JNI：在路径上找到库，但方法不是（java.lang.UnsatisfiedLinkError） [英] JNI: Library is Found on Path, but Method is not (java.lang.UnsatisfiedLinkError)

问题描述

我试图使用JNI并获取java.lang.UnsatisfiedLinkError。不像其他百万个问题，关于这个问题，我有我的路径上的lib，甚至看到异常更改时，我删除它。

这是我的java类代码：

  package com; 
 
 public class Tune {
 static {
 System.loadLibrary（lala）; 
} 
 public static void main（String [] args）{
 Tune j = new Tune（）; 
 System.out.println（2 + 6 =+ j.add（2，6））; 
} 
 native public int add（int x，int y）; 
} 
  

这是我javah产生的头文件的节略部分：

  / * 
 *类：com_Tune 
 *方法：add 
 *签名： b $ b * / 
 JNIEXPORT jint JNICALL Java_com_Tune_add 
（JNIEnv *，jobject，jint，jint）; 
  

这是我的c ++代码：

  #include< jni.h> 
 #include< com_Tune.h> 
 
 JNIEXPORT jint JNICALL Java_com_Tune_add 
（JNIEnv * env，jobject obj，jint x，jint y）{
 return x + y; 
} 
  

这是我从eclipse获取的运行时异常：

 线程main中的异常java.lang.UnsatisfiedLinkError：com.Tune.add（II）I 
 at com.Tune.add Native方法）
 at com.Tune.main（Tune.java:9）
  

读取上面的异常意味着它DID找到库lala，但是方法add仍然没有定义。我看到的项目和教程之间唯一不同的是：

• Mine使用一个包，而不是默认包
  
  
  
  • Mine有一个返回值。
  
  
  • 我移动了我的dll它已创建（我不认为这会中断，因为我的路径配置。）
  
  

如何实现？

其他信息：

操作系统：Windows 7

JDK：1.6.0_31（对于x86,32位的jvm）

C ++ IDE：Code :: Blocks（DLL由Code :: Blocks IDE自动编译） >
C ++编译器：MinGW32-g ++（GNU C ++编译器）

我有C：\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ _\include

我在C：\_\lib中有lala.dll

环境变量：

PATH：C：\Program Files（x86）\NVIDIA Corporation \PhysX\Common;％CommonProgramFiles％\Microsoft Shared\Windows Live; C：\Program Files（x86）\AMD APP\\ \\ bin \x86_64; C：\Program Files（x86）\AMD APP\bin \x86;％SystemRoot％\system32;％SystemRoot％;％SystemRoot％\System32\Wbem;％SYSTEMROOT％ \System32\WindowsPowerShell\v1.0\; C：\Program Files（x86）\ATI Technologies\ATI.ACE\Core-Static; C：\Apps;％JAVA_HOME％\bin ; C：\Program Files\MySQL\MySQL Server 5.5 \bin;％MAVEN_HOME％\bin;％HADOOP_INSTALL％\bin; c：\Program Files（x86）\ Microsoft SQL Server \100 \Tools\Binn \; c：\Program Files \ Microsoft SQL Server \100\Tools\Binn\; c：\Program Files \ Microsoft SQL Server \100\DTS\\ \\ Binn \; C：\MinGW\bin; C：\Program Files（x86）\GnuWin32\bin; C：_\path; C：\_\lib; C：\程序文件（x86）\Microsoft Visual Studio 10.0 \VC\bin; C：\_\include

解决方案

只是猜测...你的dll依赖于另一个dll，不是在路径上？ MinGW模块通常依赖于特定的C运行时库。

I'm trying to use JNI and getting java.lang.UnsatisfiedLinkError. Unlike the other million questions asked about this, I have the lib on my path, and have even seen the exception change when I remove it. I'm sure that something is wrong with the dll I have created, but I'm not sure what.

Here is my java class code:

package com;

public class Tune {
    static {
        System.loadLibrary("lala");
    }
    public static void main(String[] args) {
        Tune j = new Tune();
        System.out.println("2+6="+j.add(2, 6));
    }
    native public int add(int x,int y);
}

Here is the abridged portion of my javah produced header file:

/*
 * Class:     com_Tune
 * Method:    add
 * Signature: (II)I
 */
JNIEXPORT jint JNICALL Java_com_Tune_add
  (JNIEnv *, jobject, jint, jint);

Here is my c++ code:

#include <jni.h>
#include <com_Tune.h>

JNIEXPORT jint JNICALL Java_com_Tune_add
  (JNIEnv * env, jobject obj, jint x, jint y) {
    return x+y;
  }

Here is the runtime exception I get from eclipse:

Exception in thread "main" java.lang.UnsatisfiedLinkError: com.Tune.add(II)I
    at com.Tune.add(Native Method)
    at com.Tune.main(Tune.java:9)

I read that the above exception means it DID find the library "lala", but that the method "add" is still not defined. The only things I see different between my project and the tutorial are:

• Mine uses a package, instead of the default package (shouldn't tutorials really do this?!?! come on let's get professional)
  • Mine has a return value.
  • I moved my dll after it was created (I don't think this will break it since my path is configured.)

How is this possible?

Other Info:

OS: Windows 7
JDK: 1.6.0_31 (for x86, 32 bit jvm)
C++ IDE: Code::Blocks (the dll was compiled automatically by the Code::Blocks IDE)
C++ compiler: MinGW32-g++ (the GNU C++ compiler)

I have jni.h and com_Tune.h in C:\_\include
I have lala.dll in C:\_\lib

Environment Variables:
PATH: C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;%CommonProgramFiles%\Microsoft Shared\Windows Live;C:\Program Files (x86)\AMD APP\bin\x86_64;C:\Program Files (x86)\AMD APP\bin\x86;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static;C:\Apps;%JAVA_HOME%\bin;C:\Program Files\MySQL\MySQL Server 5.5\bin;%MAVEN_HOME%\bin;%HADOOP_INSTALL%\bin;c:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\MinGW\bin;C:\Program Files (x86)\GnuWin32\bin;C:_\path;C:\_\lib;C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin;C:\_\include

解决方案

Just guessing... Is your dll depends on another dll that is not on the path? MinGW modules usually depend on specific C runtime library.

这篇关于JNI：在路径上找到库，但方法不是（java.lang.UnsatisfiedLinkError）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！