Java to access the C ++ method JavaCPP
JavaCPP provides efficient access to local C ++ in Java. JNI technology is used to implement all Java implementations, including Android, Avian, and RoboVM.
JavaCPP provides a series of Annotation functions to map Java code to C ++ code, use an executable jar package to convert the C ++ code to a dynamic link library file that can be called from the JVM.
Maven:
- <dependency>
- <groupId>org.bytedeco</groupId>
- <artifactId>javacpp</artifactId>
- <version>0.11</version>
- </dependency>
Usage:
C ++:
- #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;
- };
- }
Java:
- 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());
- }
- }