湖南大学JAV第三次作业

1、精选优质文档-倾情为你奉上第六章 Java输入输出1、说明程序功能：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中输入ASCII码从32到126共94个字符。2、先用随机函数产生出任意的2

2、0个整数，再按由小到大的顺序排序，然后将结果写入一个文件中，最后从该文件中读出后显示出来。请分别用顺序文件和随机文件的读写形式进行编程测试。代码：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();/实例化一个产生随机数的类 int num = new int20;/定义一个整型数组，用来存储产生的随机数 int r = 0;/随机数 for(int i = 0;i<num.length;i+) r = rand.nextInt(1000);/产生一个1000以内的随机数 /放入数组 numi = r; int k;

4、 /进行排序 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(); /写入文件 rn.WriteFile("src/123",num); /读取文件 int x = rn.ReadFile("src/123"); /读取的数组 for(int i = 0;i<num.length;i+) System.out.print(xi

5、+ "t"); if(i%5 = 4) System.out.println(); /* * 读取文件的方法 * param path */ public int ReadFile(String path) int a = null; try / 实例化一个File输入流对象InputStream is = new FileInputStream(path);/ 实例化一个Buffer输入流对象BufferedInputStream bs = new BufferedInputStream(is);int length = bs.available();/读取第一个为数组大

6、小int k = bs.read();/用来计数int count = 0;/实例化数组a = new intk;String str = ""/中间变量for(int i = 0;i<length;i+)/继续读取k = bs.read();/若读取的不是换行if(k != 13 && k != 10 && k != -1)/读取到空格while(k != 32)str += (char)k;k = bs.read();/把字符串里的数字转换成整型放入数组中acount = Integer.parseInt(str);count+;s

7、tr = ""/清空字符串is.close();bs.close();System.out.println("读取成功"); catch (FileNotFoundException e)System.out.println("找不到指定文件，请确认文件路径"); catch (IOException e) e.printStackTrace(); return a; /* * 写入文件 * param path 路径 * param a 数组 */ public void WriteFile(String path,int a)tr

8、y / 实例化一个File输出流OutputStream os = new FileOutputStream(path);/ 实例化一个Buffered输出流BufferedOutputStream bos = new BufferedOutputStream(os);/写入数组大小bos.write(a.length);/写入换行符bos.write(13);bos.write(10);/循环写入数组的值for(int i = 0;i<a.length;i+)bos.write(Integer.toString(ai).getBytes();/写入1个空格bos.write(32);b

9、os.flush();bos.close();os.close();System.out.println("写入成功"); catch (FileNotFoundException e) e.printStackTrace(); catch (IOException e) e.printStackTrace(); 截图3、统计一个文本文件中单词的个数。文本文件的名字从命令行中获得。代码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("文本文件中单词的个数为："+stringTokenizer.countTokens(); 结果截图第七章 Java图形用户界面1、阅读下面的程序，回答问题。 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(); 画图表示程序运行后的图形界面。如果程序通过实现某个接口处理按钮的动作事件，则该接口名为何？接口中的方法头声明如何？答：实现的接口是ActionListener，该接口的方法声明是public void actionPerformed(ActionEvent e)2、编写一个简单的计算器，要求图形用户界面如下图所示。代码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. 编程题：

21、请编写一个简单的用户登录程序。要求使用图形用户界面，* 用户名和密码假定均为java，且密码输入时全部显示为星号（*）。 */代码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("宋体",Font.PLAIN,30);

22、 frame.setFont(font); frame.setLayout(new BorderLayout(); JPanel paneltop = new JPanel(); paneltop.add(new JLabel("用户登陆",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("用户名

24、："); final JTextField text1 = new JTextField("",10); panel_11.add(text1); panel_12.add(new JLabel("用户密码："); final JPasswordField text2 = new JPasswordField("",10); text2.setEchoChar('*'); panel_12.add(text2); JButton b=new JButton("确定"); 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("宋体",Font.BOLD,70); dialog.setFont(font1); if(text1.getText().equalsIgnoreCase("java")&

26、&String.valueOf(text2.getPassword().equals("java") dialog.add(new JLabel("登陆成功！",JLabel.CENTER); / new MyCalculator(); else dialog.add(new JLabel("密码或用户名错误！",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(" "); 结果截图第八章 Java多线程技术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;); 下面描述正确的是：（B）单选A) 通过编译和运行但是没有任何输出。B) 通过编译，运行后输出"Running"C) 编译出错，没有线程可供运行D) 编译出错，没有权限使用Thread2、 编写程序，启动1000个线程，每个线程给初值为0的变量sum加1。（提示，需要通过引用传递，将sum传递给每个线程，为了能够进行引用传递，需要定义一个Integer包装对象来保存sum）。代码public class Borley extends Threadpublic static void main(String argv)/通过Integer包装对象sumInteg

29、er sum = new Integer(0);/循环1000次，开启1000个线程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);截图3、利用多线程技术模拟龟兔赛跑的场面。提示：先设计一个线程类模拟两个参与赛跑的选手的行为；然后创建该类的两个对象分别代表乌龟和兔子；让兔子跑快些，但在路上睡眠休息时间长

30、些，而乌龟跑慢些却不休息；当某个选手到达终点时其线程运行结束；二个选手均到达终点时，显示并祝贺获胜选手，然后主线程结束。代码Import java.util.Date;public class xiancheng extends Thread private int tortoise_walk = 0; / 乌龟已跑长度存放变量 private int rabbit_walk = 0; / 兔子已跑长度存放变量 private int finish = 1000; / 终点 private volatile boolean hasWinner = false;/ 胜利者诞生 /* class

31、Tortoise_Run implements Runnable public void run() try while (!hasWinner) if (tortoise_walk % 100 = 0 && (tortoise_walk != 0|tortoise_walk>=finish) /乌龟每100米休息500毫秒 Thread.sleep(500); tortoise_walk+; System.out.println("乌龟已跑"+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