湖南大學JAV第三次作業(yè)

1、精選優(yōu)質(zhì)文檔-傾情為你奉上第六章 Java輸入輸出1、說明程序功能：import java.io.*;public class CharWrite public static void main(String args) try FileWriter fw=new FileWriter("charset.txt "); for ( int i=32;i<126;i+) fw.write(i); fw.close(); catch (IOException e) 答：向文件charset.txt中輸入ASCII碼從32到126共94個字符。2、先用隨機函數(shù)產(chǎn)生出任意的2

2、0個整數(shù)，再按由小到大的順序排序，然后將結(jié)果寫入一個文件中，最后從該文件中讀出后顯示出來。請分別用順序文件和隨機文件的讀寫形式進行編程測試。代碼：import java.io.BufferedInputStream;import java.io.BufferedOutputStream;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;im

3、port java.io.OutputStream;import java.util.Random;public class RandNum public static void main(String args) Random rand = new Random();/實例化一個產(chǎn)生隨機數(shù)的類 int num = new int20;/定義一個整型數(shù)組，用來存儲產(chǎn)生的隨機數(shù) int r = 0;/隨機數(shù) for(int i = 0;i<num.length;i+) r = rand.nextInt(1000);/產(chǎn)生一個1000以內(nèi)的隨機數(shù) /放入數(shù)組 numi = r; int k;

4、 /進行排序 for(int i = 0;i<num.length;i+) for(int j = 0;j<i;j+) if(numi < numj) k = numi; numi = numj; numj = k; RandNum rn = new RandNum(); /寫入文件 rn.WriteFile("src/123",num); /讀取文件 int x = rn.ReadFile("src/123"); /讀取的數(shù)組 for(int i = 0;i<num.length;i+) System.out.print(xi

5、+ "t"); if(i%5 = 4) System.out.println(); /* * 讀取文件的方法 * param path */ public int ReadFile(String path) int a = null; try / 實例化一個File輸入流對象InputStream is = new FileInputStream(path);/ 實例化一個Buffer輸入流對象BufferedInputStream bs = new BufferedInputStream(is);int length = bs.available();/讀取第一個為數(shù)組大

6、小int k = bs.read();/用來計數(shù)int count = 0;/實例化數(shù)組a = new intk;String str = ""/中間變量for(int i = 0;i<length;i+)/繼續(xù)讀取k = bs.read();/若讀取的不是換行if(k != 13 && k != 10 && k != -1)/讀取到空格while(k != 32)str += (char)k;k = bs.read();/把字符串里的數(shù)字轉(zhuǎn)換成整型放入數(shù)組中acount = Integer.parseInt(str);count+;s

7、tr = ""/清空字符串is.close();bs.close();System.out.println("讀取成功"); catch (FileNotFoundException e)System.out.println("找不到指定文件，請確認文件路徑"); catch (IOException e) e.printStackTrace(); return a; /* * 寫入文件 * param path 路徑 * param a 數(shù)組 */ public void WriteFile(String path,int a)tr

8、y / 實例化一個File輸出流OutputStream os = new FileOutputStream(path);/ 實例化一個Buffered輸出流BufferedOutputStream bos = new BufferedOutputStream(os);/寫入數(shù)組大小bos.write(a.length);/寫入換行符bos.write(13);bos.write(10);/循環(huán)寫入數(shù)組的值for(int i = 0;i<a.length;i+)bos.write(Integer.toString(ai).getBytes();/寫入1個空格bos.write(32);b

9、os.flush();bos.close();os.close();System.out.println("寫入成功"); catch (FileNotFoundException e) e.printStackTrace(); catch (IOException e) e.printStackTrace(); 截圖3、統(tǒng)計一個文本文件中單詞的個數(shù)。文本文件的名字從命令行中獲得。代碼import java.io.FileReader;import java.io.IOException;import java.util.StringTokenizer;public cla

10、ss test public static void main(String args) throws IOException FileReader fileReader=new FileReader(args0); StringBuffer stringBuffer=new StringBuffer(); char b=new char506; while(fileReader.read(b,0,505)!=-1) stringBuffer.append(b); StringTokenizer stringTokenizer=new StringTokenizer(stringBuffer.

11、toString(); System.out.println("文本文件中單詞的個數(shù)為："+stringTokenizer.countTokens(); 結(jié)果截圖第七章 Java圖形用戶界面1、閱讀下面的程序，回答問題。 import java.awt.*; import javax.swing.*; public class T extends JFrame public T ( ) super("GridLayout"); Container con=this.getContentPane(); con.setLayout(new GridLayou

12、t(2,3); con.add(new JButton("a"); con.add(new JButton("b"); con.add(new JButton("c"); con.add(new JButton("d"); con.add(new JButton("e"); con.add(new JButton("f"); setSize(200, 80); setVisible(true); public static void main(String args) new

13、 T(); 畫圖表示程序運行后的圖形界面。如果程序通過實現(xiàn)某個接口處理按鈕的動作事件，則該接口名為何？接口中的方法頭聲明如何？答：實現(xiàn)的接口是ActionListener，該接口的方法聲明是public void actionPerformed(ActionEvent e)2、編寫一個簡單的計算器，要求圖形用戶界面如下圖所示。代碼import java.awt.BorderLayout;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionL

14、istener;import java.util.HashSet;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JPanel;import javax.swing.JTextField;public class jisuanqi public static void main(String args) new MyCalculator(); class MyCalculator private double result=0.0; private String string=""

15、; private JTextField jtext = new JTextField("",15); String str=new String"Clear","+","0","1","2","3","-","*",".","4","5","6","/","%","=",&qu

16、ot;7","8","9" public MyCalculator() JFrame frame = new JFrame("calculator"); frame.setBounds(400,200,450,250); JPanel jp = new JPanel(new GridLayout(3,6,10,10); frame.setLayout(new BorderLayout(); frame.add(jtext,BorderLayout.NORTH); frame.add(jp,BorderLayout.CENTE

17、R); final HashSet hashSet=new HashSet(); class MyEvent implements ActionListener public void actionPerformed(ActionEvent e) for(Object k:hashSet) if(e.getSource()=k) JButton jb=(JButton)k; if(jb.getText()="Clear") jtext.setText(""); else jtext.setText(jtext.getText()+jb.getText()

18、; if(jb.getText()="=") char c=jtext.getText().toCharArray(); int i; for(i=0;i<c.length;i+) if(ci='+'|ci='-'|ci='*'|ci='/'|ci='%') break; String astr=String.copyValueOf(c, 0, i); String bstr=String.copyValueOf(c,i+1,c.length-i-2); MyCompute mycompu

19、te = new MyCompute(); result=pute(Double.parseDouble(astr),Double.parseDouble(bstr),ci); jtext.setText(""+result); for(int i=0;i<18;i+) JButton b=new JButton(stri); jp.add(b); b.addActionListener(new MyEvent(); hashSet.add(b); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.

20、setVisible(true); class MyCompute private double result=0.0; public MyCompute() public double compute(double a,double b,char c) if(c='+') result=a+b; if(c='-') result=a-b; if(c='*') result=a*b; if(c='/') result=a/b; if(c='%') result=a%b; return result; 3. 編程題：

21、請編寫一個簡單的用戶登錄程序。要求使用圖形用戶界面，* 用戶名和密碼假定均為java，且密碼輸入時全部顯示為星號（*）。 */代碼public class TheExam7_3 public static void main(String args) MyLand my=new MyLand(); class MyLand int a=0; public MyLand() JFrame frame = new JFrame(); frame.setBounds(450,300,370,220); Font font=new Font("宋體",Font.PLAIN,30);

22、 frame.setFont(font); frame.setLayout(new BorderLayout(); JPanel paneltop = new JPanel(); paneltop.add(new JLabel("用戶登陸",JLabel.CENTER); frame.add(paneltop,BorderLayout.NORTH); frame.setVisible(true); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JPanel panel_1 = new JPanel(new Gri

23、dLayout(3,1); frame.add(panel_1,BorderLayout.CENTER); JPanel panel_11 = new JPanel(new FlowLayout(); JPanel panel_12 = new JPanel(new FlowLayout(); JPanel panel_13 = new JPanel(new GridLayout(1,5); panel_1.add(panel_11); panel_1.add(panel_12); panel_1.add(panel_13); panel_11.add(new JLabel("用戶名

24、："); final JTextField text1 = new JTextField("",10); panel_11.add(text1); panel_12.add(new JLabel("用戶密碼："); final JPasswordField text2 = new JPasswordField("",10); text2.setEchoChar('*'); panel_12.add(text2); JButton b=new JButton("確定"); class MyE

25、xam7_3 implements ActionListener public void actionPerformed(ActionEvent e) JDialog dialog=new JDialog(); dialog.setBounds(450, 200,560,400); dialog.setVisible(true); Font font1 = new Font("宋體",Font.BOLD,70); dialog.setFont(font1); if(text1.getText().equalsIgnoreCase("java")&

26、&String.valueOf(text2.getPassword().equals("java") dialog.add(new JLabel("登陸成功！",JLabel.CENTER); / new MyCalculator(); else dialog.add(new JLabel("密碼或用戶名錯誤！",JLabel.CENTER); b.addActionListener(new MyExam7_3(); panel_13.add(new Label(" "); panel_13.add(new

27、 Label(" "); panel_13.add(b); panel_13.add(new Label(" "); panel_13.add(new Label(" "); 結(jié)果截圖第八章 Java多線程技術(shù)1、程序如下：public class Borley extends Threadpublic static void main(String argv) Borley b = new Borley(); b.start(); public void run() System.out.println("Running&

28、quot;); 下面描述正確的是：（B）單選A) 通過編譯和運行但是沒有任何輸出。B) 通過編譯，運行后輸出"Running"C) 編譯出錯，沒有線程可供運行D) 編譯出錯，沒有權(quán)限使用Thread2、 編寫程序，啟動1000個線程，每個線程給初值為0的變量sum加1。（提示，需要通過引用傳遞，將sum傳遞給每個線程，為了能夠進行引用傳遞，需要定義一個Integer包裝對象來保存sum）。代碼public class Borley extends Threadpublic static void main(String argv)/通過Integer包裝對象sumInteg

29、er sum = new Integer(0);/循環(huán)1000次，開啟1000個線程for(int i = 0;i<1000;i+)Borley b = new Borley(sum);b.start();private Integer sum;public Borley(Integer sum)this.sum = sum;public void run() sum+;System.out.println(sum);截圖3、利用多線程技術(shù)模擬龜兔賽跑的場面。提示：先設(shè)計一個線程類模擬兩個參與賽跑的選手的行為；然后創(chuàng)建該類的兩個對象分別代表烏龜和兔子；讓兔子跑快些，但在路上睡眠休息時間長

30、些，而烏龜跑慢些卻不休息；當某個選手到達終點時其線程運行結(jié)束；二個選手均到達終點時，顯示并祝賀獲勝選手，然后主線程結(jié)束。代碼Import java.util.Date;public class xiancheng extends Thread private int tortoise_walk = 0; / 烏龜已跑長度存放變量 private int rabbit_walk = 0; / 兔子已跑長度存放變量 private int finish = 1000; / 終點 private volatile boolean hasWinner = false;/ 勝利者誕生 /* class

31、Tortoise_Run implements Runnable public void run() try while (!hasWinner) if (tortoise_walk % 100 = 0 && (tortoise_walk != 0|tortoise_walk>=finish) /烏龜每100米休息500毫秒 Thread.sleep(500); tortoise_walk+; System.out.println("烏龜已跑"+tortoise_walk+"米"); catch (InterruptedException e) e.printStackTrace(); class Rabbit_Run implements Runnable public void run() try while (!hasWinner) if (rabbit_walk % 20 = 0 && (rabbit_walk != 0|rabbit_walk>=finish) /兔子每20米休息500毫秒 System.out.pr