JAVA实验3.docx

实验三 内部类、常用类及异常类的用法1实验目的（1）掌握Java中内部类的用法、异常类的用法 （2）掌握Java中String类常用方法、StringBuilder类的用法；（3）掌握System类、Date类、Calender类、DateFormat类、NumberFormat类、Random类与BigInteger及BigDecimal类的用法； （4）掌握Java中正则表达式的基本用法；2实验内容实验题1 修改实验二实验题4，声明一个局部变量String text = ;然后通过循环把数组中的成员（有序）添加到text中，修改方法JOptionPane.showMessageDialog();参数以显示text。package .nwsuaf.jp.p4.data;public abstract class Product implements Comparableprotected String name;protected float price;protected static int count;public Product(String name, float price) super(); = name;this.price = price;count+;public String getName() return name;public void setName(String name) = name;public float getPrice() return price;public void setPrice(float price) this.price = price;public static int getCount() return count;public static void setCount(int count) Product.count = count;public int compareTo(Product p)return new Float(p.getPrice().compareTo(price);package .nwsuaf.jp.p4.data;import .nwsuaf.jp.p4.data.Product;public class Mobile extends Productpublic Mobile(String name,float price)super(name,price);Overridepublic String toString() return name+price+RMB;package .nwsuaf.jp.p4.data; import .nwsuaf.jp.p4.data.Product; public class Mp3Player extends Product public int memory; public Mp3Player(String name,int memory,float price) super(name,price); this.memory=memory; public int getMemory() return memory; public void setMemory(int memory) this.memory = memory; Override public String toString() return name+(+memory+MB),+price+RMB; package .nwsuaf.jp.p4;import java.util.Arrays;import javax.swing.JOptionPane;.nwsuaf.jp.p4.data.Mp3Player;import .nwsuaf.jp.p4.data.Mobile;import .nwsuaf.jp.p4.data.Product;public class Store public static void main(String args) Mobile m1=new Mobile(E365 on China Mobile, 1780.0f);Mobile m2=new Mobile(M330 on China Mobile, 1450.0f); Mp3Player p1=new Mp3Player(Meizo X3, 256, 399.0f); Mp3Player p2=new Mp3Player(Meizo E5, 512, 580.0f); Mp3Player p3=new Mp3Player(Xlive XM Mp3Player, 256, 930.0f); Product ps=m1,m2,p1,p2,p3; Arrays.sort(ps); String text=; for(int a=0;aps.length;a+) text+=psa.toString()+n; JOptionPane.showMessageDialog(null,The products are:+nn+text+nn+There are+Product.getCount()+products.); 实验题2 用StringBuiler text = ;替换String text = ;然后通过循环使用StringBuiler类的append方法向text中把数组中的成员（按价格有序）添加到text中，修改方法JOptionPane.showMessageDialog()的参数以显示text。运行结果如图3-1所示。图3-1思考问题：对比分析StringBuiler与String的区别。解：一个String对象的长度是固定的，不能改变它的内容，或者是附加新的字符至String对象中。您也许会使用+来串联字符串以达到附加新字符或字符串的目的，但+会产生一个新的String实例。而使用StringBuiler类中的append方法则是将新的字符串添加到已经开辟的内存中，不会增加新的内存来存放新增的字符串。使用StringBuiler类中的append方法效率比较高，并且使用StringBuiler类中的append方法可以完全替代String类。Storel类package .nwsuaf.jp.p4;import java.util.Arrays;import javax.swing.JOptionPane;import .nwsuaf.jp.p4.data.Mp3Player;import .nwsuaf.jp.p4.data.Mobile;import .nwsuaf.jp.p4.data.Product;public class Store public static void main(String args) Mobile m1=new Mobile(E365 on China Mobile, 1780.0f);Mobile m2=new Mobile(M330 on China Mobile, 1450.0f); Mp3Player p1=new Mp3Player(Meizo X3, 256, 399.0f); Mp3Player p2=new Mp3Player(Meizo E5, 512, 580.0f); Mp3Player p3=new Mp3Player(Xlive XM Mp3Player, 256, 930.0f); Product ps=m1,m2,p1,p2,p3; Arrays.sort(ps); /String text=; StringBuilder text=new StringBuilder(); for(int a=0;aps.length;a+) text.append(psa+n); JOptionPane.showMessageDialog(null,The products are:+nn+text+nn+There are+Product.getCount()+products.); 实验题3 从网上加载一个门户网站首页文件，用所学正则表达式知识，提取出其中所有邮箱地址。提示：读取文件的语句为BufferedReader br = new BufferedReader(new FileReader(d:sharedxxx.html);while(line= br.readLine()!=null)parse(line);基本要求：编写parse方法，完成上述功能。package text3.d3;import java.io.BufferedReader;import java.io.FileReader;import java.io.IOException;import java.util.regex.Matcher;import java.util.regex.Pattern;public class Email public Email()private static void parse(String text)String regex=w.-+w.-+.w+;Pattern p=Ppile(regex);Matcher m=p.matcher(text);while (m.find()String string =m.group();System.out.println(string);public static void main(String args)tryBufferedReader reader=new BufferedReader(new FileReader(f:sina.htm);String text=;while(text=reader.readLine()!=null)parse(text); catch(IOException e) e.printStackTrace(); 实验题4 修改实验二实验题4，在Product类中添加销售日期属性及销售额属性，在sell方法中对其初始化，比较Date类与Calender类的用法,最后使用SimpleDateFormat类对销售日期进行格式化；用类DecimalFormat的相关方法格式化属性sales，熟悉DecimalFormat的用法。运行结果如图3-2所示。package .nwsuaf.jp.p4.data;public abstract class Product implements Comparable protected String name;protected float price;protected static int count; protected Product (String name,float price) =name;this.price=price;+count;public String getName() return name;public float getPrice() return price;public static int getCount() return count;public int compareTo(Product product) return new Float(product.getPrice().compareTo(price);package .nwsuaf.jp.p4.data;public class Mobile extends Product public Mobile (String name,float price) super(name,price);public String toString() return name+price+RMB;package .nwsuaf.jp.p4.data;public class Mp3Player extends Product public int memory;public Mp3Player(String name,int memory,float price) super(name,price);this.memory=memory;public int getMemory() return memory;public void setMemory(int memory) this.memory = memory;Overridepublic String toString() return name+(+memory+MB),+price+RMB;package .nwsuaf.jp.p4;import java.util.Arrays;import javax.swing.JOptionPane;import .nwsuaf.jp.p4.data.Mp3Player;import .nwsuaf.jp.p4.data.Mobile;import .nwsuaf.jp.p4.data.Product;public class Store public static void main (String args) Mobile m1=new Mobile(E365 on China Mobile,1780.0f);Mobile m2=new Mobile(M330 on China Mobile,1450.0f);Mp3Player player1= new Mp3Player(Meizo X3,256,399.0f);Mp3Player player2= new Mp3Player(Meizo E5,512,580.0f);Mp3Player player3= new Mp3Player(Xlive XM MP3Player,256,930.0f);Product products =m1,m2,player1,player2,player3;Arrays.sort(products);String text=;for (int a=0;aproducts.length;+a) text+= productsa.toString()+n;JOptionPane.showMessageDialog(null, The products are:+nn+text+nn+There are +Product.getCount()+ products.);图3-2实验题 5 编写一个程序，输入一个班某门课程成绩，统计及格人数、不及格人数平均分。为此设计一个异常类，当输入的成绩小于0分或大于100分时，抛出异常，程序将捕捉这个异常，并作出相应处理。基本要求： 编写完整程序实验过程：先设计Input类，其中包含judge函数用来判断输入的成绩是否合法并分别输出不合法原因。在主方法中实现抛出异常。其次设计两个异常类分别是：subException和beyondException实现成绩大于100分和小于0分的异常。最后在主函数中编写成绩输入方法。package text3.d5;public class subException extends ArithmeticExceptionprivate static final long serialVersionUID =1L;public subException () super();public subException(String string) super(string);package text3.d5;public class beyondException extends ArithmeticException private static final long serialVersionUID =1L;public beyondException ()super();public beyondException (String string) super(string);package text3.d5;import java.util.Scanner;public class Input public static void judge (double i) throws subException,beyondException if(i100) throw new beyondException (成绩不能大于100!);public static void main (String args) int i=1;int passnum=0;int nopassnum=0;System.out.println(请输入学生成绩,以“-1”结束!);System.out.println(第+i+位同学的成绩为:);SuppressWarnings(resource)Scanner reader = new Scanner(System.in);double sum=0;double x= reader.nextDouble();while (x!=-1) tryjudge(x);if(x60) passnum= passnum+1;sum+=x; catch(subException e1) System.out.println(e1);i-=1;catch(beyondException e2) System.out.println(e2);i-=1;i=i+1;System.out.println(第+i+位学生的成绩为：);x=reader.nextDouble();System.out.println(平均分为:+sum/(nopassnum+passnum);System.out.println(及格人数为:+passnum);System.out.println(不及格人数为:+nopassnum);*实验题6 设计类ReflectTester，该类中有一方法copy（Object obj），该方法能够创建一个和参数obj同样类型的对象，然后把obj对象中所有属性复制到新建对象中，并将它返回。基本要求：设计相关类完成上述功能（只要求复制简单JavaBean，且每个JavaBean的每个属性都有public类型的getXxx()和setXxx()方法）。package text.d6;public class Product private String name;private float price;public String getName() return name;public void setName(String name) = name;public float getPrice() return price;public void setPrice(float price) this.price = price;public Product(String name,float price) / TODO 自动生成的构造函数存根super();=name;this.price=price;public Product() / TODO 自动生成的构造函数存根super();package text3.d6;import java.lang.reflect.Field;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import text.d6.Product;public class reflectTester public reflectTester() / TODO 自动生成的构造函数存根SuppressWarnings( rawtypes, unchecked )public Object copy(Object obj) throws InstantiationException,IllegalAccessException,IllegalArgumentException,InvocationTargetException,NoSuchMethodException,SecurityException Class classType=obj.getClass();System.out.println(Class+classType.getName();Object objectOfCopy = classType.getConstructor(new Class).newInstance(new Object);Field fields = classType.getDeclaredFields();for(Field field:fields)String fieldName = field.getName();String firstLetter = fieldName.substring(0,1).toUpperCase();String getMethodName = get+firstLetter + fieldName.substring(1);String setMethodName = set+firstLetter + fieldName.substring(1);Method getMethod = classType.getMethod(getMethodName,new Class);Method setMethod = classType.getMethod(setMethodName,field.getType();Object value = getMethod.invoke(obj,new Object);System.out.println(fieldName+,+value);setMethod.invoke(objectOfCopy, new Objectvalue);re