package org.demo;

public class JniDemo

{

    public static native int bmp2fea(byte[] bmp, byte[] fea, byte[] err);

    public static native int feaMatch(byte[] fea1, byte[] fea2, String flag, int level);

}

javah -classpath . -jni org.demo.JniDemo

#include <stadio.h>

#include <string.h>

#include 'org_demo_JniDemo.h'

extern int feaMatch(char *pRegAscii, char *pVerAscii, int level);

extern int bmp2fea(unsigned char* bmp, char* feature, char* flag, char* errinfo);

JNIEXPORT jint JNICALL JAVA_org_demo_JniDemo_bmp2fea  (JNIEnv *env, jclass arg, jbyteArray bmp, jbyteArray fea, jbyteArray err)

{

    char out[]  = {  };

    char errinfo[] = {  };

    jbyte* pbmp = (*env)->GetByteArrayElements(env, bmp, );

    jsize inSize = (*env)->GetArrayLength(env, bmp);

    //bmp大小平均150k,使用malloc

    //char *tmp = (char*)malloc(inSize + );

    //memset(tmp, , inSize+);
　　char *tmp = (char*)calloc(inSize+1, sizeOf(char));
　　if (tmp == NULL)
　　{
　　　　(*env)->ThrowNew(env,
　　　　　　(*env)->FindClass(env, "java/lang/OutOfMemoryError"), "jni calloc failed");
　　　　return;
　　}

    memcpy(tmp, pbmp, inSize);

    int ret = bmp2fea((unsigned char*)tmp, (char*)out, (char*)errinfo);

    if (ret == )

    {

        (*env)->SetByteArrayRegion(env, fea, , strlen(out), (jbyte*)out);

        if (strlen(errinfo) > )

             (*env)->SetByteArrayRegion(env, err, , strlen(errinfo), (jbyte*)out);

    }

    else

    {

        if (strlen(errinfo) > )

             (*env)->SetByteArrayRegion(env, err, , strlen(errinfo), (jbyte*)out);

    }

    if (tmp != NULL)

    {

        free(tmp);

    }

    (*env)->ReleaseByteArrayElements(env, bmp, pbmp, JNI_ABORT);

    return rt;

}

JNIEXPORT jint JNICALL Java_org_demo_JniDemo_feaMatch (JNIEnv *env, jclass arg, jbyteArray fea1, jbyteArray fea2, jstring flag, jint level)

{

    char tmp1[] = {  };

    char tmp2[] = {  };

    jbyte* pFea1 = (*env)->GetByteArrayElements(env, fea1, );

    jsize inSize1 = (*env)->GetArrayLength(env, fea1);

    memcpy(tmp1, pFea1, inSize1);

    jbyte* pFea2 = (*env)->GetByteArrayElements(env, fea2, );

    jsize inSize2 = (*env)->GetArrayLength(env, fea2);

    memcpy(tmp2, pFea2, inSize2);
    char* pflag = (char*)(*env)->GetStringUTFChars(env, flag, 0);　

    int ret = feaMatch(tmp1, tmp2, pflag, level);

    (*env)->ReleaseByteArrayElements(env, fea1, pFea1, JNI_ABORT);

    (*env)->ReleaseByteArrayElements(env, fea1, pFea2, JNI_ABORT);
    (*env)->ReleaseStringUTFChars(env, flag, pflag);

    return ret;

}

ODIR=.

EDIR=.

LDIR=.

INC_DIR=./

CC=g++

AR=ar -r

LD=ld

RM=rm -rf

cc=gcc

STRIP=strip

MKDIR=mkdir -p

INCLUDES=-I$(INC_DIR)

CCFLAGS=-g $(INCLUDES) -fPIC

LIBS=-lc -ldl -ldemo

SRC_DIR=./

ALL_DIR=-I$(SRC_DIR) -I/usr/java/jdk1..0_80/include/ -I/usr/java/jdk1..0_80/include/linux/

LIBAPI_SO=$(LDIR)/libengine.so

BIZD=$(EDIR)/test

PROGRAM=$(LIBAPI_SO)

####object files####

LIBAPI_OBJ=$(ODIR)/org_demo_JniDemo.o

####object files####

BIZ_OBJ=$(ODIR)/test.o

##############

all:$(PROGRAM)

force:

$(LIBAPI_SO)::$(LIBAPI_OBJ)

    @echo ----Linking...----

    $(LD) -share -o $(LIBAPI_SO) $(LIBAPI_OBJ) -L./ $(LIBS)

    @echo ----make $@ OK----

$(BIZD)::$(BIZ_OBJ)

    @echo ----Linking...----

    $(cc) -o $(BIZD) $(BIZD_OBJ) -L$(LDIR) $(LIBS) $(CCFLAGS)

    @echo ----make $@ OK----

clean::

    @$(RM) $(ODIR)/*.o $(PROGRAM)

cleanobj::

    @$(RM) $(BIZ_OBJ)

cleanbin::

    @$(RM) $(PROGRAM)

.SUFFIXES:.cpp .c .o .so .a

####common#####

$(ODIR)/%.o:$(SRC_DIR)/%.c

    $(cc) $(CCFLAGS) $< $(ALL_DIR) -c -o $@

package org.demo;

import org.demo.JniDemo;

public class Demo

{

    static {

        // 动态库名： libdemo.so

        System.loadLibrary("demo");

        // libengine.so

        System.loadLibrary("engine");

    }

    public static int bmp2fea(byte[] bmp, byte[] fea, byte[] err)

    {

        return JniDemo.bmp2fea(bmp, fea, err);

    }

    public static int feaMatch(byte[] fea1, byte[] fea2,String flag, int level)

    {

         return JniDemo.feaMatch(fea1, fea2, flag, level);

    }

} 

方法一:
#linux用户环境变量配置：
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/demo/lib/

方法二：
#程序启动是配置JVM参数：
java -Djava.library.path=/demo/lib/ -server -cp $CLASSPATH org.demo.Test