JAVA實驗3.docx

實驗三 內部類、常用類及異常類的用法1實驗目的（1）掌握Java中內部類的用法、異常類的用法 （2）掌握Java中String類常用方法、StringBuilder類的用法；（3）掌握System類、Date類、Calender類、DateFormat類、NumberFormat類、Random類與BigInteger及BigDecimal類的用法； （4）掌握Java中正則表達式的基本用法；2實驗內容實驗題1 修改實驗二實驗題4，聲明一個局部變量String text = ;然后通過循環(huán)把數(shù)組中的成員（有序）添加到text中，修改方法JOptionPane.showMessageDialog();參數(shù)以顯示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.); 實驗題2 用StringBuiler text = ;替換String text = ;然后通過循環(huán)使用StringBuiler類的append方法向text中把數(shù)組中的成員（按價格有序）添加到text中，修改方法JOptionPane.showMessageDialog()的參數(shù)以顯示text。運行結果如圖3-1所示。圖3-1思考問題：對比分析StringBuiler與String的區(qū)別。解：一個String對象的長度是固定的，不能改變它的內容，或者是附加新的字符至String對象中。您也許會使用+來串聯(lián)字符串以達到附加新字符或字符串的目的，但+會產生一個新的String實例。而使用StringBuiler類中的append方法則是將新的字符串添加到已經開辟的內存中，不會增加新的內存來存放新增的字符串。使用StringBuiler類中的append方法效率比較高，并且使用StringBuiler類中的append方法可以完全替代String類。Storel類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.); 實驗題3 從網上加載一個門戶網站首頁文件，用所學正則表達式知識，提取出其中所有郵箱地址。提示：讀取文件的語句為BufferedReader br = new BufferedReader(new FileReader(d:sharedxxx.html);while(line= br.readLine()!=null)parse(line);基本要求：編寫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(); 實驗題4 修改實驗二實驗題4，在Product類中添加銷售日期屬性及銷售額屬性，在sell方法中對其初始化，比較Date類與Calender類的用法,最后使用SimpleDateFormat類對銷售日期進行格式化；用類DecimalFormat的相關方法格式化屬性sales，熟悉DecimalFormat的用法。運行結果如圖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.);圖3-2實驗題 5 編寫一個程序，輸入一個班某門課程成績，統(tǒng)計及格人數(shù)、不及格人數(shù)平均分。為此設計一個異常類，當輸入的成績小于0分或大于100分時，拋出異常，程序將捕捉這個異常，并作出相應處理?；疽螅?編寫完整程序實驗過程：先設計Input類，其中包含judge函數(shù)用來判斷輸入的成績是否合法并分別輸出不合法原因。在主方法中實現(xiàn)拋出異常。其次設計兩個異常類分別是：subException和beyondException實現(xiàn)成績大于100分和小于0分的異常。最后在主函數(shù)中編寫成績輸入方法。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 (成績不能大于100!);public static void main (String args) int i=1;int passnum=0;int nopassnum=0;System.out.println(請輸入學生成績,以“-1”結束!);System.out.println(第+i+位同學的成績?yōu)?);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+位學生的成績?yōu)椋?;x=reader.nextDouble();System.out.println(平均分為:+sum/(nopassnum+passnum);System.out.println(及格人數(shù)為:+passnum);System.out.println(不及格人數(shù)為:+nopassnum);*實驗題6 設計類ReflectTester，該類中有一方法copy（Object obj），該方法能夠創(chuàng)建一個和參數(shù)obj同樣類型的對象，然后把obj對象中所有屬性復制到新建對象中，并將它返回?；疽螅涸O計相關類完成上述功能（只要求復制簡單JavaBean，且每個JavaBean的每個屬性都有public類型的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 自動生成的構造函數(shù)存根super();=name;this.price=price;public Product() / TODO 自動生成的構造函數(shù)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 自動生成的構造函數(shù)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