A simple example of the interface of a dynamically connected library DLL file that is invoked in Java by calling C + + written __c++

1, first in Java to write a simple class

public class Hello
{public
	native void SayHello ();
	static {
		system.loadlibrary ("Hellodll");
	}
	public static void Main (string[] args) {
    	new Hello (). SayHello ();
    }
}

Compiling the class using Javac Hello.java

Then use Javah hello to generate the Hello.h header file

2. Create a new dynamic link library project in Visual C + + 6.0, project named Hellodll

3. In the project, a new header file named: hello.h, copy the code in the Hello.h file just generated, as follows:

/* Do isn't EDIT this file-it is machine generated/*
#include <jni.h>/
* Header for class Hello/*/

#i Fndef _included_hello
#define _included_hello
#ifdef __cplusplus
extern "C" {
#endif/
*
 * Class:     Hello
 * Method:    SayHello
 * Signature: () V
 /
jniexport void Jnicall Java_hello_sayhello
  (jnienv *, jobject);

#ifdef __cplusplus
}
#endif
#endif

No need to make any changes

At this point, create a new Test.cpp file to implement the function of the header file just now, the code is as follows

#include "Hello.h"
#include <jni.h>

jniexport void Jnicall Java_hello_sayhello
(jnienv *, Jobject) {
	printf ("Hello world,i ' m coming!");
	return;
}

At this point if the compilation will be an error, said that the jni.h file can not be found, as follows:

Fatal error C1083:cannot open include file: ' jni.h ': No such file or directory

Only step 4 can be done at this point

4. Copy the Jni_md.h files under Jni.h and ~\jdk1.6.0_25\include\win32 to Visual C + + 6.0 in the JDK installation directory ~\jdk1.6.0_25\include D:\Microsoft In the Visual studio\vc98\include directory

5, at this time in the compilation of linked Test.cpp files, you can generate dynamic link library files:

Then copy the file to the same directory as the Hello.class file, run the Java file, you can invoke the interface of C/E + + writing implementation, that is, dynamic link library file

The results of the operation are as follows:

This calls success.