Java JNI Linux-linux上java调用c使用javacpp

• 使用开源项目Javacpp
• 项目地址 https://github.com/bytedeco/javacpp

• Centos8
• OracleJDK+环境变量。jdk下载链接 https://www.oracle.com/technetwork/java/javase/downloads/index.html
• gcc编译工具，dnf install man-pages 或者 yum install man-pages，输入 gcc -version 出现版本信息即可

• NativeLibrary.h 中的 C++代码

#include 
#include 
using namespace std;

namespace NativeLibrary {
    class NativeClass {
        public:
            const std::string& get_property() { return property; }
            void set_property(const std::string& property) { this->property = property; cout << "C++ Received :" << property << endl;}
            std::string property;
    };
}

• NativeLibrary.java 中的Java代码

import org.bytedeco.javacpp.*;
import org.bytedeco.javacpp.annotation.*;

@Platform(include="NativeLibrary.h")
@Namespace("NativeLibrary")
public class NativeLibrary {
    public static class NativeClass extends Pointer {
        static { Loader.load(); }
        public NativeClass() { 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) {
        NativeClass l = new NativeClass();
        l.set_property("Hello World!");
        System.out.println("From C++:"+l.property());
    }
}

• 将 javacpp.jar，NativeLibrary.h，NativeLibrary.java 放到同一个目录下
  

• 运行命令 java -jar javacpp.jar NativeLibrary.java -exec，出现如下信息
  
  文件下出现了编译后的.class文件和.so文件
  

• 通过 Java -cp 运行，注意指出依赖的Jar包 java -cp .:javacpp.jar NativeLibrary
  

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