Java语言培训教案.ppt

1、第一章 Java语言概述,华中科技大学IBM技术中心 2008,华中科技大学IBM技术中心,HUST ,华中科技大学IBM技术中心,HUST public int x, y; /constructor public Spot() x = -1; y = -1; size = 1; /methods for access to the size instance variable public void setSize(int newSize) if (newSize = 0) size = newSize; public int getSize() return size; ,华中科技大学IB

2、M技术中心,HUST . spot = new Spot();,华中科技大学IBM技术中心,HUST g2d.fillRect(0, 0, getWidth() - 1, getHeight() - 1);,华中科技大学IBM技术中心,HUST spot.setSize(RADIUS); spot.x = event.getX(); spot.y = event.getY(); repaint(); public void mouseClicked(MouseEvent event) public void mouseReleased(MouseEvent event) public void

3、 mouseEntered(MouseEvent event) public void mouseExited(MouseEvent event) ,欢迎提问,Question !,第三章 Java语言基础,华中科技大学IBM技术中心,华中科技大学IBM技术中心,HUST int i; double pi = 3.1415926; String name;,华中科技大学IBM技术中心,HUST boolean b = 1;,原始类型,华中科技大学IBM技术中心,HUST ,华中科技大学IBM技术中心,HUST if ( i 0) int i = 20; System.out.println(“

4、The value of i = ” + i); System.out.println(“The value of i = ” + i);,华中科技大学IBM技术中心,HUST ,final int blankfinal; . . . blankfinal = 0;,华中科技大学IBM技术中心,HUST Rectangle rect_one = new Rectangle(origin_one, 100, 200); Rectangle rect_two = new Rectangle(50, 100); / 显示rect_one的宽、高以及面积 System.out.println(Widt

5、h of rect_one: + rect_one.width); System.out.println(Height of rect_one: + rect_one.height); System.out.println(Area of rect_one: + rect_one.area(); rect_two.origin = origin_one; /设置rect_two的位置 / 显示rect_two的位置 System.out.println(X Position of rect_two: + rect_two.origin.x); System.out.println(Y Posi

6、tion of rect_two: + rect_two.origin.y); / 移动rect_two并且显示它的新位置 rect_two.move(40, 72); System.out.println(X Position of rect_two: + rect_two.origin.x); System.out.println(Y Position of rect_two: + rect_two.origin.y); ,华中科技大学IBM技术中心,HUST public int y = 0; public Point(int x, int y) this.x = x; this.y =

7、 y; ,Point origin_one = new Point(23, 94);,华中科技大学IBM技术中心,HUST Point origin_two = new Point(23, 94);,Point origin_one = new Point(23, 94); Point origin_two =origin_two;,华中科技大学IBM技术中心,HUST public int height = 0; public Point origin; public Rectangle() origin = new Point(0, 0); public Rectangle(Point p

8、) origin = p; public Rectangle(int w, int h) this(new Point(0, 0), w, h); public Rectangle(Point p, int w, int h) origin = p; width = w; height = h; . ,一个类可以包含多个构造器，这种情况成为构造器的重载 同一个类中的多个构造器通过参数的数目及类型的不同来区分,华中科技大学IBM技术中心,HUST static int share_data; class Demo ABCD a,b,c,d; /实例化 ,华中科技大学IBM技术中心,HUST Sy

9、stem.out.println(Height of rect_one: + rect_one.height); int height=new Rectangle().height;,华中科技大学IBM技术中心,HUST 或者 objectReference.methodName();,System.out.println(Area of rect_one: + rect_one.area(); rect_two.move(40, 72); int areaOfRectangle = new Rectangle(100, 50).area();,华中科技大学IBM技术中心,HUST / 超出对

10、象作用域 ,引用变量引用了其它对象或引用了空对象 StringBuffer s = new StringBuffer(“test1”); s = new StringBuffer(“test2”); / 引用了新的对象 s = null; / 引用为空,华中科技大学IBM技术中心,HUST myRect.width = 40; myRect.height = 50; System.out.println(myRects area is + myRect.area(); ,华中科技大学IBM技术中心,HUST Rectangle rectangle = new Rectangle(point,

11、20, 20); point = null;,华中科技大学IBM技术中心,HUST Character a2 = new Character(a); Character b = new Character(b); int difference = pareTo(b); if (difference = 0) System.out.println(a is equal to b.); else if (difference 0) System.out.println(a is greater than b.); System.out.println(a is + (a.equals(a2) ?

12、equal : not equal)+ to a2.); System.out.println(The character + a.toString() + is + (Character.isUpperCase(a.charValue() ? upper : lower)+ case.); ,程序的输出： a is less than b. a is equal to a2. The character a is lowercase.,华中科技大学IBM技术中心,HUST Character b = new Character(a);,下列boolean表达式的值是true还是false?

13、（1）pareTo(b)=0 （2）a.equals(b) （3）a=b,华中科技大学IBM技术中心,HUST 此外，也可根据String类的构造函数创建String对象： String name = new String(“Petter”); 对于程序任何位置出现的双引号标记的字符串，系统都会自动创建一个String对象。 可通过String对象的方法对字符串进行操作,华中科技大学IBM技术中心,HUST s=s+“defg; System.out.println(s); ,程序运行结果是abc还是abcdefg?,华中科技大学IBM技术中心,HUST str = str + “ 当修改操作

14、频繁，或字符串的值很大时，会额外分配大量内存 因此，Java语言引入了一个StringBuffer类，用来表示内容可以扩充和修改字符串对象,华中科技大学IBM技术中心,HUST StringBuffer dest = new StringBuffer(s);,华中科技大学IBM技术中心,HUST int len = palindrome.length();,华中科技大学IBM技术中心,HUST char aChar = anotherPalindrome.charAt(9);,华中科技大学IBM技术中心,HUST String roar = anotherPalindrome.substrin

15、g(11, 15);,华中科技大学IBM技术中心,HUST private char pathSeparator, extensionSeparator; public Filename(String str, char sep, char ext) fullPath = str; pathSeparator = sep; extensionSeparator = ext; public String extension() int dot = fullPath.lastIndexOf(extensionSeparator); return fullPath.substring(dot + 1

16、); public String filename() int dot = fullPath.lastIndexOf(extensionSeparator); int sep = fullPath.lastIndexOf(pathSeparator); return fullPath.substring(sep + 1, dot); public String path() int sep = fullPath.lastIndexOf(pathSeparator); return fullPath.substring(0, sep); ,华中科技大学IBM技术中心,HUST System.ou

17、t.println(Extension = + myHomePage.extension(); System.out.println(Filename = + myHomePage.filename(); System.out.println(Path = + myHomePage.path(); ,程序输出： Extension = html Filename = index Path = /home/mem,华中科技大学IBM技术中心,HUST Float floatTwo = Float.valueOf(1.0); Double doubleOne = new Double(1.0);

18、int difference = floatOpareTo(floatTwo); if (difference = 0) System.out.println(floatOne is equal to floatTwo.); else if (difference 0) System.out.println(floatOne is greater than floatTwo.); System.out.println(floatOne is “ +(floatOne.equals(doubleOne) ? equal : not equal) + to doubleOne.); ,floatO

19、ne is equal to oneAgain. floatOne is not equal to doubleOne.,华中科技大学IBM技术中心,HUST anArray = new int10; for (int i = 0; i anArray.length; i+) anArrayi = i; System.out.print(anArrayi + ); System.out.println(); ,华中科技大学IBM技术中心,HUST for (int i = 0; i anArray.length; i+) System.out.println(anArrayi); ,华中科技大

20、学IBM技术中心,HUST aMatrix1 = new int5; aMatrix2 = new int10;,华中科技大学IBM技术中心,HUST char copyTo = new char7; System.arraycopy(copyFrom, 2, copyTo, 0, 7); System.out.println(new String(copyTo); ,华中科技大学IBM技术中心,HUST for (int i = 0; i stringBuffers.length; i +) stringBuffersi.append(StringBuffer at index + i);

21、,欢迎提问,Question !,第六章 接口和包,华中科技大学IBM技术中心,华中科技大学IBM技术中心,HUST ,public interface MyInterface int MAXSIZE = 1024; public abstract myMethod(String name); ,华中科技大学IBM技术中心,HUST 声明接口也需要给出访问控制符; 接口具有继承性,通过关键字extends声明该新接口是某父接口的派生接口;一个接口可以有多个父接口，它们之间用逗号分隔，形成父接口列表。,华中科技大学IBM技术中心,HUST 系统默认:接口中的所有属性都是public， stati

22、c和final (公共，静态和最终); 系统默认:接口中的所有方法都是public和 abstract (公共和抽象); 接口中方法的方法体可用Java语言书写,也可用其它语言书写(加native修饰)。,华中科技大学IBM技术中心,HUST 如果实现某个接口的类不是abstract的抽象类，则在类的定义部分必须为所有抽象方法定义具体方法体，方法头部分应该与接口中的定义完全一致;,华中科技大学IBM技术中心,HUST 一个类在实现某个接口的抽象方法时，必须使用完全相同的方法声明。 接口的抽象方法访问修饰符为public,所以,类在实现方法时必须使用修饰符public，否则，系统将警告;因为缩小

23、了接口中定义的方法的访问控制范围。,华中科技大学IBM技术中心,HUST final String oracleTicker = ORCL; final String ciscoTicker = CSCO; void valueChanged(String tickerSymbol, double newValue); void currentValue(String tickerSymbol, double newValue); ,华中科技大学IBM技术中心,HUST ,华中科技大学IBM技术中心,HUST ,华中科技大学IBM技术中心,HUST 该语句是将当前类置于包cardclasses

24、s中，需要在当前文件夹下创建一个名为cardclasses的子文件夹。 再例如：package cardsystem.cardclasses; 该语句将当前类置于cardsystem.cardclasses中，需要在当前文件夹下创建子文件cardsystem并在 cardsystem下再创建的子文件cardclasses，当前类存放在这个文件夹里。,华中科技大学IBM技术中心,HUST Vector vc = new Vector();,华中科技大学IBM技术中心,HUST Vector vc = new Vector(); 消除名称的二义性 使用成员的限定名； 使用环境变量 classpat

25、h set classpath= javac classpath MyClass.java java classpath MyClass,华中科技大学IBM技术中心,HUST 这样，我们在使用java.util包中的任何类时，就可以直接使用简单类名。需要注意的是，import语句要么导入一个类，要么导入一个完整包。不能使用通配符标记包的子集或多个包，下面三条语句均无法通过编译： import java.applet.A*; import java.*.*; import java.*.io;,华中科技大学IBM技术中心,HUST In Server.java add: package myga

26、me.server;: In Utilities.java add: package mygame.shared;,华中科技大学IBM技术中心,HUST public static void main (String args) ExampleOfException eoe = new ExampleOfException(); eoe.methodA(); System.out.println(Program finished.); void methodA() methodB(); void methodB() methodC(); void methodC() for (int i=0;

27、 i4; i+) System.out.println (linesi); ,The first line The second line The last line Exception in thread main java.lang.ArrayIndexOutOfBoundsException: 3 at ExampleOfException.methodC(ExampleOfException.java:16) at ExampleOfException.methodB(ExampleOfException.java:12) at ExampleOfException.methodA(E

28、xampleOfException.java:9) at ExampleOfException.main(ExampleOfException.java:6),华中科技大学IBM技术中心,HUST ,华中科技大学IBM技术中心,HUST public static void main (String args) ExampleOfException eoe = new ExampleOfException(); eoe.methodA(); System.out.println(Program finished.); . void methodC() for (int i=0; i4; i+)

29、 try System.out.println (linesi); catch (ArrayIndexOutOfBoundsException e) System.out.println(Re-setting Index Value); ,华中科技大学IBM技术中心,HUST finally return 0; ,华中科技大学IBM技术中心,HUST try if( sel=0 ) System.out.println(no Exception caught); return; else if( sel=1 ) int i=0; int j=4/i; else if( sel=2 ) int

30、iArray=new int4; iArray10=3; ,华中科技大学IBM技术中心,HUST catch( ArrayIndexOutOfBoundsException e ) System.out.println(Catch +e.getMessage(); catch( Exception e ) System.out.println(Will not be executed); finally System.out.println(in Proc finally); public static void main( String args ) Proc( 0 ); Proc( 1 )

31、; Proc( 2 ); ,程序运行结果： - In Situation0 - no Exception caught in Proc finally - In Situation1 - Catch java.lang.ArithmeticException: / by zero in Proc finally - In Situation2 - Catch 10 in Proc finally,华中科技大学IBM技术中心,HUST if(sel=0) System.out.println(no Exception caught); return; else if(sel=1) int iAr

32、ray=new int4; iArray10=3; ,华中科技大学IBM技术中心,HUST Proc(1); catch(ArrayIndexOutOfBoundsException e) System.out.println(Catch +e); finally System.out.println(in Proc finally); ,程序运行结果： - In Situation0 - no Exception caught - In Situation1 - Catch java.lang.ArrayIndexOutOfBoundsException：10 in Proc finally

33、,华中科技大学IBM技术中心,HUST MyException( int a ) detail = a; public String toString( ) return MyException +detail; ,华中科技大学IBM技术中心,HUST if( a10 ) throw new MyException(a); System.out.println(normal exit); public static void main( String args ) try compute( 1 ); compute( 20 ); catch( MyException e ) System.ou

34、t.println(Caught +e); ,程序运行结果： called compute(1)normal exitcalled compute(20)Caught MyException 20,华中科技大学IBM技术中心,HUST if (n1) throw new NumberFormatException(); catch (NumberFormatException e) System.out.println(输入范围错误！); 代码2： int n = InputReader.inputInteger(请输入一个整数); if (n1) System.out.println(输入范

35、围错误！);,代码1采用了异常处理方式；代码2则通过对用户输入的分析避免了异常的使用，提高了代码效率。,华中科技大学IBM技术中心,HUST String line = null; try input = new RandomAccessFile(named, “r”); while (line = input.readLine() != null System.out.println(line); return; finally if (input != null) input.close(); ,第八章 线程,华中科技大学IBM技术中心,华中科技大学IBM技术中心,HUST public

36、PrintThread( String name ) super( name ); sleepTime = (int) ( Math.random() * 5000 ); System.out.println( Name: + getName() + ; sleep: + sleepTime ); public void run() try System.out.println( getName() + going to sleep ); Thread.sleep( sleepTime ); catch ( InterruptedException ie ) System.err.printl

37、n( ie.toString() ); System.out.println( getName() + done sleeping ); ,华中科技大学IBM技术中心,HUST thread1 = new PrintThread( thread1 ); thread2 = new PrintThread( thread2 ); thread3 = new PrintThread( thread3 ); thread4 = new PrintThread( thread4 ); System.out.println( nStarting threads ); thread1.start(); t

38、hread2.start(); thread3.start(); thread4.start(); System.out.println( Threads startedn ); ,华中科技大学IBM技术中心,HUST private int sleepTime; public PrintRunnable( String name ) = name; sleepTime = (int) ( Math.random() * 5000 ); System.out.println( Name: + name + ; sleep: + sleepTime ); public voi

39、d run() try System.out.println( name + going to sleep ); Thread.sleep( sleepTime ); catch ( InterruptedException ie ) System.err.println( ie.toString() ); System.out.println( name + done sleeping ); ,华中科技大学IBM技术中心,HUST thread1 = new PrintRunnable ( thread1 ); thread2 = new PrintRunnable ( thread2 );

40、 thread3 = new PrintRunnable ( thread3 ); thread4 = new PrintRunnable ( thread4 ); System.out.println( nStarting threads ); new Thread(thread1).start(); new Thread(thread2).start(); new Thread(thread3).start(); new Thread(thread4).start(); System.out.println( Threads startedn ); ,华中科技大学IBM技术中心,HUST

41、import java.awt.Graphics; import java.util.Date; public class ClockApplet extends Applet implements Runnable private Thread clockThread = null; public void start() if (clockThread =null) clockThread = new Thread(this); clockThread.start(); public void paint(Graphics g) Date date = new Date(); g.draw

42、String(date.toString(), 5, 10); ,华中科技大学IBM技术中心,HUST try Thread.sleep(1000); catch (InterruptedException e) ,华中科技大学IBM技术中心,HUST 除非更高优先级的抢占CPU，或者,华中科技大学IBM技术中心,HUST public void run() while(true) int i; for(int j=0; j100000; j+) for(int k=0; k1000; k+) i = j + k; if (getPriority()NORM_PRIORITY) System.

43、out.println(getName() + is running.); ,华中科技大学IBM技术中心,HUST PriorityTest test2 = new PriorityTest(Lower priority thread); test2.setPriority(4); test1.start(); test2.start(); 从运行结果上看，低优先级的线程也有执行的机会。,华中科技大学IBM技术中心,HUST public int get() return this.data; public void put(int data) this.data = data; ,华中科技大

44、学IBM技术中心,HUST public Producer(CubbyHole res) this.res = res; public void run() for (int i=0; i10; i+) res.put(i); System.out.println(“Producer put:” + i); try sleep(int)(Math.random()*100); catch (InterruptedException e) ,华中科技大学IBM技术中心,HUST public Consumer(CubbyHole res) this.res = res; public void

45、run() for (int i=0; i10; i+) System.out.println(“Consumer get:” + res.get(); try sleep(int)(Math.random()*100); catch (InterruptedException e) ,华中科技大学IBM技术中心,HUST Producer pro = new Producer(res); Consumer con = new Consumer(res); pro.start(); con.start(); ,华中科技大学IBM技术中心,HUST private boolean getable

46、; public synchronized int get() while (getable = false) try wait(); catch (InterruptedException e) getable = false; notifyAll(); return this.data; ,华中科技大学IBM技术中心,HUST catch (InterruptedException e) this.data = data; getable = true; notifyAll(); ,华中科技大学IBM技术中心,HUST synchronized b() a(); ,华中科技大学IBM技术中

47、心,HUST Thread thread1 = new Thread(myGroup, “thread one”); Thread thread2 = new Thread(myGroup, “thread two”);,华中科技大学IBM技术中心,HUST class Copy private void copy(InputStream in, OutputStream out) throws IOException byte buf = new byte4096; int len = in.read(buf); while (len != -1) out.write(buf, 0, len

48、); len = in.read(buf); public void cat(String fsrc, String fdest) try InputStream in = new FileInputStream(fsrc); OutputStream out = new FileOutputStream(fdest, true); copy(in, out); out.close(); in.close(); catch (IOException ex) System.err.println(ex); ,华中科技大学IBM技术中心,HUST c.cat(“in.dat”,”out.dat”)

49、; ,华中科技大学IBM技术中心,HUST publicclassByteArrayOutputStreamTest publicstaticvoidmain(Stringargs) try ByteArrayOutputStreambaos=newByteArrayOutputStream(); PrintStreamps=newPrintStream(baos); for(inti=0;i1000;i+) ps.println(i+ABCDEFGHIJKLMNOPQRSTUVWXYZ); longstart=System.currentTimeMillis(); FileOutputStr

50、eamfos= newFileOutputStream(ByteArrayOutputStreamTest); baos.writeTo(fos); fos.close(); longstop=System.currentTimeMillis(); System.out.println(timeelapsed(milliseconds)=+(stop-start); catch(FileNotFoundExceptionfnfe) System.out.println(fnfe.getMessage(); catch(IOExceptionioe) System.out.println(ioe

51、.getMessage(); ,华中科技大学IBM技术中心,HUST PipedOutputStream(PipedInputStream pis); 通过各自的connect()方法连接： 在类PipedInputStream中，connect(PipedOutputStream pos); 在类PipedOutputStream中，connect(PipedInputStream pis);,华中科技大学IBM技术中心,HUST PipedInputStream pis = new PipedInputStream(); PipedOutputStream pos = new PipedO

52、utputStream(pis); System.out.println(PipedInputStream); try pos.write(dataA); pos.write(dataB); System.out.println(byte)pis.read(); System.out.println(byte)pis.read(); finally pis.close(); pos.close(); ,华中科技大学IBM技术中心,HUST public class ReadLineTest public static void main(String args) try BufferedRea

53、der br = new BufferedReader(new FileReader(args0); String line = null; int i = 0; while(line = br.readLine() != null) i+; System.out.println(i + : + line); br.close(); catch(Exception e) e.printStackTrace(); ,华中科技大学IBM技术中心,HUST publicclassFileTest publicstaticvoidmain(Stringargs)throwsIOException Ra

54、ndomAccessFileraf=newRandomAccessFile(foo.txt,rw); try Writerout= newOutputStreamWriter(newFileOutputStream(raf.getFD(),UTF-8); out.write(HelloWorld!); out.flush(); raf.seek(6); out.write(Java); out.flush(); finally raf.close(); ,第十章 图形用户界面,华中科技大学IBM技术中心,华中科技大学IBM技术中心,HUST import javax.swing.*; publ

55、ic class GUITest extends JFrame private JLabel label; private JButton button; private JCheckBox checkbox; private JRadioButton rbutton; private JTextField textfield; private JComboBox cbox; private JList list;,华中科技大学IBM技术中心,HUST Container container = getContentPane(); container.setLayout(new FlowLayout(); label = new JLabel(Im JLabel); but