JavaCPP 技术使用经验总结

#include <string>  namespace LegacyLibrary {  class LegacyClass {  public:  const std::string& get_property() { return property; }  void set_property(const std::string& property) { this->property = property; }  std::string property;  }; }

import org.bytedeco.javacpp.*; import org.bytedeco.javacpp.annotation.*;  @Platform(include="LegacyLibrary.h") @Namespace("LegacyLibrary") public class LegacyLibrary {  public static class LegacyClass extends Pointer {  static { Loader.load(); }  public LegacyClass() { allocate(); }  private native void allocate();   // to call the getter and setter functions   public native @StdString String get_property(); public native void set_property(String property);   // to access the member variable directly  public native @StdString String property(); public native void property(String property);  }   public static void main(String[] args) {  // Pointer objects allocated in Java get deallocated once they become unreachable,  // but C++ destructors can still be called in a timely fashion with Pointer.deallocate()  LegacyClass l = new LegacyClass();  l.set_property("Hello World!");  System.out.println(l.property());  } }

$ javac -cp javacpp.jar LegacyLibrary.java  $ java -jar javacpp.jar LegacyLibrary $ java -cp javacpp.jar LegacyLibrary Hello World!

/home/zhoumingyao/javacpp-1.0-bin/javacpp-bin [root@node1:2 javacpp-bin]# ls -lrt 总用量 348 -rw-r--r-- 1 root root 30984 7 月 11 00:59 LICENSE.txt -rw-r--r-- 1 root root 21986 7 月 11 08:52 README.md -rw-r--r-- 1 root root 31955 7 月 11 08:53 CHANGELOG.md -rw-r--r-- 1 root root 243318 7 月 11 12:20 javacpp.jar -rw-r--r-- 1 root root 285 8 月 11 16:07 LegacyLibrary.h -rw-r--r-- 1 root root 1026 8 月 11 16:13 LegacyLibrary.java -rw-r--r-- 1 root root 643 8 月 11 16:13 LegacyLibrary$LegacyClass.class -rw-r--r-- 1 root root 794 8 月 11 16:13 LegacyLibrary.class drwxr-xr-x 2 root root 4096 8 月 11 16:13 linux-x86_64 [root@node1:2 javacpp-bin]# ls -lrt linux-x86_64 总用量 36 -rwxr-xr-x 1 root root 35784 8 月 11 16:13 libjniLegacyLibrary.so

1。下载 Maven 并上传到服务器，这里上传到了/root 目录下面； 2。vi /etc/profile 在最后两行加上代码： export MAVEN_HOME=/root/apache-maven-3.1.1 export PATH=${MAVEN_HOME}/bin:${PATH} 3。source /etc/profile 4。[root@node1:2 bin]# mvn -v Apache Maven 3.1.1 (0728685237757ffbf44136acec0402957f723d9a; 2013-09-17 23:22:22+0800) Maven home: /root/apache-maven-3.1.1 Java version: 1.8.0_45, vendor: Oracle Corporation Java home: /usr/share/jdk1.8.0_45/jre Default locale: zh_CN, platform encoding: UTF-8 OS name: "linux", version: "2.6.32-504.el6.x86_64", arch: "amd64", family: "unix"

<dependency>  <groupId>org.bytedeco.javacpp-presets</groupId>  <artifactId>${moduleName}</artifactId>  <version>${moduleVersion}-1.0</version>  </dependency>

[root@localhost javacpp-presets]# mvn install --projects ffmpeg [INFO] Scanning for projects... Downloading: http://repo.maven.apache.org/maven2/org/sonatype/plugins/                 nexus-staging-maven-plugin/1.6/nexus-staging-maven-plugin-1.6.pom Downloaded: http://repo.maven.apache.org/maven2/org/sonatype/plugins/                 nexus-staging-maven-plugin/1.6/nexus-staging-maven-plugin-1.6.pom (12 KB at 0.7 KB/sec) Downloading: http://repo.maven.apache.org/maven2/org/sonatype/                 nexus/maven/nexus-staging/1.6/nexus-staging-1.6.pom Downloaded: http://repo.maven.apache.org/maven2/org/sonatype/                 nexus/maven/nexus-staging/1.6/nexus-staging-1.6.pom (3 KB at 3.8 KB/sec) Downloading: http://repo.maven.apache.org/maven2/org/sonatype/                 nexus/maven/nexus-maven-plugins/1.6/nexus-maven-plugins-1.6.pom Downloaded: http://repo.maven.apache.org/maven2/org/sonatype/                 nexus/maven/nexus-maven-plugins/1.6/nexus-maven-plugins-1.6.pom (17 KB at 7.8 KB/sec) Downloading: http://repo.maven.apache.org/maven2/org/sonatype/                 buildsupport/public-parent/5/public-parent-5.pom

./cppbuild.sh -platform linux-x86_64 install ffmpeg

while [[ $# > 0 ]]; do  case "$1" in  -platform)  shift  PLATFORM="$1"  ;;  install)  OPERATION=install  ;;  clean)  OPERATION=clean  ;;  *)  PROJECTS+=("$1")  ;;  esac  shift done

case $OPERATION in  install)  if [[ ! -d $PROJECT ]]; then  echo "Warning: Project /"$PROJECT/" not found"  else  echo "Installing /"$PROJECT/""  mkdir -p $PROJECT/cppbuild  pushd $PROJECT/cppbuild  source ../cppbuild.sh  popd  fi

// // This tutorial was written by Stephen Dranger (dranger@gmail.com). // // Code based on a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de) // Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1  // A small sample program that shows how to use libavformat and libavcodec to // read video from a file. // // Use the Makefile to build all examples. // // Run using // // tutorial01 myvideofile.mpg // // to write the first five frames from "myvideofile.mpg" to disk in PPM // format.  #include <libavcodec/avcodec.h> #include <libavformat/avformat.h> #include <libswscale/swscale.h>  #include <stdio.h>  void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame) { FILE *pFile; char szFilename[32]; int y;  // Open file sprintf(szFilename, "frame%d.ppm", iFrame); pFile=fopen(szFilename, "wb"); if(pFile==NULL) return;  // Write header fprintf(pFile, "P6/n%d %d/n255/n", width, height);  // Write pixel data for(y=0; y<height; y++) fwrite(pFrame->data[0]+y*pFrame->linesize[0], 1, width*3, pFile);  // Close file fclose(pFile); }  int main(int argc, char *argv[]) { AVFormatContext *pFormatCtx = NULL; int i, videoStream; AVCodecContext *pCodecCtx = NULL; AVCodec *pCodec = NULL; AVFrame *pFrame = NULL;  AVFrame *pFrameRGB = NULL; AVPacket packet; int frameFinished; int numBytes; uint8_t *buffer = NULL;  AVDictionary *optionsDict = NULL; struct SwsContext *sws_ctx = NULL;

<project>  <modelVersion>4.0.0</modelVersion>  <groupId>org.bytedeco.javacpp-presets.ffmpeg</groupId>  <artifactId>tutorial01</artifactId>  <version>1.0</version>  <dependencies>  <dependency>  <groupId>org.bytedeco.javacpp-presets</groupId>  <artifactId>ffmpeg</artifactId>  <version>2.7.1-1.0</version>  </dependency>  </dependencies> </project>

import java.io.*; import org.bytedeco.javacpp.*; import static org.bytedeco.javacpp.avcodec.*; import static org.bytedeco.javacpp.avformat.*; import static org.bytedeco.javacpp.avutil.*; import static org.bytedeco.javacpp.swscale.*;  public class testJavaCPP {  static void SaveFrame(AVFrame pFrame, int width, int height, int iFrame)  throws IOException {  // Open file  OutputStream stream = new FileOutputStream("frame" + iFrame + ".ppm");   // Write header  stream.write(("P6/n" + width + " " + height + "/n255/n").getBytes());   // Write pixel data  BytePointer data = pFrame.data(0);  byte[] bytes = new byte[width * 3];  int l = pFrame.linesize(0);  for(int y = 0; y < height; y++) {  data.position(y * l).get(bytes);  stream.write(bytes);  }   // Close file  stream.close();  }   public static void main(String[] args) throws IOException {  AVFormatContext pFormatCtx = new AVFormatContext(null);  int i, videoStream;  AVCodecContext pCodecCtx = null;  AVCodec pCodec = null;  AVFrame pFrame = null;  AVFrame pFrameRGB = null;  AVPacket packet = new AVPacket();  int[] frameFinished = new int[1];  int numBytes;  BytePointer buffer = null;   AVDictionary optionsDict = null;  SwsContext sws_ctx = null;   if (args.length < 1) {  System.out.println("Please provide a movie file");  System.exit(-1);  }  // Register all formats and codecs  av_register_all();   // Open video file  if (avformat_open_input(pFormatCtx, args[0], null, null) != 0) {  System.exit(-1); // Couldn't open file  }   // Retrieve stream information  if (avformat_find_stream_info(pFormatCtx, (PointerPointer)null) < 0) {  System.exit(-1); // Couldn't find stream information  }   // Dump information about file onto standard error  av_dump_format(pFormatCtx, 0, args[0], 0);   // Find the first video stream  videoStream = -1;  for (i = 0; i < pFormatCtx.nb_streams(); i++) {  if (pFormatCtx.streams(i).codec().codec_type() == AVMEDIA_TYPE_VIDEO) {  videoStream = i;  break;  }  }  if (videoStream == -1) {  System.exit(-1); // Didn't find a video stream  }   // Get a pointer to the codec context for the video stream  pCodecCtx = pFormatCtx.streams(videoStream).codec();   // Find the decoder for the video stream  pCodec = avcodec_find_decoder(pCodecCtx.codec_id());  if (pCodec == null) {  System.err.println("Unsupported codec!");  System.exit(-1); // Codec not found  }  // Open codec  if (avcodec_open2(pCodecCtx, pCodec, optionsDict) < 0) {  System.exit(-1); // Could not open codec  }   // Allocate video frame  pFrame = av_frame_alloc();   // Allocate an AVFrame structure  pFrameRGB = av_frame_alloc();  if(pFrameRGB == null) {  System.exit(-1);  }   // Determine required buffer size and allocate buffer  numBytes = avpicture_get_size(AV_PIX_FMT_RGB24,  pCodecCtx.width(), pCodecCtx.height());  buffer = new BytePointer(av_malloc(numBytes));   sws_ctx = sws_getContext(pCodecCtx.width(), pCodecCtx.height(),  pCodecCtx.pix_fmt(), pCodecCtx.width(), pCodecCtx.height(),  AV_PIX_FMT_RGB24, SWS_BILINEAR, null, null, (DoublePointer)null);   // Assign appropriate parts of buffer to image planes in pFrameRGB  // Note that pFrameRGB is an AVFrame, but AVFrame is a superset  // of AVPicture  avpicture_fill(new AVPicture(pFrameRGB), buffer, AV_PIX_FMT_RGB24,  pCodecCtx.width(), pCodecCtx.height());   // Read frames and save first five frames to disk  i = 0;  while (av_read_frame(pFormatCtx, packet) >= 0) {  // Is this a packet from the video stream?  if (packet.stream_index() == videoStream) {  // Decode video frame  avcodec_decode_video2(pCodecCtx, pFrame, frameFinished, packet);   // Did we get a video frame?  if (frameFinished[0] != 0) {  // Convert the image from its native format to RGB  sws_scale(sws_ctx, pFrame.data(), pFrame.linesize(), 0,  pCodecCtx.height(), pFrameRGB.data(), pFrameRGB.linesize());   // Save the frame to disk  if (++i<=5) {  SaveFrame(pFrameRGB, pCodecCtx.width(), pCodecCtx.height(), i);  }  }  }   // Free the packet that was allocated by av_read_frame  av_free_packet(packet);  }   // Free the RGB image  av_free(buffer);  av_free(pFrameRGB);   // Free the YUV frame  av_free(pFrame);   // Close the codec  avcodec_close(pCodecCtx);   // Close the video file  avformat_close_input(pFormatCtx);   System.exit(0);  }

mvn package exec:java -Dexec.mainClass=testJavaCPP -Dexec.args="您的视频文件"

#!/bin/bash # This file is meant to be included by the parent cppbuild.sh script if [[ -z "$PLATFORM" ]]; then  pushd ..  bash cppbuild.sh "$@" zlib  popd  exit fi  if [[ $PLATFORM == windows* ]]; then  ZLIB_VERSION=128  download http://zlib.net/zlib$ZLIB_VERSION-dll.zip zlib$ZLIB_VERSION-dll.zip  mkdir -p $PLATFORM  cd $PLATFORM  unzip ../zlib$ZLIB_VERSION-dll.zip -d zlib$ZLIB_VERSION-dll  cd zlib$ZLIB_VERSION-dll else  ZLIB_VERSION=1.2.8  download http://zlib.net/zlib-$ZLIB_VERSION.tar.gz zlib-$ZLIB_VERSION.tar.gz  mkdir -p $PLATFORM  cd $PLATFORM  tar -xzvf ../zlib-$ZLIB_VERSION.tar.gz  cd zlib-$ZLIB_VERSION fi  case $PLATFORM in  linux-x86)  CC="gcc -m32 -fPIC" ./configure --prefix=.. --static  make -j4  make install  ;;  *)  echo "Error: Platform /"$PLATFORM/" is not supported"  ;; esac  cd ../.. pom.xml 如清单 16 所示，最终生成 zlib 的 jar 包。

<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">  <modelVersion>4.0.0</modelVersion>   <parent>  <groupId>org.bytedeco</groupId>  <artifactId>javacpp-presets</artifactId>  <version>0.10</version>  </parent>   <groupId>org.bytedeco.javacpp-presets</groupId>  <artifactId>zlib</artifactId>  <version>1.2.8-${project.parent.version}</version>  <packaging>jar</packaging>  <name>JavaCPP Presets for zlib</name>   <dependencies>  <dependency>  <groupId>org.bytedeco</groupId>  <artifactId>javacpp</artifactId>  </dependency>  </dependencies>   <build>  <plugins>  <plugin>  <artifactId>maven-resources-plugin</artifactId>  </plugin>  <plugin>  <artifactId>maven-compiler-plugin</artifactId>  </plugin>  <plugin>  <groupId>org.bytedeco</groupId>  <artifactId>javacpp</artifactId>  </plugin>  <plugin>  <artifactId>maven-jar-plugin</artifactId>  </plugin>  <plugin>  <artifactId>maven-dependency-plugin</artifactId>  </plugin>  <plugin>  <artifactId>maven-source-plugin</artifactId>  </plugin>  <plugin>  <artifactId>maven-javadoc-plugin</artifactId>  </plugin>  </plugins>  </build>  </project>

package org.bytedeco.javacpp.presets;  import org.bytedeco.javacpp.annotation.*; import org.bytedeco.javacpp.tools.*;  @Properties(target="org.bytedeco.javacpp.zlib", value={                                  @Platform(include="<zlib.h>", link="z@.1"),  @Platform(value="windows", link="zdll", preload="zlib1")}) public class zlib implements InfoMapper {  public void map(InfoMap infoMap) {  infoMap.put(new Info("ZEXTERN", "ZEXPORT", "z_const", "zlib_version").cppTypes().annotations())  .put(new Info("FAR").cppText("#define FAR"))  .put(new Info("OF").cppText("#define OF(args) args"))  .put(new Info("Z_ARG").cppText("#define Z_ARG(args) args"))  .put(new Info("Byte", "Bytef", "charf").cast().valueTypes("byte").pointerTypes("BytePointer"))  .put(new Info("uInt", "uIntf").cast().valueTypes("int").pointerTypes("IntPointer"))  .put(new Info("uLong", "uLongf", "z_crc_t", "z_off_t").cast().valueTypes(                                     "long").pointerTypes("CLongPointer"))  .put(new Info("z_off64_t").cast().valueTypes("long").pointerTypes("LongPointer"))  .put(new Info("voidp", "voidpc", "voidpf").valueTypes("Pointer"))  .put(new Info("gzFile_s").pointerTypes("gzFile"))  .put(new Info("gzFile").valueTypes("gzFile"))  .put(new Info("Z_LARGE64", "!defined(ZLIB_INTERNAL) && defined(Z_WANT64)").define(false))  .put(new Info("inflateGetDictionary", "gzopen_w", "gzvprintf").skip());  } }