1、Use native code through JNI (HelloWorld)
天下发表于 2019-12-06 02:50:00
https://www.rgagnon.com/topics/java-jni.html
Use native code through JNI (HelloWorld)
Use native code through JNITag(s): JNI
With MSVC6, create a new Win32 DLL project (simple) and call it javahowto.
In the same directory create a java source called JavaHowTo.javaclass JavaHowTo {
public native String sayHello();
static {
System.loadLibrary("javahowto");
}
}
public native String sayHello();
static {
System.loadLibrary("javahowto");
}
}
Compile the Java program and use javah utility to generate the JavaHowTo.h header file.
javah -jni JavaHowTo
In MSVC6, add the JavaHowTo.h in your project header files
In the Tools - Options menu, set the include directories to include the Java JNI headers files. They are located in [jdk dir]\include and [jdk dir]\include\win32 directories
In the javahowto.cpp source, add
#include "JavaHowTo.h"
JNIEXPORT jstring JNICALL Java_JavaHowTo_sayHello
(JNIEnv *env, jobject obj) {
return env->NewStringUTF("Hello world");
}
JNIEXPORT jstring JNICALL Java_JavaHowTo_sayHello
(JNIEnv *env, jobject obj) {
return env->NewStringUTF("Hello world");
}
Select the Release configuration and build the project.
Copy the javahowto.dll in the same directory as the java program.
Create this new java program
public class JNIJavaHowTo {
public static void main(String[] args) {
JavaHowTo jht = new JavaHowTo();
System.out.println(jht.sayHello());
}
}
public static void main(String[] args) {
JavaHowTo jht = new JavaHowTo();
System.out.println(jht.sayHello());
}
}
Compile and execute.