把底层库打包进JAR的方法

把底层库打包进 JAR的方法[1/3] 背景最近用到 JavaCV做直播项目，在从 github上下载了一个叫RtmpRecoder的项目时，发现RtmpRecoder用到了通过JavaCV运用到ffmpeg，于是下载了JavaCV-bin(javacv-1.2-src.zip)，解压后发现里面只有jar包，却没有发现任何底层库----没有底层库怎么调到ffmpeg那？带着这个疑问， 按照《【JavaCV与Android】在Android工程里配置 JavaCV》里介绍的，解压了其中一个 jar文件ffmpeg-android-arm.jar，在目录javacv-bin/ffmpeg-android-arm/lib/armeabi 下果然发现有一堆动态库。第一次见到 JAR包中也可以包含底层库，很惊奇，就想知道是怎么做到的。就 google搜索了下，发现可以运用Jar2Lib和jace技术生成。此外，JavaCPP技术能便捷的实现把底层库打包进 JAR，能部分代替 JNI技术(但是不能代替底层回调Java层)。在此，贴出具体方法，以备查阅。 [2/3][转]JaceandJar2LibJar2LibLatestVersionJar2LibisacommandlinetoolforgeneratingC++wrapperlibrariesaroundJavaJARfiles.ItexposestheentirepublicJavaAPIoftheJARinthecorrespondingC++sharedlibrary,delegatingtoJavaviaJNI.ThewrappingisperformedusingJace.WeuseJar2LibtogeneratetheBF-CPPbindingsforBio-Formats,whichweuseinourWiscScanacquisitionsoftware.Historicalnote:Jar2LibwasoriginallydevelopedtointegrateBio-FormatswiththeInsightToolkit,forusewiththeFARSIGHTproject.However,wenowhaveandedicatedinter-processsolutionforITKintegrationinsteadwhichiseasiertobuildfromsource,sinceithasnocompile-timedependencies.Nonetheless,BF-CPPisstilltherecommendedin-processsolutionforBio-Formatsnativecodeintegration.Downloadjace-r39.jarWerecommendusingJar2Libviathecppwrap-maven-plugin;see"Installationandusage"below.IfyouprefertouseJar2LibdirectlyfromthecommandlineoutsideMaven:DownloadtheJARslinkedabove,aswellasApacheVelocity1.7anditsdependencies.WithallnecessaryJARsinyourcurrentworkingdirectory,youcanrunJar2Libonthecommandlineasfollows:library.jar[library2.jar...][-conflictsconflicts.txt][-headerheader.txt][-extrascmake_extras.txt][-output/path/to/output-project][-corejava_core_classes.txtLanguageJavaSourceCodejar2libInstallationandUsageTheeasiestwaytouseJar2LibisviaourcppwrapMavenplugin,whichtakesadvantageoftheMavenplug-ininfrastructuretoeasilyconvertaJavalibrarytoC++usingJar2Lib,withoutrequiringanyknowledgeofJar2Lib'sworkingsorsyntax.Forexample,itcircumventsanyneedtodownloadtransitivedependencies.更详细信息，请参考网址技术JavaCPP

是一个开源库，它提供了在

Java

中高效访问本地C++的方法。采用

JNI

技术实现，所以支持所有

Java

实现包括 Android 系统，Avian和RoboVM。3.1JavaCPPPresets--PrebuiltJavaBindingstoC/C++LibrariesThesearepartofaprojectthatwecalltheJavaCPPPresets.ManycoexistinthesameGitHubrepository,andalluseJavaCPPtowrappredefinedC/C++librariesfromopen-sourceland.ThebindingsexposealmostalloftherelevantAPIsandmakethemavailableinaportableanduser-friendlyfashiontoanyJavavirtualmachine(includingAndroid),asiftheywerelikeanyothernormalJavalibraries.WehavepresetsforthefollowingC/C++libraries:OpenCV–[sampleusage]–Morethan2500optimizedcomputervisionandmachinelearningalgorithmsFFmpeg–[sampleusage]–Acomplete,cross-platformsolutiontorecord,convertandstreamaudioandvideoFlyCapture–[sampleusage]–Imageacquisitionandcameracontrolsoftwarelibdc1394–[sampleusage]–Ahigh-levelAPIforDCAM/IIDCcamerasOpenKinect–[sampleusage]–OpensourcelibrarytousetheXboxKinectvideoInput–[sampleusage]–AfreeWindowsvideocapturelibraryARToolKitPlus –[sampleusage]–Marker-basedaugmentedrealitytrackinglibraryChilitags–[sampleusage]–Robustfiducialmarkersforaugmentedrealityandroboticsflandmark–[sampleusage]–Open-sourceimplementationoffaciallandmarkdetectorFFTW–[sampleusage]–FastcomputingofthediscreteFouriertransform(DFT)inoneormoredimensionsGSL–[sampleusage]–TheGNUScientificLibrary,anumericallibraryforCandC++programmersLLVM–[sampleusage]–AcollectionofmodularandreusablecompilerandtoolchaintechnologiesLeptonica–[sampleusage]–SoftwareusefulforimageprocessingandimageanalysisapplicationsTesseract–[sampleusage]–ProbablythemostaccurateopensourceOCRengineavailableCaffe–[sampleusage]–AfastopenframeworkfordeeplearningCUDA –[sampleusage]–ArguablythemostpopularparallelcomputingplatformforGPUsMXNet –[sampleusage]–FlexibleandefficientlibraryfordeeplearningTensorFlow–[sampleusage]–ComputationusingdataflowgraphsforscalablemachinelearningAddhereyourfavoriteC/C++library,forexample:OpenNI,OpenMesh,PCL,etc.Readabouthowtodo