Thinking in Java第四版Acess部分答案Word文档格式.docx
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*privatevoidshowd（）{System.out.println（d）;
}
*}
packageaccess;
//runcommandjavaaccess.AccessTest
publicclassAccessTest{
publicstaticvoidmain（String[]args）{
FourWaysfw=newFourWays（）;
fw.showa（）;
fw.showb（）;
fw.showc（）;
fw.a=10;
fw.b=20;
fw.c=30;
//!
fw.showd（）;
//privateaccess,compilercan'
ttouch
}
（NO.2）//access/Collision.java
//TIJ4ChapterAccess,Exercise2,page217
/*Takethecodefragmentsinthissectionandturnthemintoaprogramand
*verifythatcollisionsdooccur.
importnet.mindview.simple.*;
importjava.util.*;
publicclassCollision{
//Vectorv=newVector（）;
//ambiquouscollision
net.mindview.simple.Vectorv1=newnet.mindview.simple.Vector（）;
java.util.Vectorv2=newjava.util.Vector（）;
（NO.3）//access/ConnectionManager.java
//TIJ4ChapterAccess,Exercise8,page233
/*FollowingtheformoftheexampleLunch.java,createaclasscalled
*ConnectionManagerthatmanagesafixedarrayofConnectionobjects.Theclient
*programmermustnotbeabletoexplicitlycreateConnectionobjects,butcan
*onlygetthemviaastaticmethodinConnectionManager.WhenConnectionManager
*runsoutofobjects,itreturnsanullreference.Testtheclassesinmain（）.*/
classConnection{
privatestaticintcount=0;
privateinti=0;
privateConnection（）{System.out.println（"
Connection（）"
//Allowcreationviastaticmethod:
staticConnectionmakeConnection（）{
count++;
returnnewConnection（）;
publicstaticinthowMany（）{returncount;
publicStringtoString（）{
return（"
Connection"
+count）;
publicclassConnectionManager{
staticinthowManyLeft=3;
staticConnection[]ca=newConnection[3];
{
for（Connectionx:
ca）
x=Connection.makeConnection（）;
publicstaticConnectiongetConnection（）{
if（howManyLeft>
0）
returnca[--howManyLeft];
else{
System.out.println（"
Nomoreconnections"
returnnull;
}
publicstaticvoidmain（String[]args）{
ConnectionManagercm=newConnectionManager（）;
System.out.println（cm.howManyLeft）;
cm.getConnection（）;
System.out.println（howManyLeft）;
System.out.println（cm.getConnection（））;
}
（NO.4）//access/cookie2/CookieMonster.java
//TIJ4ChapterAccess,Exercise4,page227
//Showthatprotectedmethodshavepackageaccessbutarenotpublic.
/*IndirectoryCookie2:
*//access/cookie2/Cookie.java
*//Createsalibrary
*packageaccess.cookie2;
*publicclassCookie{
*publicCookie（）{
*System.out.println（"
Cookiecontstructor"
*protectedvoidbite（）{System.out.println（"
bite"
packageaccess.cookie2;
publicclassCookieMonster{
Cookiex=newCookie（）;
x.bite（）;
//packageaccesstoprotectedmethod
（NO.5）//access/debug/Debug.java
//TIJ4ChapterAccess,Exercise3,page220
/*Createtwopackages:
debuganddebugoff,containinganidenticalclasswitha
*debug（）method.ThefirstversiondisplaysitsStringargumenttotheconsole,
*theseconddoesnothing.Useastaticimportlinetoimporttheclassintoatest
*program,anddemonstratetheconditionalcompilationeffect.
/*Indirectoryaccess/debugoff:
*//access/debugoff/Debug.java
*packageaccess.debugoff;
*publicclassDebug{
*publicstaticvoiddebug（Strings）{}
packageaccess.debug;
publicclassDebug{
publicstaticvoiddebug（Strings）{
System.out.println（s）;
（NO.6）//TIJ4chapterAccess,Exercise9,page233
/*Createinaccess/localdirectoryinyourCLASSPATH:
*//access/local/PackagedClass.java
*packageaccess.local;
*classPackagedClass{
*publicPackagedClass（）{
Creatingapackagedclass"
*//Then,inanotherdirectrorycreatethefilebelowandexplainwhycompiler
*generateserror.WouldmakingForeignclasspartofaccess.localchangeanything?
//access/foreign/Foreign.java
packageaccess.foreign;
importaccess.local.*;
publicclassForeign{
PackagedClasspc=newPackagedClass（）;
/*Compilererrorbecause:
PackagedClassinnotpublic,sonoaccessoutsideof
*package.MovingForeigntolocalwouldallowpackageaccesstoPackagedClass.
（NO.7）//MakeWidget.java
//TIJ4ChapterAccess,Exercise7,page230
/*CreatethelibraryaccordingtothecodefragmentsdescribingaccessandWidget.
*CreateaWidgetinaclassthatisnotpartoftheaccesspackage.
/*inaccesspackage:
*//access/Widget.java
*publicclassWidget{
*publicWidget（）{System.out.println（"
Widget（）"
importaccess.*;
publicclassMakeWidget{
Widgetw=newWidget（）;
（NO.8）//access/ProtectedData.java
//TIJ4ChapterAccess,Exercise6,page228
/*Createaclasswithprotecteddata.Createasecondclassinthesamefilewith
*amethodthatmanipulatestheprotecteddatainthefirstclass.
classSomeData{
protectedinta=13;
classDataChanger{
staticvoidchange（SomeDatasd,inti）{sd.a=i;
publicclassProtectedData{
SomeDatax=newSomeData（）;
System.out.println（x.a）;
DataChanger.change（x,99）;
（NO.9）//access/UnpackagedMyClass.java
//TIJ4ChapterAccess,Exercise1,page217
//Createaclassinapackage.Createaninstanceofyourclassoutsideofthatpackage.
/*Inanotherdirectory:
*//access/mypackage/MyPackagedClass.java
*packageaccess.mypackage;
*publicclassMyPackagedClass{
*publicMyPackagedClass（）{System.out.println（"
MyPackagedClass（）"
*}
publicclassUnpackagedMyClass{
access.mypackage.MyPackagedClassm=newaccess.mypackage.MyPackagedClass（）;
//arrays/ArrayOfGenerics10.java
//TIJ4ChapterArrays,Exercise10,page762
//ModifyArrayOfGeneric.javatousecontainersinsteadofarrays.
//Showthatyoucaneliminatethecompile-timewarnings.
publicclassArrayOfGenerics10{
@SuppressWarnings（"
unchecked"
）
List<
List<
String>
>
lls=newArrayList<
（）;
List>
l=newArrayList<
//lls=（List<
）l;
//error:
inconvertibletypes
lls.add（newArrayList<
（））;
Object>
lo=newArrayList<
//lo=lls;
incompatibletypes
//Compile-timewarningeliminated:
BerylliumSphere>
llb=
newArrayList<
for（inti=0;
i<
10;
i++）{
llb.add（newArrayList<
for（intj=0;
j<
2;
j++）
llb.get（i）.add（newBerylliumSphere（））;
System.out.println（llb）;
//arrays/ContainerComparison15.java
//TIJ4ChapterArrays,Exercise15,page775
//ModifyContainerComparison.javabycreatingaGeneratorfor
//BerylliumSphere,andchangemain（）tousethatGenerator
//withGenerated.array（）.
importnet.mindview.util.*;
importstaticnet.mindview.util.Print.*;
classBerylliumSphereGeneratorimplementsGenerator<
publicBerylliumSpherenext（）{
returnnewBerylliumSphere（）;
}
publicclassContainerComparison15{
BerylliumSphere[]spheres=newBerylliumSphere[5];
BerylliumSphereGeneratorbsg=newBerylliumSphereGenerator（）;
Generated.array（spheres,bsg）;
print（Arrays.toString（spheres））;
print（spheres[4]）;
sphereList=
5;
i++）
sphereList.add（bsg.next（））;
print（sphereList）;
print（sphereList.get（4））;
//arrays/Ex1.java
//TIJ4ChapterArrays,Exercise1,page752
/*CreateamethodthattakesanarrayofBerylliumSphereasanargument.
*Callthemethod,creatingtheargumentdynamically.Demonstratethat
*ordinaryaggregatearrayintitializationdoesn'
tworkinthiscase.
*Discovertheonlysituationswhereordinaryaggregatearrayinitialization
*works,andwheredynamicaggregatearrayinitializationisredundant.
classA{publicStringtoString（）{return"
AObject"
;
}}
publicclassEx1{
//MethodthattakesBerylliumSphere[]asargument
//andprintstheargumentasarrayelementsandasListorString:
publicstaticvoidtest（BerylliumSphere[]a）{
print（Arrays.asList（a））;
//Genericversion:
publicstatic<
T>
voidtest（T[]t）{
print（Arrays.asList（t））;
//intversion:
publicstaticvoidte
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