Jaa语言程序设计编程练习题答案

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Java语言程序设并Java语言程序设讦

基础篇进阶篇

JAVA

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/

/厂网

［编程练习题答案］Java语言程序设计（基础篇K选阶篇）第13、14、

15、24、25、26、28、29、30、31章部分习题答案，奇教题和部分

双教题是我自己做的，在此和大彖分享「_人〜

上Chapter13Exercise13.2/13.8/13.11

importjavax.swing.*;

importjava.awt.*;

publicclassExercis㊀132extendsJFrame{

//Createtwobuttons

privateOvalButtonjbtOk=newOvalButton(n0Kn);

privateOvalButtonjbtCancel=newOvalButton("Cancel**);

/**Defaultconstructor*/

publicExercisel3_2(){

//Setthewindowtitle

setTitle(nExercisel3_2");

//SetFlowLayoutmanagertoarrangethecomponents

//insidetheframe

getContentPane().setLayout(newFlowLayout());

//Addbuttonstotheframe

getContentPane().add(jbtOk);

getContentPane().add(jbtCancel);

)

/**Mainmethod*/

publicstaticvoidmain(String[]args){

Exercisel3_2frame=newExercisel3_2();

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.pack();

frame.setVisible(true);

}

)

classOvalButtonextendsJButton{

publicOvalButton(){

)

publicOvalButton(Stringtext){

super(text);

)

protectedvoidpaintComponent(Graphicsg){

//Drawanoval

super.paintcomponent(g);

g.drawOval(5,5,getWidth()-10,getHeight()-10);

)

/**Overridegetmethodforpreferredsize★/

publicDimensiongetPreferredSize(){

returnnewDimension(100f50);

)

/**Overridegetmethodforminimumsize*/

publicDimensiongetMinimumSize(){

returnnewDimension(100,50);

importjava.awt.*;

importjavax.swing.*;

publicclassExercisei38extendsJFrame{

publicstaticvoidmain(String[]args){

JFrameframe=newExercisel3_8();

frame.setSize(300z300);

frame.setTitle(nExercisel3_8");

frame.setDefaultCloseoperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

)

publicExercisel3_8(){

getContentPane().add(newOctagonPanel());

)

}

classOctagonPanelextendsJPanel{

protectedvoidpaintComponent(Graphicsg){

super.paintComponent(g);

intxCenter=getWidth()/2;

intyCenter=getHeight()/2;

intradius=

(int)(Math.min(getWidth(),getHeight())*0.4);

//CreateaPolygonobject

Polygonpolygon=newPolygon();

//Addpointstothepolygon

polygon.addPoint(xCenter+radius,yCenter);

polygon.addPoint((int)(xCenter+radius*Math.cos(2*Math.PI/8)),

(int)(yCenter-radius*Math.sin(2*Math.PI/8)));

polygon.addPoint((int)(xCenter+radius*Math.cos(22*Math.PH/

8))，

(int)(yCenter-radius*Math.sin(2*2*Math.PI/8)));

polygon.addPoint((int)(xCenter+radius*Math.cos(3*2*Math.PI

/8)),

(int)(yCenter-radius*Math.sin(3*2*Math.PI/8)));

polygon.addPoint((int)(xCenter+radius*Math.cos(4*2*Math.PI

/8)),

(int)(yCenter-radius*Math.sin(4*2*Math.PI/8)));

polygon.addPoint((int)(xCenter+radius*Math.cos(5*2*Math.PI

/8)),

(int)(yCenter-radius*Math.sin(5*2*Math.PI/8)));

polygon.addPoint((int)(xCenter+radius*Math.cos(6*2*Math.PT

/8)),

(int)(yCenter-radius*Math.sin(6*2*Math.PI/8)))；

polygon.addPoint((int)(xCenter+radius*Math.cos(7*2*Math.PT

/8)),

(int)(yCenter-radius*Math.sin(7*2*Math.PI/8)));

//Drawthepolygon

g.drawPolygon(polygon);

)

importjavax.swing.*;

importjava.awt.*;

publicclassExercisei3」1extendsJFrame{

publicExercisel3_ll(){

add(newSquareFunction());

)

/**

*@paramargs

*/

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

Exercisel3_l1frame=newExercisel3_ll();

frame.setTitle(MExercisel3.11n);

frame.setSize(300,200);

frame.setLocationRelativeTo(null);

frame.setDefauItCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

classSquareFunctionextendsJPanel{

publicSquareFunction(){

protectedvoidpaintComponent(Graphicsg){

super.paintComponent(g);

g.drawLine(10,this.getHeight()-20,this.getWidth()-10,

this.getHeight()-20);

g.drawLine(this.getWidth()-30,this.getHeight()-15,

this.getWidth()-10zthis.getHeight()-20);

g,drawLine(this.getWidth()-30,this.getHeight()-25,

this.getWidth()TO,this.getHeight()-20);

nn

g.drawstring(Xzthis.getWidth()-10,this.getHeight()-30);

g.drawLine(this.getWidth()/2,20,this.getWidth{)/2,

this.getHeight()-5);

g.drawLine(this.getWidth()/2Z20,this.getWidth()/2-5z35);

g.drawLine(this.getWidth()/2r20,this.getWidth()/2+5,35);

nn

g.drawstring(Yzthis.getWidth()/2+10,30);

Polygonp=newPolygon();

doublescaleFactor=0.01;

for(intx=-100;x<=100;x++){

p.addPoint(x+this.getWidth()/2,

this.getHeight()-20-(int)(scaleFactor*x*x));

)

g.drawPolyline(p.xpoints,p.ypoints,p.npoints);

)

}

packagechapterl4;

importjavax.swing.*;

importjava.awt.event.*;

importjava.awt.*;

publicclassExercisel44extendsJFrame{

publicExercisel4_4(){

MousePositionp=newMousePosition();

add(p);

}

/**

*@paramargs

*/

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

Exercisel4_4frame=newExercisel4_4();

frame.setTitle("Exercise14.4n);

frame.setSize(300,200);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setLocationRelativeTo(null);

frame.setVisible(true);

)

staticclassMousePositionextendsJPanel{

privateStringposition=

privateintx;

privateinty;

publicMousePosition(){

addMouseListener(newMouseAdapter(){

publicvoidmousePressed(MouseEvente){

x=e.getX();

y=e.getY();

position=+x++y+

repaint();

)

publicvoidmouseReleased(MouseEvente){

x=e.getX();

y=e.getY()；

position=n*';

repaint();

}

publicvoidmouseClicked(MouseEvente){

x=e.getX();

y=e.getY();

position=+x++y+

repaint();

)

})；

)

protectedvoidpaintComponent(Graphicsg){

super.paintComponent(g);

g.drawstring(position,x,y);

importjavax.swing.*;

importjava.awt.*;

importjava.awt.event.*;

pub」icclassExercisel48extendsJFrame{

privateCharacterPanelcharacterPansel=newCharacterPanel();

publicExercisel4_8(){

add(characterPansel);

characterPansel.setFocusable(true);

*@paramargs

*/

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

JFrameframe=newExercisel4_8();

frame.setTitle(”Exercise14.8n);

frame.setsize(300z200);

frame.setLocationRelativeTo(null);

frame.setDefaultCloseOperation(JFrame.EXIT_<J_CLOSE);

frame.setVisible(true);

staticclassCharacterPanelextendsJPanel{

privateintx=5;

privateinty=10;

privatecharcharacter;

publicCharacterPanel(){

addKeyListener(newKeyAdapter(){

publicvoidkeyTyped(KeyEvente){

character=e.getKeyChar();

repaint();

}

))；

addMouseListener(newMouseAdapter(){

publicvoidmouseClicked(MouseEvente)

x=e.getX();

y=e.getY();

repaint();

)

})；

}

protectedvoidpaintComponent(Graphicsg){

super.paintComponent(g);

//g.setFont(newFont("TimesRoman**zFont.PLAIN,24));

g.drawstring(nn+character,x,y);

importjavax.swing.*;

importjava.awt.*;

importjava.awt.event.*;

publicclassExercisel49extendsJFrame{

privateDrawLinesPaneldrawLinesPanel=newDrawLinesPanel();

publicExercisel4_9(){

add(drawLinesPanel);

drawLinesPanel.setFocusable(true);

)

/**

*@paramargs

*/

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

Exercisel4_9frame=newExercisel4_9();

frame.setTitle(**Exercisel4.9**);

frame.setSize(300,200);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setLocationRelativeTo(null)；

frame.setVisible(true);

)

staticclassDrawLinesPanelextendsJPanel{

privateintx,y;

privatePolygonpolygon=newPolygon();

publicDrawLinesPanel(){

polygon.addPoint(x,y);

addKeyListener(newKeyAdapter(){

publicvoidkeyPressed(KeyEvente){

switch(e.getKeyCode()){

caseKeyEvent.VK_UP:

y_=10；

polygon.addPoint(x,y);

break;

caseKeyEvent.VK_DOWN:

y+=10;

polygon.addPoint(xzy);

break;

caseKeyEvent.VK_LEFT:

x-=10;

polygon.addPoint(xzy);

break;

caseKeyEvent.VK_RIGHT:

x+=10;

polygon.addPoint(xzy);

break;

)

repaint();

)

})；

}

protectedvoidpaintComponent(Graphicsg){

super.paintComponent(g);

Polygonp=newPolygon();

intxCenter=getWidth()/2;

intyCenter=getHeight()/2;

for(inti=0;i<polygon.npoints;i++){

p.addPoint(polygon.xpoints[i]+

xCenter,polygon.ypoints[i]+yCenter);

g.drawPolyline(p.xpoints,p.ypoints,p.npoints);

)

}

}

+Chapter15Exercise15.4/15.6/15.7

importjava.awt.*;

importjava.awt.event.*;

importjavax.swing.*;

publicclassExercise!54extendsJFrame{

protectedJButtonjbtAdd,jbtSubtract,jbtMultiply,jbtDivide;

protectedJTextFieldjtfNuml,jtfNum2,jtfResult;

protecteddoublexzy,result;

publicExercisel5_4(){

setLayout(newBorderLayout());

JPaneljpIO=newJPanel();

jpIO.setLayout(newFlowLayout());

add(jpIOfBorderLayout.CENTER);

jpIO.add(newJLabel("Number1n));

jpIO.add(jtfNuml=newJTextField(4));

jpIO.add(newJLabel("Number2n));

jpIO.add(jtfNum2=newJTextField(4));

jpIO.add(newJLabel(nResultn));

jpIO.add(jtfResult=newJTextField(8));

jtfNuml.setHorizontalAlignment(JTextField.RIGHT);

jtfNum2.setHorizontalAlignment(JTextField.RIGHT);

,setHorizontalAlignment(JTextField.RIGHT)

jtfResult.setEditable(false);

JPaneljpButtons=newJPanel();

jpButtons.setLayout(newFlowLayout());

add(jpButtons,BorderLayout.SOUTH);

jpButtons.add(jbtAdd=newJButton("Add”))；

jpButtons.add(jbtSubtract=newJButton(''Subtractn;

jpButtons.add(jbtMultiply=newJButton(*'Multiply**));

jpButtons.add(jbtDivide=newJButton("Divide”))；

ButtonGroupgroup=newButtonGroup();

group.add(jbtAdd);

group.add(jbtSubtract);

group.add(jbtMultiply);

group.add(jbtDivide);

jbtAdd.setMnemonic(1Af)；

jbtSubtract.setMnemonic('S1);

jbtMultiply.setMnemonic('M*);

jbtDivide.setMnemonic(*D*);

jbtAdd.addActionListener(newActionListener(){

publicvoidactionPerformed(ActionEvente){

x=Double.parseDouble(jtfNuml.getText());

y=Double.parseDouble(jtfNum2.getText());

result=add(xzy);

jtfResult.setText(n*'+(float)result);

}

})；

jbtSubtract.addActionListener(newActionListener(){

publicvoidactionPerformed(ActionEvente){

x=Double.parseDouble(jtfNuml.getText());

y=Double.parseDouble(jtfNum2.getText());

result=subtract(x,y);

jtfResult.setText(n*'+(float)result);

)

})；

jbtMultiply.addActionListener(newActionListener(){

publicvoidactionPerformed(ActionEvente){

x=Double,parseDouble(jtfNuml.getText());

y=Double.parseDouble(jtfNum2.getText());

result=multiply(xzy);

jtfResuIt.setText(*'n+(float)result);

}

})；

jbtDivide.addActionListener(newActionListener(){

publicvoidactionPerformed(ActionEvente){

x=Double.parseDouble(jtfNuml.getText());

V=Double.parseDouble(jtfNum2.getText());

result=divide(x,y);

jtfResult.setText(*'*'+(float)result);

}

})；

}

publicdoubleadd(doublex,doubley){

returnx+y;

)

publicdoublesubtract(doublex,doubley){

returnx-y;

)

publicdoublemultiply(doublex,doubley){

returnx*y;

)

publicdoubledivide(doublex,doubley){

returnx/y;

}

*@paramargs

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

Exercisel5_4frame=newExercisel5_4();

frame.pack();

frame.setLocationRelativeTo(null);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setTitle(nExercisel5.4n);

frame.setVisible(true);

}

}

importjava.awt.*;

importjava.awt.event.*;

importjavax.swing.*;

publicclassExercisel56extendsJFrame{

privatedoublefutureValuezinvestmentAmountzannualInterestRater

years;

protectedJLabeljIbFutureValue,jIblnvestmentAmountr

jlbAnnualInterestRate,jlbYears;

protectedJTextFieldjtfFutureValue,jtfInvestmentAmount,

jtfAnnuaIInterestRate,jtfYears;

protectedJButtonjbtCalculate;

publicExercisel5_6(){

setLayout(newBorderLayout(10z5));

JPaneljpLabels=newJPanel();

JPaneljpTextFields=newJPanel();

JPaneljpButton=newJPanel();

add(jpLabels,BorderLayout.WEST);

add(jpTextFields,BorderLayout.CENTER);

add(jpButton,BorderLayout.SOUTH);

jpLabels.setLayout(newGridLayout(4,1));

jpTextFields.setLayout(newGridLayout(4,1));

jpButton•setLayout(newFlowLayout(FlowLayout.RIGHT));

jpLabels.add(jIblnvestmentAmount=newJLabel('investment

Amount"));

jpLabels.add(jlbYears=newJLabel(nYearsn));

jpLabels.add(jlbAnnualInterestRate=newJLabel("AnnualInterest

Rate**));

jpLabels.add(jlbFutureValue=newJLabel(nFutureValue"));

jpTextFields.add(jtfInvestmentAmount=newJTextField(10));

jpTextFields.add(jtfYears=newJTextField(10));

jpTextFields.add(jtfAnnuallnterestRate=newJTextField(10));

jpTextFields.add(jtfFutureValue=newJTextField(10));

jtfInvestmentAmount.setHorizontalAlignment(JTextField.RIGHT);

jtfYears.setHorizontalAlignment(JTextField.RIGHT);

jtfAnnualInterestRate.setHorizontalAlignment(JTextField.RIGHT);

jtfFutureValue.setHorizontalAlignment(JTextField.RIGHT);

jtfFutureValue.setEditable(false);

jpButton.add(jbtCalculate=newJButton("Calculate*1));

jbtCalculate.setMnemonic(*C*);

jbtCalculate.addActionListener(newActionListener()(

publicvoidactionPerformed(ActionEvente){

investmentAmount=

Double.parseDouble(jtfInvestmentAmount.getText());

annualInterestRate=

Double.parseDouble(jtfAnnuallnterestRate.getText());

years=Double.parseDouble(jtfYears.getText());

futurevalue=investmentAmount*(Math.pouz((1+

annualInterestRate/12/100),(years*12)));

jtfFutureValue.setText(nn+(double)(int)(futurevalue*

100)/100);

)

});

}

/**

*@paramargs

*/

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

Exercisel5_6frame=newExercisel5_6();

frame.setTitle("Exercise15.6n);

frame.pack();

frame.setLocationRelativeTo(null);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

}

}

importjava.awt.*;

importjava.awt.event.*;

importjavax.swing.*;

pub」icclassExercisel57extendsJFrame{

protectedStillClockstillClock=newStillClock();

privateJLabeljlbHour,jlbMinutezjlbSecond;

protectedJTextFieldjtfHour,jtfMinute,jtfSecond;

privateinthourzminute,second;

publicExercisel5_7(){

setLayout(newBorderLayout());

add(stillClock,BorderLayout.CENTER);

JPaneljp=newJPanel();

add(jp,BorderLayout.SOUTH);

jp.setLayout(newFlowLayout());

jp.add(jlbHour=newJLabel("Hour"));

jp.add(jtfHour=newJTextField(2));

jp.add(jlbMinute=newJLabel("Minute*'))

jp.add(jtfMinute=newJTextField(2));

jp.add(jlbSecond=newJLabel(nSecondn))

jp.add(jtfSecond=newJTextField(2));

jtfHour.addActionListener(newActionListener(){

publicvoidactionPerformed(ActionEvente){

hour=Integer.parselnt(jtfHour.getText());

stillClock.setHour(hour);

}

})；

jtfMinute.addActionListener(newActionListener(){

publicvoidactionPerformed(ActionEvente){

minute=Integer.parselnt(jtfMinute.getText());

stillClock.setMinute(minute);

}

})；

jtfSecond.addActionListener(newActionListener(){

publicvoidactionPerformed(ActionEvente){

second=Integer.parselnt(jtfSecond.getText());

stillClock.setSecond(second);

)

})；

)

/**

*@paramargs

*/

publicstaticvoidmain(String[]args){

//TODO自动生成方法存根

Exercisel5_7frame=newExercisel5_7();

frame.setTitle(nExercisel5.7n);

frame.setSize(300,220);

frame.setLocationRelativeTo(null);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

+Chapter24Exercise24.12

importjava.awt.*;

importjava.awt.event.*

importjavax.swing.*;

pub」icclassExercise2412extendsJAppletimplementsRunnable{

boolean!sStandalone=false;

JProgressBarjProgressBarl=newJProgressBar();

FlowLayoutflowLayout1=newFlowLayout();

Threadthread;

/**Constructtheapplet*/

publicExercise24_12(){

)

/**Initializetheapplet*/

publicvoidinit(){

try(

jblnit();

}

catch(Exceptione){

e.printStackTrace();

)

)

//Componentinitialization

privatevoidjblnit()throwsException{

this.setsize(newDimension(400,300));

this.getContentPane().setLayout(flowLayout1);

this.getContentPane().add(jProgressBar1,null);

thread=newThread(this);

thread.start();

)

publicvoidrun(){

while(true){

try(

Thread.sleep(500);

}

catch(InterruptedExceptionex){}

jProgressBarl.setvalue((int)(jProgressBarl.getMaximum()*

Math.random()));

}

)

/★★Mainmethod*/

publicstaticvoidmain(String[]args){

Exercise24_12applet=newExercise24_12();

applet.isStandalone=true;

JFrameframe=newJFrame();

frame.setTitle(nExercise24_12n);

frame.getContentPane().add(applet,BorderLayout.CENTER);

applet.init();

applet.start();

frame.pack();

Dimensiond=Toolkit.getDefaultToolkit().getScreenSize();

frame.setLocation((d.width-frame.getSize().width)/2,(d.height

-frame.getSize().height)/2);

frame•setVisible(true);

)

//staticinitializerforsettinglook.&feel

static{

try(

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

//UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClass

Name());

)

catch(Exceptione){}

}

)

+Chapter25Exercise25.1/25.10

Exercise25.13S^§S

Exerdse25_1ServerstatedatSatDec1810:34:23CST2010

i_Exe「cise25_l客户流IOI回r5n

Startingthreadfordient1atSatDec1810:34:51CST2010

ClientTshostnameis127.0.01AnnuallnterestRate2.3

ClientTsIPadressisNumberOfYears2提交

AnnualInterestRate2.3NumberOfYears3.0LoanAmount10000.0

MonthlyPayment287.7373239917401LoanAmount10000

TotalPayment10358.543663702643AnnualInterestRate3.3NumberOfYears2.0

-LoanAmount10000.0

Startingthreadfordient2atSatDec1810:35:00CST2010IMonthlyPayment431.14035258423127

Client2'shostnameis

ClientZsIPadressisTotalPayment10347.36846202155

AnnualInterestRate2.3NumberOfYears2.0LoanAmount10000.0

MonthlyPayment426.72257743934637

importjava.io.*;

import.*;

importjava.util.*;

importjava.awt.*;

importjavax.swing.*;

pub」icclassExercise25lServerextendsJFrame{

privateJTextAreajta=newJTextArea();

/*

privateObjectOutputStreamtoClient;

privateObjectInputStreamfromClient;

*/

publicExercise25_lServer(){

setLayout(newBorderLayout());

add(newJScrollPane(jta)rBorderLayout.CENTER);

jta.setEditable(false);

jta.setLineWrap(true);

jta.setWrapStyleWord(true);

setTitle(nExercise25.1月艮务器”);

setSize(420,300);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setVisible(true);

try{

ServerSocketserversocket=newServerSocket(8000);

jta.append(nExercise25_lServerstatedat*'+newDate()+

〃\n”);

intclient=0;

while(true){

//监听连接，等待新的连接请求

Socketsocket=serversocket.accept();

client++;

jta.append(**\nStartingthreadforclient"+client+”at

"+newDate()+*'\nn);

//获取客户域名及工P地址

InetAddressinetAddress=socket.getInetAddress();

jta.append(nClient*'+client+**'shostnameis**+

inetAddress.getHostName()+n\nn);

jta.append(**Client*'+client+*'*sIPadressis*'+

inetAddress.getHostAddress()+*'\nn);

HandleAClienttask.=newHandleAClient(socket);

newThread(task).start();

}catch(lOExceptionex){

System.err.printIn(ex);

)

)

/**

*@paramargs

*/

publicstaticvoidmain(String[]args){

//TODOAuto-generatedmethodstub

newExercise25_lServer();

}

/**内部类

*定义线程类来处理新的连接*/

classHandleAClientimplementsRunnable{

privateSocketsocket;

publicHandleAClient(Socketsocket){

this.socket=socket;

)

©Override

publicvoidrun(){

try(

ObjectInputStreaminputFromClient=new

ObjectInputStream