JNI UnsatisfiedLinkError ...签名差异?

时间:2013-05-17 17:29:16

标签: java c++ eclipse java-native-interface

在eclipse中,在64位窗口上,我试图让一个JNI示例工作,包括尝试两种处理输入/输出int参数的方法。该程序运行并执行sayHello(),但以modIntPtr()的以下异常终止:

线程“main”中的异常java.lang.UnsatisfiedLinkError:com.aaa.bbb.ccc.HelloJNI.modIntPtr(I [I] V     at com.aaa.bbb.ccc.HelloJNI.modIntPtr(Native Method)     在com.aaa.bbb.ccc.HelloJNI.main(HelloJNI.java:18)

我仔细检查了库,它里面有modIntPtr。所以我认为它一定是签名问题?在.cpp文件中,modIntPtr有一个jint,jintArray,并返回一个void。那是(我[I] V。在.h文件中,签名是(I [I] V。在HelloJNI.java中,我这样称呼它: new HelloJNI()。modIntPtr(100,intptr); intptr是int []类型。那就是(I [I] V也是。

因此,如果.dll包含modIntPtr方法,我确定它是最新的,我确定程序正在链接正确的.dll,这不是签名问题,还有什么呢?

顺便说一句,如果我注释掉对modIntPtr的调用,modIntRef确实有效。

感谢您的帮助!

HelloJNI.java:

package com.aaa.bbb.ccc;

public class HelloJNI {
    static {
       System.loadLibrary("com_aaa_bbb_ccc");
    }
    // A native method that receives nothing and returns void
    private native void sayHello();
    private native void modIntPtr(int delta, int[] intptr);
    private native void modIntRef(int delta, IntRef intref);

    public static void main(String[] args) {
       int[] intptr = new int[1];
       intptr[0]=42;
       IntRef intref = new IntRef(24);

       new HelloJNI().sayHello();  // invoke the native method
       new HelloJNI().modIntPtr(100, intptr);
       new HelloJNI().modIntRef(100, intref);
    }
 }

HelloJNI.cpp

#include <jni.h>
#include <stdio.h>
#include "HelloJNI.h"

void SayHello(void)
{
   printf("Hello World!\n");
   return;
}

void IntRefNative(int delta, int *intptr)
{
   printf("delta  = %d\n",delta);
   printf("intptr = %d\n",*intptr);

   *intptr += delta;

   printf("After mod...\n");
   printf("intptr = %d\n",*intptr);

   return;
}


JNIEXPORT void JNICALL Java_com_aaa_bbb_ccc_HelloJNI_sayHello(JNIEnv *env, jobject thisObj) {
   SayHello();
   return;
} 

JNIEXPORT void JNICALL Java_com_aaa_bbb_ccc_HelloJNI_modIntPtr(JNIEnv *env, jobject thisObj, jint delta, jintArray intptr) {
   jint *body = env->GetIntArrayElements(intptr, 0);
   printf("delta  = %d\n",delta);
   printf("intptr = %d\n",intptr[0]);

   body[0] += delta;
   env->ReleaseIntArrayElements(intptr, body, 0);

   printf("After mod...\n");
   printf("intptr = %d\n",intptr[0]);
   return;
} 

JNIEXPORT void JNICALL Java_com_aaa_bbb_ccc_HelloJNI_modIntRef(JNIEnv *env, jobject thisObj, jint delta, jobject intref) {
    jclass cls = env->GetObjectClass(intref);

    jmethodID methodID = env->GetMethodID(cls, "getValue", "()I");   
    jint value = env->CallIntMethod(intref, methodID);   
    IntRefNative(delta, (int *)(&value));   
    methodID = env->GetMethodID(cls, "setValue", "(I)V");   
    env->CallVoidMethod(intref, methodID, value);   

   return;
}

HelloJNI.h

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_aaa_bbb_ccc_HelloJNI */

#ifndef _Included_com_aaa_bbb_ccc_HelloJNI
#define _Included_com_aaa_bbb_ccc_HelloJNI
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     com_aaa_bbb_ccc_HelloJNI
 * Method:    sayHello
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_com_aaa_bbb_ccc_HelloJNI_sayHello
  (JNIEnv *, jobject);

/*
 * Class:     com_aaa_bbb_ccc_HelloJNI
 * Method:    modIntPtr
 * Signature: (I[I)V
 */
JNIEXPORT void JNICALL Java_com_aaa_bbb_ccc_HelloJNI_modIntPtr
  (JNIEnv *, jobject, jint, jintArray);

/*
 * Class:     com_aaa_bbb_ccc_HelloJNI
 * Method:    modIntRef
 * Signature: (ILcom/aaa/bbb/ccc/IntRef;)V
 */
JNIEXPORT void JNICALL Java_com_aaa_bbb_ccc_HelloJNI_modIntRef
  (JNIEnv *, jobject, jint, jobject);

#ifdef __cplusplus
}
#endif
#endif

我也会把这个文件也包含在试图找到在java中传递输入/输出或可变int参数的想法的人中......我在各处搜索了一个有效的例子。
IntRef.java

package com.aaa.bbb.ccc;

public class IntRef {

    private int value;

    IntRef() {
        value=0;
    }

    IntRef(int v) {
        value = v;
    }

    /**
     * Returns the integer value of this <code>IntRef</code>
     *
     * @return the value of the integer in native int form
     */
    public int getValue() {
        return value;
    }

    /**
     * Sets the value.
     *
     * @param theValue The value to set
     */
    public void setValue(int theValue) {
        this.value = theValue;
    }
}

1 个答案:

答案 0 :(得分:0)

发布的代码运行没有问题。我会尝试做一个干净的DLL构建; JVM必须从某个地方加载陈旧版本。

顺便说一下,Java_com_aaa_bbb_ccc_HelloJNI_modIntPtr似乎有一个错误:

printf("intptr = %d\n",intptr[0]);

可能应该是:

printf("intptr = %d\n",body[0]);