如何创建和使用Runnable Jar FileWord下载.docx

如何创建和使用Runnable Jar FileWord下载.docx

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publicclassHello{

publicstaticvoidmain（String[]args）{

System.out.println（"

HelloWorld!

"

）;

}

}

Right-clickon“src”,select“Export”,thenselectJava/JARfie

Backtotop

Specifythepathofthenewcreatedjarfile:

NextNext

Finish

Seewhatwehaveinfoldertest:

Seethecontentof“MANIFEST.MF”

Backtotop

Step1:

Createatextfile,renameitto“Hello.java”,whichsimplyprints“HelloWorld!

Step2:

Compileitusingjavac.exe,andwegetHello.class,

Delete“Hello.java”,becausewedon'

tneeditanymore:

Step3:

Move“Hello.class”tofolder“test”

Step4:

Createanewfoldercalled“META-INF”infolder“test”

Step5:

Createanewtextfilecalled“MANIFEST.MF”infolder“META-INF”

Step6:

Editfile“MANIFEST.MF”,addanewline:

Main-Class:

Hello

alinebreakisnecessaryattheendofaboveline.

Abovepictureshowsthecorrectinput,

Followingpictureshowsthewronginput:

Difference:

positionofthecursor.

Inanotherword,afterinput“Main-Class:

Hello”inthefile,weneedhit“Enter”keytoinputanewline,whichisnecessary!

Step7:

Run“jarcvfma.jarMETA-INF/MANIFEST.MF.”indirectoryof“test”togetjarfile.

thedotisnecessary,itmeanscurrentdirectory.

Byabovecommand,wegetfollowingexecutablejarfile:

a.jar

Step8:

Runthejarpackageby“java–jar<

jar-file-name>

”

Question:

Whatwillhappenifwedon'

tinputanewlineinstep6?

Answer:

Wewillgetfollowingerror:

2,Forprojectwithreferencedjarfiles:

Thisprojectiscalledtest,thecodeislikebelow:

packagecom.t;

importcom.person.Person;

publicclassHello{

publicstaticvoidmain（String[]args）{

Personperson=newPerson（）;

person.setName（args[0]）;

person.setGender（args[1]）;

person.setAge（Integer.parseInt（args[2]））;

Hello!

\nname:

"

+person.getName（）+"

\ngender:

+person.getGender（）+"

\nage:

+person.getAge（））;

Backtotop

Itrequiredanotherlibrarycalledperson.jar

Codeinproject“person”:

packagecom.person;

publicclassPerson{

privateStringname=null;

privateStringgender=null;

privateintage=0;

publicStringgetName（）{

returnname;

publicvoidsetName（Stringname）{

this.name=name;

publicStringgetGender（）{

returngender;

publicvoidsetGender（Stringgender）{

this.gender=gender;

publicintgetAge（）{

returnage;

publicvoidsetAge（intage）{

this.age=age;

Weneedmakearunnablejarpackage:

Myeclipseversion:

EclipseJavaEEIDEforWebDevelopers.

Version:

HeliosServiceRelease2

Buildid:

20110218-0911

（c）CopyrightEclipsecontributorsandothers2005,2011.Allrightsreserved.

Visithttp:

//www.eclipse.org/webtools

Step1

Right-clickon“src”Export

Step2

Select“RunnableJARFile”Next

Step3

Specifyexportdestination:

Select“OK”

ThenwegettheJARfileinthespecifiedpath:

Step4

Run“java-jartest.jartimmale31”indirectory“C:

\Tim”

Result:

succeed

Step5

Extracttest.jartofoldertest,andcheckwhatareinit

Contentof“MANIFEST.MF”:

Manifest-Version:

1.0

Class-Path:

.

com.t.Hello

Step1:

thesameasMethod1

alsosucceed

Contentof“MANIFEST.MF”

Rsrc-Class-Path:

./person.jar

Rsrc-Main-Class:

org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader

Step2:

Asyoucansee,inadditionto“test.jar”,anewfolderiscreated:

“test_lib”

Result:

alsosucceed

.test_lib/person.jar

Method4（thismethodhelpsyouunderstandthestructureofjarfile）

Select“JARFile”insteadof“RunnableJARFile”

Butwhenwerunit,we`llgetanerror:

“NoClassDefFoundError”

Why?

Afteryouseestep5,youwillunderstand

Checkthecontentoftest.jar,extractittofolder“test”first

Asyoucansee,

Thereisnoperson.jarinthetest.jar

ThereisalsonoClass-Pathdefinitionin“MANIFEST.MF”.

Thisiswhythemainclasscannotfindclass“Person”

Whatisthesolution?

SeeStep6please:

Step6

Exportproject“person”toaJARfile:

Sonow,wehavetwojarfiles,seeabovepicture.

Createanewfoldercalled“all”,movethetwojarfileintofolder“all”

Right-clickon“test.jar”,extracthere

Note:

compressiontoolsuchas“winrar”isneeded.

Delete“test.jar”

Backupfile“C:

\Tim\all\META-INF\MANIFEST.MF”tootherplace.

Thecontentofwhichis:

Right-clickon“person.jar”,extracthere

Whenyouareaskedifreplaceexistingfiles,select“YestoAll”

Delete“person.jar”

Checkcontentof“C:

\Tim\all\META-INF\MANIFEST.MF”again:

Herewecansee,thekeypart（definitionofMain-Class）isnotinMANIFEST.MFanymore.

Replacefile“C:

\Tim\all\META-INF\MANIFEST.MF”withthebackedupone.

Therefore,wehaveMain-ClassdefinitioninfileMANIFEST.MFagain:

Run“jarcvfmnewtest.jarmeta-inf/manifest.mf.”indirectory“all”:

AndnowwehaveanewJARfilecalled“newtest.jar”:

Runthejarfileindirectory“all”:

Succeedagain.

Now,let`sseethefilesstructure:

Conclusion:

bythismethod,wecanmakethisfilestructuremanually.

PutmainclassHello.classandreferencedclassPerson.classanditsparentsfolderinsamemotherfolder

AndkeepcontentofMETA-INF/MANIFEST.MFcorrect,pointingoutthecorrectmainclass.