我使用JNA 4.0.0访问从Java某些DLL函数,这个DLL的固有函数声明为以下几点:JNA异常“主要” java.lang.Error的:无效的内存访问(来源不明)
int ApplicationInit(HANDLE hEMV, TLV *tlv_Appl, TLV *tlv_AIP);
输入参数下
/* Opaque structure */
typedef void *HANDLE;
typedef struct
{
unsigned char *_lenptr; /* pointer to 'len' field (Private member) */
unsigned int _len; /* 'outer' length, specified by user (Private member) */
unsigned short _offset;
unsigned short len; /* number of bytes (Public member) */
unsigned long tag; /* Tag tag (Public member) */
unsigned char *val; /* byte string (Public member) */
unsigned char _tagptr[256]; /* Container for TLV data (Private member) */
} TLV;
等类型描述,我声明它库接口,如下内:
public static class HANDLE extends PointerType {
public HANDLE(Pointer address) {
super(address);
}
public EMV_HANDLE() {
super();
}
}
public class TLV extends Structure {
/**
* pointer to 'len' field (Private member)<br>
* C type : unsigned char*
*/
public Pointer _lenptr;
/** 'outer' length, specified by user (Private member) */
public int _len;
public short _offset;
/** number of bytes (Public member) */
public short len;
/** Tag tag (Public member) */
public NativeLong tag;
/**
* byte string (Public member)<br>
* C type : unsigned char*
*/
public Pointer val;
/**
* Container for TLV data (Private member)<br>
* C type : unsigned char[256]
*/
public byte[] _tagptr = new byte[256];
public TLV() {
super();
}
protected List<? > getFieldOrder() {
return Arrays.asList("_lenptr", "_len", "_offset", "len", "tag", "val", "_tagptr");
}
/**
* @param _lenptr pointer to 'len' field (Private member)<br>
* C type : unsigned char*<br>
* @param _len 'outer' length, specified by user (Private member)<br>
* @param len number of bytes (Public member)<br>
* @param tag Tag tag (Public member)<br>
* @param val byte string (Public member)<br>
* C type : unsigned char*<br>
* @param _tagptr Container for TLV data (Private member)<br>
* C type : unsigned char[256]
*/
public TLV(Pointer _lenptr, int _len, short _offset, short len, NativeLong tag, Pointer val, byte _tagptr[]) {
super();
this._lenptr = _lenptr;
this._len = _len;
this._offset = _offset;
this.len = len;
this.tag = tag;
this.val = val;
if ((_tagptr.length != this._tagptr.length))
throw new IllegalArgumentException("Wrong array size !");
this._tagptr = _tagptr;
}
public static class ByReference extends TLV implements Structure.ByReference {
};
public static class ByValue extends TLV implements Structure.ByValue {
};
}
int EMV_ApplicationInit(AppdefLibrary_EMVCT.EMV_HANDLE hEMV, TLV.ByReference tlv_Appl, TLV.ByReference tlv_AIP);
,然后我把它通过以下方式:
EMV_HANDLE hEMV= new EMV_HANDLE();
TLV.ByReference tlv_Appl=new TLV.ByReference();
TLV.ByReference tlv_AIP=new TLV.ByReference();
System.out.println(AppdefLibrary.INSTANCE.ApplicationInit(hEMV, tlv_Appl, tlv_AIP));
,但我发现以下异常:
Exception in thread "main" java.lang.Error: Invalid memory access
at com.sun.jna.Native.invokeInt(Native Method)
at com.sun.jna.Function.invoke(Function.java:383)
at com.sun.jna.Function.invoke(Function.java:315)
at com.sun.jna.Library$Handler.invoke(Library.java:212)
at com.sun.proxy.$Proxy1.ApplicationInit(Unknown Source)
at test.Test.main(Test.java:192)
请帮忙,谢谢您的关注!当你试图访问您没有正确分配的本地端内存
你好@Daniel Widdis, 谢谢你的关注。 我按照你的指示。首先我切换到jna-4.2.2.jar和jna-platform-4.2.2.jar。其次,我尝试通过直接使用WinNT.HANDLE类来引用TLV结构,如下所示: 'WinNT.HANDLE myHandle = new WinNT.HANDLE(); TLV tlv_Appl = new TLV(); TLV tlv_AIP = new TLV(); 的System.out.println(AppdefLibrary.INSTANCE.ApplicationInit(myHandle,tlv_Appl,tlv_AIP));'' 但我得到相同的异常 – Bace
@Bace你的方法签名都正确,但如果你仍然获取错误意味着API正在期待你没有给出的值。这通常由API指定。 ApplicationInit()API文档是否指定你初始化结构的任何成员?常见的问题可能是HANDLE预期会使用其他方法初始化,或者您应该预先填充TLV结构的成员。 –
你好@Daniel Widdis,再次感谢你。在我看来,HANDLE预计会使用其他方法初始化。我现在正在测试,在任何情况下我都会回复你。 – Bace