Java2程序设计经典例子

1Java2程序设计1第一章Java程序设计概述例子1：第一个Java程序publicclassHello{publicstaticvoidmain(Stringargs[]){System.out.println(你好，很高兴学习Java);}}例子2：第二个java程序classPeople{intheight;Stringear;voidspeak(Strings){System.out.println(s);}}publicclassA{publicstaticvoidmain(Stringargs[]){Peoplezhubajie;zhubajie=newPeople();zhubajie.height=170;zhubajie.ear=两只大耳朵;System.out.println(身高:+zhubajie.height);System.out.println(zhubajie.ear);zhubajie.speak(师傅，咱们别去西天了，改去月宫吧);}}例子3：Applet程序（由AppletTest.class和AppletTest.html组成）importjava.applet.*;importjava.awt.*;publicclassAppletTestextendsApplet{publicvoidpaint(Graphicsg){g.setColor(Color.red);g.drawString(我一边喝着咖啡，一边学Java呢,5,30);g.setColor(Color.blue);g.drawString(我学得很认真,10,50);}2}//AppletTest.htmlhtmlheadtitleApplettestexample/title/headbodyh1Thisisaappletexample/h1hrappletcode=AppletTest.classwidth=800height=600/applethrahref=AppletTest.javaThesource/a./body/html例子4：Java图形用户界面例子//JavaGUI.javaimportjava.awt.FlowLayout;importjava.awt.event.*;importjavax.swing.JButton;importjavax.swing.JFrame;importjavax.swing.JLabel;importjavax.swing.JTextField;/***@author同步计算输入的各个数的总和与平均值*/publicclassJavaGUIextendsJFrame{privatestaticfinallongserialVersionUID=6515574844960224544L;JTextFieldinput=newJTextField(30);JTextFieldoutput=newJTextField(30);JButtonclose=newJButton(关闭);JButtonreset=newJButton(清空);publicJavaGUI(){setupGUI();}publicvoidsetupGUI(){this.setTitle(计算总和与平均值);this.setLayout(newFlowLayout());this.add(newJLabel(数据));3this.add(input);this.add(newJLabel(结果));this.add(output);this.add(close);this.add(reset);setSize(400,130);input.addKeyListener(newKeyAdapter(){publicvoidkeyReleased(KeyEvente){Stringstr=input.getText();if(str.equals()||str==null){output.setText();}else{Stringnum[]=str.split();intsum=0;doubleavg=0.0;for(inti=0;inum.length;i++){sum+=Integer.parseInt(num[i]);}avg=sum*1.0/num.length;output.setText(Sum=+sum+,Avg=+avg);}}});close.addMouseListener(newMouseAdapter(){publicvoidmouseClicked(MouseEventarg0){System.exit(0);}});reset.addMouseListener(newMouseAdapter(){publicvoidmouseClicked(MouseEventarg0){input.setText();output.setText();}});setVisible(true);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);}publicstaticvoidmain(String[]args){newJavaGUI();}}4第二章Java程序设计技术例子1：字符型变量publicclassCharacterTest{publicstaticvoidmain(Stringargs[]){charchinaWord='你',japanWord='ぁ';intp1=36328,p2=38358;System.out.println(汉字\'你\'在unicode表中的顺序位置:+(int)chinaWord);System.out.println(日语\'ぁ\'在unicode表中的顺序位置:+(int)japanWord);System.out.println(unicode表中第20328位置上的字符是:+(char)p1);System.out.println(unicode表中第12358位置上的字符是:+(char)p2);}}例子2：数据类型转换publicclassDataTypeTest{publicstaticvoidmain(Stringargs[]){intc=2200;longd=8000;floatf;doubleg=123456789.123456789;c=(int)d;f=(float)g;//导致精度的损失.System.out.print(c=+c);System.out.println(d=+d);System.out.println(f=+f);System.out.println(g=+g);}}例子3：使用异或对字符进行加密和解密classXORTest{publicstaticvoidmain(Stringargs[]){chara1='十',a2='点',a3='进',a4='攻';charsecret='8';a1=(char)(a1^secret);a2=(char)(a2^secret);图2.2基本数据的转换与输出5a3=(char)(a3^secret);a4=(char)(a4^secret);System.out.println(密文:+a1+a2+a3+a4);a1=(char)(a1^secret);a2=(char)(a2^secret);a3=(char)(a3^secret);a4=(char)(a4^secret);System.out.println(原文:+a1+a2+a3+a4);}}例子4：短路逻辑或(||)和位运算(|)的区别classOrTest{publicstaticvoidmain(Stringargs[]){intx,y=10;if(((x=0)==0)||((y=20)==20)){System.out.println(现在y的值是:+y);}inta,b=10;if(((a=0)==0)|((b=20)==20)){System.out.println(现在b的值是:+b);}}}例子5：用if语句实现a、b、c的值按从小到大排序publicclassSortABC{publicstaticvoidmain(Stringargs[]){inta=9,b=5,c=7,t;if(ab){t=a;a=b;b=t;}if(ac){t=a;a=c;c=t;}if(bc){t=b;b=c;c=t;}System.out.println(a=+a+,b=+b+,c=+c);}}6例子6：用if语句判断给定的成绩是否及格publicclassScore{publicstaticvoidmain(Stringargs[]){intmath=65,english=85;if(math=60){System.out.println(数学及格了);}else{System.out.println(数学不及格);}if(english90){System.out.println(英语是优);}else{System.out.println(英语不是优);}System.out.println(我在学习控制语句);}}例子7：switch语句的使用，当主程序执行时，如果第一个命令行参数的首字符分别是数字、小写字母及大写字母时，系统会显示这个首字符。如果输入的是非数字或字母，则显示不是数字或字母。classEx2_07{publicstaticvoidmain(String[]args){charch=args[0].charAt(0);switch(ch){case'0':case'1':case'2':case'3':case'4':case'5':case'6':case'7':case'8':case'9':System.out.println(Thecharacterisdigit+ch);break;case'a':case'b':case'c':case'd':case'e':case'f':case'g':case'h':case'i':case'j':case'k':case'l':case'm':case'n':case'o':case'p':case'q':case'r':case's':case't':case'u':case'v':case'w':case'x':case'y':case'z':System.out.println(Thecharacterislowercaseletter+ch);break;case'A':case'B':case'C':case'D':case'E':case'F':case'G':case'H':case'I':case'J':case'K':case'L':case'M':case'N':case'O':case'P':case'Q':case'R':case'S':case'T':case'U':7case'V':case'W':case'X':case'Y':case'Z':System.out.println(Thecharacterisuppercaseletter+ch);break;default:System.out.println(Thecharacter+ch+isneitheradigitnoraletter.);}}}例子8：使用for循环，计算5+55+555+。。。的前10项的和publicclassExample3_6{publicstaticvoidmain(Stringargs[]){longsum=0,a=5,item=a,n=10,i=1;for(i=1;i=n;i++){sum=sum+item;item=item*10+a;}System.out.println(