=JOptionPane.showInputDialog("请输入风扇半径");radius=Double.parseDouble(s);s=JOptionPane.showInputDialog("请输入风扇颜色");color=s;}public String toString(){if(on==true){String s="状态 "+on+" 半径 "+radius+" 风速 "+speed+" 颜色"+color;return s;}else{String s="fan is off";return s;}}}public class LQ{public static void main(String []args){Fan f1 = new Fan();Fan f2 = new Fan();f1.get();f1.set();System.out.println(f1.toString());f2.get();f2.set();System.out.println(f2.toString());}}*///7.4/*import javax.swing.*;class Stock{private String symbol;private String name;private double previousClosingPrice;private double currentPrice;Stock(String symbol,String name){this.symbol=symbol;/doc/3d11885499.html,=name;previousClosingPrice=4.5;currentPrice=5.0;}void front(){doublepreviousClosingPrice=Double.parseDouble(JOptionPane.showIn putDialog("请输入前一天股票价格"));this.previousClosingPrice=previousClosingPrice;void current(){doublecurrentPrice=Double.parseDouble(JOptionPane.showInputDialo g("请输入当前股票价格"));this.currentPrice=currentPrice;}double changePercent(){return previousClosingPrice/currentPrice;}}public class LQ{public static void main(String []args){Stock s=new Stock("20135","兴华");JOptionPane.showMessageDialog(null,s.changePercent());s.front();s.current();JOptionPane.showMessageDialog(null,s.changePercent());}}*///7.5/*import java.util.*;public class LQ{public static void main(String []args){GregorianCalendar g=new GregorianCalendar();JOptionPane.showMessageDialog(null,g.YEAR+":"+g.MONT H+":"+g.DAY_OF_MONTH);}}*///7.7/*class Time{private int hour;private int minute;private int second;Time(){Calendar c=Calendar.getInstance();hour=c.get(c.HOUR); minute=c.get(c.MINUTE); second=c.get(c.SECOND); }Time(long m){long ts=m/1000; second=(int)(ts%60); long tm=ts/60;minute=(int)(tm%60); long th=tm/60;hour=(int)(th%24);}int get1(){return hour;}int get2(){return minute;}intget3(){return second;}}public class LQ{public static void main(String []args){Time t1=new Time();JOptionPane.showMessageDialog(null,t1.get1()+" : "+t1.get2()+" : "+t1.get3());Time t2=new Time(System.currentTimeMillis());JOptionPane.showMessageDialog(null,t2.get1()+" : "+t2.get2()+" : "+t2.get3());}}*///7.8/*class Course{private String name;private String[] students=new String[100];private int numberOfStudents;public Course(String name){/doc/3d11885499.html,=name;}public void addStudent(String student){students[numberOfStudents]=student;numberOfStudents++;if(numberOfStudents==(students.length-1)) {String s[]=new String[students.length*2]; for(int i=0;i<students.length;i++){s[i]=students[i];}students=s;}}public String[] getStudents(){return students;}public int getNumberOfStudents(){return numberOfStudents;}public String getName(){return name;}}*///7.11/*class MyPoint{private double x;private double y;MyPoint(){x=0;y=0;}MyPoint(double x,double y){this.x=x;this.y=y;}double get1(){return x;}double get2(){return y;}double distance(double X,double Y) {return Math.sqrt((x-X)*(x-X)+(y-Y)*(y-Y)); }double distance(MyPoint M){return Math.sqrt((x-M.get1())*(x-M.get1())+(y-M.get2())*(y-M.get2()));}}public class LQ{public static void main(String []args){MyPoint M1=new MyPoint(0,0);MyPoint M2=new MyPoint(10,30.5);double d=M1.distance(M2);JOptionPane.showMessageDialog(null,d);}}*///7.12/*class StackOfIntegers{private int []s=new int [100];private int num=0;private int a;StackOfIntegers(int a)this.a=a;}void stor(){int j=2;int n,c;for(;a>2;){if(a%j==0){c=0;for(n=2;n<j;n++){if(j==2){c=0;}else if(j%n==0){c=1;break;} }if(c==0){s[num++]=j;a=a/j;j=2;}else{j++;}}else{j++;}}for(int i=num-1;i>=0;i--) {System.out.print(s[i]+" ");}}public class LQ{public static void main(String []args){StackOfIntegers S=new StackOfIntegers(120);S.stor();}}*///8.1/*public class LQ{public static void main(String []args){String s=JOptionPane.showInputDialog("请输入一串字符"); String s1=reverse(s);if(s1.equals(s)){JOptionPane.showMessageDialog(null,s+"是回文串");}else{JOptionPane.showMessageDialog(null,s+"不是回文串"); }public static String reverse(String s){char []s1=new char[s.length()];for(int i=0;i<s.length();i++){s1[i]=s.charAt(s.length()-i-1);}String S=new String(s1);return S;}}*///8.4/*public class LQ{public static void main(String []args){String s=JOptionPane.showInputDialog("请输入一串字符");String s1=JOptionPane.showInputDialog("请输入一个字符");char a=s1.charAt(0);int sum=count(s,a);JOptionPane.showMessageDialog(null,s+" 中"+a+" 出现了"+sum+" 次");}public static int count(String s,char a)int i=0,sum=0;for(;i<s.length();i++){if(a==s.charAt(i)){sum++;}}return sum;}}*///8.7/*public class LQ{public static void main(String[]args){String s=JOptionPane.showInputDialog("请输入一个16进制数");int i=parseHex(s);JOptionPane.showMessageDialog(null,s+" 的十进制数是:"+i);}public static int parseHex(String s){int sum=0;for(int i=0;i<s.length();i++){switch(s.charAt(i))case '0':{sum+=0*(int)(Math.pow(16,s.length()-1-i));break;} case '1':{sum+=1*(int)(Math.pow(16,s.length()-1-i));break;} case '2':{sum+=2*(int)(Math.pow(16,s.length()-1-i));break;} case '3':{sum+=3*(int)(Math.pow(16,s.length()-1-i));break;} case '4':{sum+=4*(int)(Math.pow(16,s.length()-1-i));break;} case '5':{sum+=5*(int)(Math.pow(16,s.length()-1-i));break;} case '6':{sum+=6*(int)(Math.pow(16,s.length()-1-i));break;} case '7':{sum+=7*(int)(Math.pow(16,s.length()-1-i));break;} case '8':{sum+=8*(int)(Math.pow(16,s.length()-1-i));break;} case '9':{sum+=9*(int)(Math.pow(16,s.length()-1-i));break;} case 'A':{sum+=10*(int)(Math.pow(16,s.length()-1-i));break;} case 'B':{sum+=11*(int)(Math.pow(16,s.length()-1-i));break;} case 'C':{sum+=12*(int)(Math.pow(16,s.length()-1-i));break;} case 'D':{sum+=13*(int)(Math.pow(16,s.length()-1-i));break;} case 'E':{sum+=14*(int)(Math.pow(16,s.length()-1-i));break;} case 'F':{sum+=15*(int)(Math.pow(16,s.length()-1-i));break;} }}return sum;}}*///8.13/*public class LQ{public static void main(String[] args)String s1=reverse(args[0]);if(s1.equals(args[0])){JOptionPane.showMessageDialog(null,args[0]+"是回文串"); }else{JOptionPane.showMessageDialog(null,args[0]+"不是回文串"); }}public static String reverse(String s){char []s1=new char[s.length()];for(int i=0;i<s.length();i++){s1[i]=s.charAt(s.length()-i-1);}String S=new String(s1);return S;}}*///8.14/*public class LQ{public static void main(String[] args){int sum=0;for(int i=0;i<args.length;i++){sum+=Integer.parseInt(args[i]);}System.out.println(sum);}}public class LQ{public static void main(String[] args) {int sum=0;String[] s=args[0].split("\\s");for(int i=0;i<s.length;i++){sum+=Integer.parseInt(s[i]);}System.out.println(sum);}}*///8.15/*public class LQ{public static void main(String[] args) {int sum=0;for(int i=0;i<args[0].length();i++){if(Character.isUpperCase(args[0].charAt(i))){sum++;}}System.out.println(sum);}}/*//8.17/*public class LQ{public static void main(String[] args){String s=JOptionPane.showInputDialog("请输入字符串"); String []s1=s.split("\\W");for(int i=0;i<s1.length;i++){System.out.println(s1[i]);}}} *///8.18public class LQ{public static void main(String[]args){String s=JOptionPane.showInputDialog("请输入字符串"); String []s1=s.split("\\s");double sum=0;for(int i=0;i<s1.length;i++){sum+=Double.parseDouble(s1[i]);}JOptionPane.showMessageDialog(null,sum);}}*///8.21/*import java.io.*;import java.util.*;public class LQ{public static void main(String[] args)throws Exception {java.io.File file=new java.io.File("Exerise8_21.txt"); Scanner sc=new Scanner(file);double sum=0.0;String s;while(sc.hasNext()){s=sc.next();sum+=Double.parseDouble(s);System.out.println(sum);}}*///8.22/*import java.io.*;import java.util.*;public class LQ{public static void main(String[] args)throws Exception {java.io.File file=new java.io.File("Exerise8_22.txt"); PrintWriter output=new PrintWriter(file);for(int i=0;i<=99;i++){output.print((int)(Math.random()*100)+" ");}output.close();Scanner sc=new Scanner(file);int i=0;int[]a=new int[100];String s;while(sc.hasNext()){s=sc.next();a[i]=Integer.parseInt(s);i++;}Arrays.sort(a);for(i=0;i<100;i++){System.out.print(a[i]+" ");}}}*///9.1/*public class GeometricObject {private String color="white"; private boolean filled;private java.util.Date dateCreated; public GeometricObject(){dateCreated=new java.util.Date(); }public String getColor(){return color;}public void setColor(String color) {this.color=color;}public boolean isFilled(){return filled;}public void setFilled(boolean filled){this.filled=filled;}public java.util.Date getDateCreated(){return dateCreated;}public String toString(){return "created on "+dateCreated +"\ncolor: "+color+" and filled: "+filled;}}*//*class Triangle extends GeometricObject{private double side1;private double side2;private double side3;public Triangle(){side1=1;side2=1;side3=1;}public Triangle(double side1,double side2,double side3){this.side1=side1;this.side2=side2;this.side3=side3;}public void getside(){System.out.println(side1+" "+side2+" "+side3); }public double getArea(){double s=(side1+side2+side3)/2;s=Math.sqrt(s*(s-side1)*(s-side2)*(s-side3)); return s;}public double getPerimeter(){return (side1+side2+side3);}public String toString(){return "Triangle:side1= "+side1+" side2= "+side2+" side3="+side3; }}publicclass LQ{public static void main(String[] args){GeometricObject G=new Triangle(1,1.5,1);G.setColor("yellow");G.setFilled(true);System.out.println(G.getColor());System.out.println(G.isFilled());System.out.println(G.getDateCreated()); ((Triangle) G).getside();System.out.println(((Triangle) G).getArea());}}*///9.2/*class Person{private String name;private String address;private long number;private String Eaddress;public Person(){number=0;}void setname(String name){/doc/3d11885499.html,=name; }String getname(){return name;}void setaddress(String address) {this.address=address;}String getaddress(){return address;}void setnumber(long number) {this.number=number;}long getnumber(){return number;}void seteaddress(String Eaddress) {this.Eaddress=Eaddress;}String geteaddress(){return Eaddress;}public String toString(){return "Person "+"name: "+name+" adress: "+address+" number: "+number+" Eaddress: "+Eaddress;}}class Student extends Person{private String CLASS;final String s1="Grade 1";final String s2="Grade 2";final String s3="Grade 3";final String s4="Grade 4";Student(String CLASS){if(CLASS.charAt(0)==1){this.CLASS=s1;}if(CLASS.charAt(0)==2){this.CLASS=s2;}if(CLASS.charAt(0)==3){this.CLASS=s3;}if(CLASS.charAt(0)==4){this.CLASS=s4;}}public String toString(){return "Student "+"name: "+super.getname()+" adress: "+super.getaddress()+" number: "+super.getnumber()+" Eaddress: "+super.geteaddress();}}class MyDate{private int year;private int mouth;private int day;MyDate(){Calendar c=Calendar.getInstance(); year=c.get(c.YEAR);mouth=c.get(c.MONTH);day=c.get(c.DAY_OF_MONTH)+1; }}class Employee extends Person {private String office;private int charge;//MyDate M;Employee(){office="";}void setoffice(String office){this.office=office;}void setcharge(int charge){this.charge=charge;}public String toString()return "Employee "+"name: "+super.getname()+" adress: "+super.getaddress()+" number: "+super.getnumber()+" Eaddress: "+super.geteaddress();}}class Faculty extends Employee{private String time;private int stand;Faculty(){stand=0;}void settime(String time){this.time=time;}void setstand(int stand){this.stand=stand;}public String toString(){return "Faculty "+"name: "+super.getname()+" adress: "+super.getaddress()+" number: "+super.getnumber()+" Eaddress: "+super.geteaddress();}}class Staff extends Employee{private String Cname;Staff(String Cname){/doc/3d11885499.html,ame=Cname;}public String toString(){return "Staff "+"name: "+super.getname()+" adress: "+super.getaddress()+" number: "+super.getnumber()+" Eaddress: "+super.geteaddress();}}public class LQ{public static void main(String[] args){Person p=new Person();p.setname("承重");p.setaddress("财经大学");p.seteaddress("15142367@/doc/3d11 885499.html,");p.setnumber(1234567);System.out.println(p.toString());Person p1=new Student("1");((Student)p1).setname("承重");((Student)p1).setaddress("财经大学");((Student)p1).seteaddress("15142367@http://www.doczj.co m/doc/3d11885499.html,");System.out.println(((Student)p1).toString());Person p2=new Employee();((Employee)p2).setname("承重");((Employee)p2).setaddress("财经大学");((Employee)p2).seteaddress("15142367@http://www.doczj.c om/doc/3d11885499.html,");System.out.println(((Employee)p2).toString());Employee e1=new Staff("承重");((Staff)e1).setname("承重");((Staff)e1).setaddress("财经大学");((Staff)e1).seteaddress("15142367@/d oc/3d11885499.html,");System.out.println(((Staff)e1).toString());}}*///9.3/*class Account{private long account;private double yu;private double li;protected java.util.Date dateCreated;Account(){yu=0;dateCreated=new java.util.Date(); }void addyu(long yu){this.yu+=yu;}void setli(double li){this.li=li;}void setaccount(long account) {this.account=account;}double getyu(){return yu;}long getaccount(){return account;}void fetch(double yu){this.yu-=yu;}public String toString(){return "account: "+account+" balance"+yu+" time: "+dateCreated;}}class checkingaccount extends Account{private long pri;private long f;void charge(){if(super.getyu()+pri<=0){System.out.println("余额不足");}else{if(super.getyu()-f<-pri){System.out.println("余额不足");}else{super.fetch(f);}}}public checkingaccount(long f,long pri){this.f=f;this.pri=pri;}public String toString(){return "account: "+super.getaccount()+" balance"+super.getyu()+" time: "+super.dateCreated;}}class savingaccount extends Account{private long f;void charge(){if(super.getyu()<=0){System.out.println("余额不足");}else{if(super.getyu()-f<0){System.out.println("余额不足");}else{super.fetch(f);}}}public savingaccount(long f){this.f=f;}public String toString(){return "account: "+super.getaccount()+" balance"+super.getyu()+" time: "+super.dateCreated;}}public class LQ{public static void main(String[] args){Account A=new Account();A.setaccount(123456789);A.setli(0.02);A.addyu(200);System.out.println(A.toString());Account B=new checkingaccount(100,-100);((checkingaccount)B).setaccount(123456789);((checkingaccount)B).setli(0.02);((checkingaccount)B).addyu(200);((checkingaccount)B).charge();System.out.println(((checkingaccount)B).toString());Account C=new savingaccount(50);((savingaccount)C).setaccount(123456789);((savingaccount)C).setli(0.02); ((savingaccount)C).addyu(200); ((savingaccount)C).charge();System.out.println(((savingaccount)C).toString()); }}*///9.4/*class MyStack extends ArrayList{ArrayList list=new ArrayList();public boolean isEmpty(){return list.isEmpty();}public int getSize(){return list.size();}public Object peek(){return list.get(getSize()-1);}public Object pop(){Object o=list.get(getSize()-1);list.remove(getSize()-1);return 0;}public Object push(Object o){list.add(o);return o;}public int search(Object o){return/doc/3d11885499.html,stIndexOf(o);}public String toString(){return "stack: "+list.toString();}}*///9.5/*class Course{private String name;java.util.ArrayList list=new java.util.ArrayList();private int numberOfStudents;public Course(String name){/doc/3d11885499.html,=name; }public void addStudent(String student){list.add(student);}public ArrayList getStudents(){return list;}public String getName(){return name;}}*///9.6/*import java.util.*;public class LQ{public static void main(String[] args){ArrayList list=new ArrayList();list.add(new Object());list.add(new String());list.add(new JFrame());list.add(new Date());for(int i=0;i<list.size();i++){System.out.print(list.get(i));}}}*///10.2/*class Rectangle{private double width;private double height;public Rectangle(){}public Rectangle(double width,double height) {this.width=width;this.height=height;}public double getWidth(){return width;}public void setWidth(double width){this.width=width;}public double getHeight(){return height;}public void setHeight(double height){this.height=height;}public double getArea(){return width*height;}public double getPerunerter(){return 2*(width+height);}}public class LQ extends Rectangle implements Comparable {public LQ(double width,double height){super(width,height);}public int compareTo(Object o){if(getArea()>((LQ)o).getArea())return 1;else if(getArea()<((LQ)o).getArea())return -1;else return 0;}public static void main(String[] args){LQ l=new LQ(12,13);LQ l1=new LQ(12,13);System.out.println(/doc/3d11885499. html,pareTo(l1));}}*///10.3/*interface Colorable{public void howToColor();}class Square1 extends GeometricObject implements Colorable{public void howToColor(){System.out.println(super.getColor());}}class Square2 extends GeometricObject{}class Square3 extends GeometricObject implements Colorable{public void howToColor(){System.out.println(super.getColor());}}class Square4 extends GeometricObject{}class Square5 extends GeometricObject implements Colorable{public void howToColor(){System.out.println(super.getColor());}}public class LQ{public static void main(String[] args){Object[] objects={new Square1(),new Square2(),new Square3(),new Square4(),new Square5()};for(int i=0;i<objects.length;i++){if(objects[i] instanceof Colorable){((Colorable)objects[i]).howToColor();}}}}*///10.4/*class House implements Cloneable,Comparable {private int id;private double area;private java.util.Date whenBuilt;public House(int id,double area){this.id=id;this.area=area;whenBuilt=new java.util.Date();}public double getId(){return id;}public double getArea(){return area;}public java.util.Date getWhenBuilt(){return whenBuilt;}public Object clone(Object o) throws CloneNotSupportedException{House hh=(House)o;return hh;}public int compareTo(Object o){if(area>((House)o).area)return 1;else if(area<((House)o).area)return -1;else return 0;}}public class LQ{public static void main(String[] args) throws CloneNotSupportedException{House h=new House(10,324);House h1=(House)h.clone(h);h.getArea();h1.getArea();System.out.println(h==h1);}}*///10.5/*class Circle extends GeometricObject implements Comparable{private double radius;public Circle(){}public Circle(double redius){this.radius=radius;}public double getRadius(){return radius;}public void setRadius(double radius){this.radius=radius;}public double getArea(){return radius*radius*Math.PI;public double getDiameter(){return 2*radius;}public double getPerimeter(){return 2*radius*Math.PI;}void printCircle(){System.out.println("The circle is created "+getDateCreated()+" and the radius is "+ radius);}public boolean equals(Object obj){return(radius ==((Circle)obj).radius);}public int hashCode(){return (int)(radius*1999711);}public int compareTo(Object o){if(getRadius()==((Circle)o).getRadius())return 0;else return 1;}}public class LQpublic static void main(String[] args){Circle[] C={new Circle(10),new Circle(10)};System.out.println(C[0].compareTo(C[1]));}}*///10.7/*class Octagon extends GeometricObject implements Comparable ,Cloneable{private double side;Octagon(double side){this.side=side;}double getArea(){return (2+4*Math.sqrt(2))*side*side;}public int compareTo(Object o){if(getArea()>((Octagon)o).getArea())return 1;else if(getArea()<((Octagon)o).getArea()) return -1;else return 0;}double getArround(){return 8*side;}public Object clone(){try{return super.clone();}catch(CloneNotSupportedException ex){return null;}}}public class LQ{public static void main(String[] args){Octagon o=new Octagon(15);Octagon i=(Octagon)o.clone();System.out.println(/doc/3d11885499. html,pareTo(i));}}*///10.8/*class Octagon extends GeometricObject{private double side;Octagon(double side){this.side=side;}double getArea(){return (2+4*Math.sqrt(2))*side*side; }double getArround(){return 8*side;}}class Circle extends GeometricObject {private double radius;public Circle(){}public Circle(double redius){this.radius=radius;}public double getRadius(){return radius;}public void setRadius(double radius) {this.radius=radius;}public double getArea(){return radius*radius*Math.PI;}public double getDiameter(){return 2*radius;}public double getPerimeter(){return 2*radius*Math.PI;}void printCircle(){System.out.println("The circle is created "+getDateCreated()+" and the radius is "+ radius);}public boolean equals(Object obj){return(radius ==((Circle)obj).radius);}public int hashCode(){return (int)(radius*1999711);}}class Rectangle extends GeometricObject {private double width;private double height;public Rectangle(){}public Rectangle(double width,double height) {this.width=width;this.height=height;}public double getWidth(){return width;}public void setWidth(double width){this.width=width;}public double getHeight(){return height;}public void setHeight(double height){this.height=height;}public double getArea(){return width*height;}。
实验七输入输出流

实验七输入输出流一、实验目的(1)了解流式输入输出的基本概念;(2)熟悉Java.io包中常用的基本输入输出类;(3)掌握程序与文件之间的基本输入输出操作;二、实验内容1) 把字符串“20102324,张三,男,25,软件工程”,保存到文件”d:\\a.txt”中,并读取打印a.txt文件中的内容。
2) 把我们在聊天界面中发送的消息保存到日志文件里面,在界面上添加一个历史按钮,当点击历史按钮时读取日志文件内容。
三、实验步骤1)把字符串“20102324,张三,男,25,软件工程”,保存到文件”d:\\a.txt”中,并读取打印a.txt文件中的内容。
(1) 定义变量message,值为“20102324,张三,男,25,软件工程”;(2) 创建指向”D:\\a.txt”的文件对象(3) 创建输出流(4) 把message写入流(文件)中(5) 关闭输出流(6) 创建输入流(7) 读取文件内容(8) 打印文件内容(9) 关闭输入流import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;public class FileIO {public static void main(String[] args) {String message = "20102324,张三,男,25,软件工程";File myFile=new File("D:\\a.txt");//写文件try {FileOutputStream fout = new FileOutputStream(myFile,true);//不覆盖try {fout.write(message.getBytes());} catch (IOException e) {e.printStackTrace();}finally{try {fout.close();} catch (IOException e) {e.printStackTrace();}}} catch (FileNotFoundException e) {e.printStackTrace();}//读文件try {FileInputStream fint = new FileInputStream(myFile);byte b[] = new byte[(int) myFile.length()];try {fint.read(b);String s = new String(b);System.out.println(s);} catch (IOException e) {e.printStackTrace();}finally{try {fint.close();} catch (IOException e) {e.printStackTrace();}}}catch (FileNotFoundException e) {e.printStackTrace();}}}2)把我们在聊天界面中发送的消息保存到日志文件里面,在界面上添加一个历史按钮,当点击历史按钮时读取日志文件内容。
java编程基础第7章_输入流与输出流

for (File f : files) {
if (f.isFile()) {
System.out.println("文件:" + f);
} else {
执行结果如下:
System.out.println("目录:" + f);
文件:C:\Program Files\Java\jdk1.6.0_18\src.zip }
第七章
流与文件
目标
Ø 掌握File类的使用 Ø 理解流的不同分类 Ø 掌握InputStream和OutputStream的使用 Ø 掌握常用过滤流的使用 Ø 掌握Reader和Writer的使用 Ø 理解序列化和反序列化的概念 Ø 掌握对象流的使用
-2-
文件
• 文件
文件可认为是相关记录或放在一起的数据的集合;文件可以存储在硬盘、
文件:C:\Program Files\Java\jdk1.6.}0_18\COPYRIGHT 目录:C:\Program Files}\Java\jdk1.6.0_18\jre 文 …件 …: ……C:…\P}rogram Files\Java\jdk1.6.0_18\LICENSE }
-6-
文件列表器-2
-5-
文件列表器-1
• listFiles方法实例
利用列表方法将JDK根目录下的目录或文件的名称列举出来,并标明
文件或目录。 代码如下:
public class ListFileDemo {
public static void main(String[] args) {
// 根据路径名称创建File对象
-3-
File类实例
创建一个File对象,检验文件是否存在,若不存File对在象就只创是一建个,引用然,后它可对
java——第十章PPT课件

BufferedReader br = new BufferedReader(new InputStreamReader(System.in), boolean append)
它们可以引发IOException或SecurityException异 常。这里,是文件的全称路径,是描述该文件的File 对象。如果append为true,文件以设置搜索路径模式 打开。
从键盘读取字符串,使用readLine()方法,它是 BufferedReader 类的成员。这个方法的一般使用 形式如下。
String readLine() throws IOException 该方法返回一个String对象。
三、向控制台写输出 Java允许使用System.out向控制台写数据,但建议仅用 于调试程序时。对于实际的程序,Java推荐的向控制台 写数据的方法是用PrintWriter流。PrintWriter是基于 字符的类,用基于字符的类向控制台写数据使程序更为 国际化。 PrintWriter(OutputStream outputStream, boolean flushOnNewline)
System.in是InputStream的对象;System.out和 System.err是PrintStream的对象。
二、读取控制台输入 在Java中,控制台输入由从System.in读取数据来完 成。为获得属于控制台的字符流,在BufferedReader 对象中包装了System.in。BufferedReader支持缓冲 输入流,它最常见的构造函数如下:
实验七输入输出流

一、实验目的:
1.理解Java输入输出的实现机制;
2.掌握常用的输入输出类的功能及方法;
二、实验内容:
1、在下面的程序中我们把11至20这10个long型数据写入到一个名字为文件中,然后读出并显示这些数据中的奇数,请将程序填写完整。
import .*;
public classFileout
{【代码2】;
}
for(long i=0;i<h;i++)
{【代码3】;
.print(","+fi.readLong());
}
fi.close();
}
catch(IOException e){}
}
}
2、编写一个java应用程序,将已经存在的扩展名为.txt文本文件加密后存入另一个文件文件中
程序中代码位置加上适当的语句文件加密程序模板
}
【代码3】// out将数组b的前n单元写到文件。
}
【代码3】//out关闭。Fra bibliotekin=【代码4】//创建指向fileTwo的字符输入流。
.println("加密后的文件内容:");
while((n=in.read(b))!=-1)
{
String str=new String(b,0,n);
.println(str);
{
File file=new File("");
File tempFile=new File("");
try{
FileReader inOne=【代码1】//创建指向文件file的输入流。
BufferedReader inTwo=【代码2】//创建指向inOne file的输入流。
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第10章异常测试题2010-12-11
一、选择题
1.假设文件中的信息为abcd,下面代码执行的结果是什么:
public static void main(String[]args)throws IOException{ FileInputStream fis=new FileInputStream("a.txt");
int data=fis.read();
System.out.println(data);
fis.close();//a的ASCII码为97,A的为65
}
A.97
B.a
C.-1
D.编译出错
E.运行出错
2.假设文件中的信息为abcd,下面代码执行的结果是什么:
public static void main(String[]args)throws Exception{
FileInputStream fis=new FileInputStream("a.txt");
int data=fis.readInt();
System.out.println(data);
fis.close();
}
A.97
B.a
C.-1
D.编译出错
E.运行出错
3.下面程序执行的结果是什么:
public static void main(String[]args)throws IOException{
//TODO Auto-generated method stub
FileOutputStream fos=new FileOutputStream("a.txt");
fos.write Int(97);
fos.close();
}
A.文件中写入97
B.文件中写入a
C.文件中写入-1
D.编译出错
E.运行出错
4.下面程序执行的结果是什么:
public static void main(String[]args)throws IOException{
FileOutputStream fos=new FileOutputStream("a.txt");
fos.write(97);
}
A.文件中写入97
B.文件中写入a
C.文件中写入-1
D.编译出错
E.运行出错
5.下面程序执行的结果是什么:
public static void main(String[]args)throws IOException{ BufferedOutputStream fos=new BufferedOutputStream("a.txt");
fos.write(97);
A.文件中写入97
B.文件中写入a
C.文件中写入-1
D.编译出错
E.运行出错
F.没有数据的录入
6.下面程序执行的结果是什么:
public static void main(String[]args)throws IOException{
BufferedOutputStream fos=new BufferedOutputStream(new FileOutputStream("b.txt"));
fos.write(97);
}
A.文件中写入97
B.文件中写入a
C.文件中写入-1
D.编译出错
E.运行出错
F.其他情况
7.完成下面代码,实现从当前项目根目录中把a.txt拷贝到c盘根目录中,备份文件名字为a.txt
BufferedInputStream bis=new BufferedInputStream(_"a.txt"__);
BufferedOutputStream bos=new BufferedOutputStream(__"a.txt"___);
__________________;
byte[]b=new byte[1024];
int length=-1;
while(___________________){
(length=bis.read(b))!=-1
_____________________;
bos.write(b,0,length);
}
bos.close();
bis.close();
8.现开发一个功能对Date进行格式化,转换为年-月-日格式.当前日期假设为2010年9月1日,执行此方法得到什么结果:
package com.test;
import java.io.IOException;
import java.sql.Date;
import java.text.SimpleDateFormat;
public class Test{
public static String formatDate(){
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
return sdf.format(new Date());
}
public static void main(String[]args){
System.out.println(formatDate());
}
A.编译出错
B.运行出错
C.2010-09-01
D.1970-01-01
9.现开发一个功能对Date进行格式化,转换为年-月-日格式.当前日期假设为2010年9月1日,执行此方法得到什么结果:
package com.test;
import java.io.IOException;
import java.util.Date;
import java.text.SimpleDateFormat;
public class Test{
public static void formatDate(){
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
return sdf.format(new Date());
}
public static void main(String[]args){
System.out.println(formatDate());
}
}
A.编译出错
B.运行出错
C.2010-09-01
D.1970-01-01
10.下面程序执行的结果是什么:
public static void addStudent(Student stu)throws IOException{
DataOutputStream dos=new DataOutputStream(new FileOutputStream("stu.db")); dos.writeInt(stu.getId());
dos.writeDouble(stu.getResult());
dos.writeUTF(stu.getName());
dos.close();
}
public static void loadStudent()throws IOException{ DataInputStream dis=new DataInputStream(new FileInputStream("stu.db"));
double result=dis.readDouble();
int id=dis.readInt();
String name=dis.readUTF();
System.out.println(id+"\t"+result+"\t"+name);
dis.close();
}
public static void main(String[]args)throws IOException{ Student stu=new Student(1,88,"tom");
addStudent(stu);
loadStudent();
}
A.编译出错
B.运行出错
C.输出188tom
D.无法成功还原写入数据
11.请完善下面的代码,成功的采用字符流读取文件内容进行输出: public static void test2()throws IOException{
FileInputStream fis=new FileInputStream("a.txt");
InputStreamReader isr=new InputStreamReader(fis);
BufferedReader br=new BufferedReader(isr);
String line=null;
while((line=br.readLine())!=null){
System.out.println(line);
}
br.close();
}。