java - JNI HellowWorld unsatisfiedlinkError 找不到依赖库

Question

我已经从以下位置尝试了 Hello world JNI:

http://home.pacifier.com/~mmead/jni/cs510ajp/

我做了 Java 类:

public class ACTICamWrapperJNI {
    public native void displayMessage();
  static 
  {
    System.loadLibrary("HelloWorldImp"); 

}

}

并调用它:

     public static void main(String args[]) {

            //</editor-fold>
    System.out.println(System.getProperty("java.library.path"));

   ACTICamWrapperJNI test = new ACTICamWrapperJNI();
   }

cpp 文件如下所示:

#include <stdio.h>
#include "HelloWorld.h"   // this header file was generated by javah
JNIEXPORT void JNICALL Java_HelloWorld_displayMessage(JNIEnv *env, jobject obj) 
{
  printf("Hello World!\n");
}

我已经切换到 JDK x86 并使用 X86 编译:

C:\Development\testJNI>javac HelloWorld.java

C:\Development\testJNI>javac HelloWorld.java

C:\Development\testJNI>javah -jni HelloWorld

我使用了 QT 文件夹中的 MINGW32 gcc(希望没问题)

C:\Development\testJNI>gcc -shared -I "C:\Program Files (x86)\Java\jdk1.7.0_40\include" -I"C:\Program Files (x86)\Java\jdk1.7.0_40\include\win32" HelloWorld.cpp -o HelloWorldImp.dll

请注意，我必须添加共享，否则会出现错误:

 undefined reference to `WinMain@16'

C:\Development\testJNI>"C:\Program Files (x86)\Java\jdk1.7.0_40\bin\java.exe" Main
Exception in thread "main" java.lang.UnsatisfiedLinkError: HelloWorld.displayMessage()V
        at HelloWorld.displayMessage(Native Method)
        at Main.main(Main.java:9)

请注意，我已确保我正在运行 x32 jdk 的 java 并使用 x32 版本进行编译，因为我的系统上也有 x64。

也在 NetBean IDE 上试过并遇到了问题:

Exception in thread "main" java.lang.UnsatisfiedLinkError: C:\Windows\System32\HelloWorldImp.dll: Can't find dependent libraries
    at java.lang.ClassLoader$NativeLibrary.load(Native Method)
    at java.lang.ClassLoader.loadLibrary1(ClassLoader.java:1957)
    at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1882)
    at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1872)
    at java.lang.Runtime.loadLibrary0(Runtime.java:849)
    at java.lang.System.loadLibrary(System.java:1087)
    at au.com.ricor.ACTICamWrapperJNI.<clinit>(ACTICamWrapperJNI.java:15)
    at au.com.ricor.CameraPanel.main(CameraPanel.java:58)

我使用的 gcc 版本是:

C:\Development\testJNI>gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=c:/qt/tools/mingw48_32/bin/../libexec/gcc/i686-w64-mingw32/4
.8.0/lto-wrapper.exe
Target: i686-w64-mingw32
Configured with: ../../../src/gcc-4.8.0/configure --host=i686-w64-mingw32 --buil
d=i686-w64-mingw32 --target=i686-w64-mingw32 --prefix=/mingw32 --with-sysroot=/t
emp/x32-480-posix-dwarf-r2/mingw32 --enable-shared --enable-static --disable-mul
tilib --enable-languages=c,c++,fortran,lto --enable-libstdcxx-time=yes --enable-
threads=posix --enable-libgomp --enable-lto --enable-graphite --enable-checking=
release --enable-fully-dynamic-string --enable-version-specific-runtime-libs --d
isable-sjlj-exceptions --with-dwarf2 --disable-isl-version-check --disable-cloog
-version-check --disable-libstdcxx-pch --disable-libstdcxx-debug --disable-boots
trap --disable-rpath --disable-win32-registry --disable-nls --disable-werror --d
isable-symvers --with-gnu-as --with-gnu-ld --with-arch=i686 --with-tune=generic
--with-host-libstdcxx='-static -lstdc++' --with-libiconv --with-system-zlib --wi
th-gmp=/temp/mingw-prereq/i686-w64-mingw32-static --with-mpfr=/temp/mingw-prereq
/i686-w64-mingw32-static --with-mpc=/temp/mingw-prereq/i686-w64-mingw32-static -
-with-isl=/temp/mingw-prereq/i686-w64-mingw32-static --with-cloog=/temp/mingw-pr
ereq/i686-w64-mingw32-static --enable-cloog-backend=isl --with-pkgversion='rev2,
 Built by MinGW-builds project' --with-bugurl=http://sourceforge.net/projects/mi
ngwbuilds/ CFLAGS='-O2 -pipe -I/temp/x32-480-posix-dwarf-r2/libs/include -I/temp
/mingw-prereq/x32-zlib/include -I/temp/mingw-prereq/i686-w64-mingw32-static/incl
ude' CXXFLAGS='-O2 -pipe -I/temp/x32-480-posix-dwarf-r2/libs/include -I/temp/min
gw-prereq/x32-zlib/include -I/temp/mingw-prereq/i686-w64-mingw32-static/include'
 CPPFLAGS= LDFLAGS='-pipe -L/temp/x32-480-posix-dwarf-r2/libs/lib -L/temp/mingw-
prereq/x32-zlib/lib -L/temp/mingw-prereq/i686-w64-mingw32-static/lib -L/temp/x32
-480-posix-dwarf-r2/mingw32/opt/lib'
Thread model: posix
gcc version 4.8.0 (rev2, Built by MinGW-builds project)

谢谢

威廉

Answer 1

要么将类从 au.com.ricor.ACTICamWrapperJNI 重命名为 HelloWorld，要么将 native 函数(在 C++ 文件中)从 Java_HelloWorld_displayMessage() 到 Java_au_com_ricor_ACTICamWrapperJNI_displayMessage()