我需要在我的Java应用程序中使用DLL。 DLL正在导出一些函数,作者称之为“Direct DLL API”。我正在尝试在java中定义以下函数声明:
int XcCompress( HXCEEDCMP hComp, const BYTE* pcSource, DWORD dwSourceSize, BYTE** ppcCompressed, DWORD* pdwCompressedSize, BOOL bEndOfData );
在我的扩展库的界面中我声明如下:
int XcCompress(WString hComp, Pointer pcSource, int dwSourceSize, Pointer[] ppcCompressed, IntByReference pdwCompressedSize, boolean bEndOfData);
问题是每次我收到错误:
线程“main”中的异常java.lang.Error:无效的内存访问
所以基本上我已经陷入了困境。
HXCEEDCMP hComp
- 假设存储处理程序到函数,并作为初始DLL DLL /破坏DLL函数的WString工作正常,所以我保持这样。
标题引用“creature”是:
typedef HXCEEDCMP ( XCD_WINAPI *LPFNXCCREATEXCEEDCOMPRESSIONW )( const WCHAR* );
const BYTE* pcSource
- 是压缩的源数据,在我的代码中我以这种方式实例化它:
private static Pointer setByteArrayPointer(String dataToCompress) {
Pointer pointer = new Memory(1024);
pointer.write(0, dataToCompress.getBytes(), 0,
dataToCompress.getBytes().length);
return pointer;
}
DWORD dwSourceSize
- 为此我以这种方式保留内存大小:
String testData = "ABCDABCDABCDAAD";
Pointer source = setByteArrayPointer(testData);
(int) ((Memory)source).size()
BYTE** ppcCompressed
- 函数应在工作完成后填充ppcCompressed参考。我假设我犯了一个错误,通过这样做:
Pointer[] compressed = {new Pointer(1024), new Pointer(1024)};
DWORD* pdwCompressedSize
- 由压缩数据的函数大小返回。我用这种方式映射它:
IntByReference intByReference = new IntByReference();
不确定这是不是好主意...
BOOL bEndOfData
- 我需要将其设置为true。
所以最后我的方法调用,返回一个错误,如下所示:
xceedApiDll.XcCompress(handle, source, (int) ((Memory)source).size(), compressed, intByReference, true);
任何帮助将不胜感激。谢谢。
我想我解决了这个问题(感谢评论家伙)。也许对于使用此库的人来说,它会很有用:
最后,主要问题是处理程序声明和ppcCompressed值。
我使用以下解决方案对我来说很好:
java接口里面的方法声明:
int XcCompress(Pointer hComp, byte[] pcSource, int dwSourceSize, PointerByReference ppcCompressed, IntByReference pdwCompressedSize, int bEndOfData);
int XcUncompress(Pointer hComp, byte[] pcSource, int dwSourceSize, PointerByReference ppcUncompressed, IntByReference pdwUncompressedSize, int bEndOfdata);
用法:
private static final XceedFunctions XCEED_DLL_API;
static {
XCEED_DLL_API = Native.load("XceedZipX64", XceedFunctions.class);
}
private static final String TEST_DATA = "abcabcddd";
//Data pointers
private static Pointer compHandle;
private static byte[] baSource = TEST_DATA.getBytes();
private static PointerByReference pbrCompressed = new PointerByReference();
private static PointerByReference pbrUncompressed = new PointerByReference();
private static IntByReference ibrCompressedSize = new IntByReference();
private static IntByReference ibrUncompressedSize = new IntByReference();
public static void main(String[] args) {
try {
boolean isSuccessfulInit = XCEED_DLL_API.XceedZipInitDLL();
if(isSuccessfulInit) {
compHandle = XCEED_DLL_API.XcCreateXceedCompressionW(new WString("YOUR_LICENCE_KEY_HERE"));
int compressionResult = XCEED_DLL_API.XcCompress(compHandle, baSource, baSource.length, pbrCompressed, ibrCompressedSize, 1);
byte[] compressed = getDataFromPbr(pbrCompressed, ibrCompressedSize);
System.out.println("Compression result: " + compressionResult + " Data: " + new String(compressed));
int decompressionResult = XCEED_DLL_API.XcUncompress(compHandle, compressed, compressed.length, pbrUncompressed, ibrUncompressedSize, 1);
byte[] uncompressed = getDataFromPbr(pbrUncompressed, ibrUncompressedSize);
System.out.println("Decompression result: " + decompressionResult + " Data: " + new String(uncompressed));
}
} finally {
System.out.println("Free memory and shutdown");
if(compHandle != null) {
XCEED_DLL_API.XcDestroyXceedCompression(compHandle);
}
XCEED_DLL_API.XceedZipShutdownDLL();
}
}
private static byte[] getDataFromPbr(PointerByReference pbr, IntByReference ibr) {
return pbr.getValue().getByteArray(0, ibr.getValue());
}
示例输出:
压缩结果:0数据:KLJNLJNII yK
减压结果:0数据:abcabcddd
可用内存和关机