标签：jni work load ext ret jniexport ifd stat wstring
TestJNI.java
1 public class TestJNI { 2 3 static{ 4 System.load("/home/buyizhiyou/workspace/JNI/src/libTestJNI.so");//注意此处加载.so文件 5 } 6 public native String test(String inp);//此处需要声明 7 8 public static void main(String[] args){ 9 TestJNI j=new TestJNI(); 10 String ret=j.test("inputs"); 11 System.out.println(ret); 12 } 13 }
javah -jni TestJNI 生成TestJNI.h,这个文件不用自己改，如下:
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class TestJNI */
#ifndef _Included_TestJNI
#define _Included_TestJNI
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: TestJNI
* Method: test
* Signature: (Ljava/lang/String;)Ljava/lang/String;
*/
JNIEXPORT jstring JNICALL Java_TestJNI_test
(JNIEnv *, jobject, jstring);
#ifdef __cplusplus
}
#endif
#endif
然后用c++实现JNICALL Java_TestJNI_test方法,注意c++类型和JNI类型的转换:
#include "TestJNI.h" #include<iostream> using namespace std; JNIEXPORT jstring JNICALL Java_TestJNI_test(JNIEnv * env, jobject, jstring inp) { char* s = (char*)env->GetStringUTFChars(inp, NULL); cout<<s<<endl; jstring ret = env->NewStringUTF("return"); return ret; }
编译c++成.so文件，注意指定头文件路径，因为需要用到jni.h, jni_md.h:
g++ TestJNI.cpp -I/usr/lib/jvm/java-8-oracle/include/linux/ -I/usr/lib/jvm/java-8-oracle/include/ -fPIC -shared -o libTestJNI.so
然后javac TestJNI.java编译,java TestJNI执行即可。
标签：jni work load ext ret jniexport ifd stat wstring
原文地址：https://www.cnblogs.com/buyizhiyou/p/10858677.html
