Linux platform Java call so library-jni use example

First, write a Java file that contains the native method

public class Myjni {public    native void display ();    Public native double sum (double x, double y);    public static void Main (string[] args) {           }}

Next, compile this Java file into an. h file

Javah Myjni

After executing this command, a MyJni.h file is produced in the directory

Third, write a. c file that introduces just the header file

#include <jni.h> #include "MyJni.h" #include <stdio.h>jniexport void Jnicall java_myjni_display (jnienv *env , Jobject obj) {    printf ("Hello JNI");    return;} Jniexport jdouble jnicall java_myjni_sum (jnienv *env,jobject obj,jdouble a,jdouble b) {    return a+b;}

D. Compile the. c file into. O, and then convert to. so or. dll files

Gcc-fpic-d_reentrant-i JDK Path/jdk1.8/include-i jdk path/jdk1.8/include/linux-c myjni.c

The above command compiles the C file into an. o file.

gcc-shared Test.o-o libtest.so

The above command compiles the. o file into a. so file.

Test it in the Java method just now.

public class Myjni {    static {        system.load ("absolute path/libtest.so");    }    Use of JNI keyword Native//    this keyword determines that our methods can be used in C files    //Only declare, do not have to implement public    native void display ();    Public native double sum (double x, double y);    public static void Main (string[] args) {        Myjni myjni = new Myjni ();        System.out.print (Myjni.sum (1, 1));        System.out.print ("\ n");        Myjni.display ();    }}

Linux platform Java call so library-jni use example