Java JNA UCHAR和PUCHAR [英] Java JNA UCHAR and PUCHAR

问题描述

我正在寻找Java字符串到' WlanHostedNetworkSetSecondaryKey '和' WlanHostedNetworkSetProperty '.一个人想要一个带有CHAR []的结构中的一个结构，而第一个想要一个PUCHAR.我尝试使用 String，char []，byte []和Memory ，但是它们将继续产生相同的错误(错误的参数或错误的概要文件).可以通过JNA调试更多方法(可能不是:()吗? 除了不是ANSI，我在任何地方都看不到所使用的characterencoding.任何帮助都将非常有用！

I'm looking to get a Java string to 'WlanHostedNetworkSetSecondaryKey' and 'WlanHostedNetworkSetProperty'. One wants a struct within a struct with a CHAR[] and the first one wants a PUCHAR. I tried using String, char[], byte[] and Memory, but they will keep producing me the same errors (Bad parameters or Bad profile something for the first). Any way maybe to debug more with JNA (probably not :()? I also can't read anywhere the characterencoding which is used, except that it's not ANSI.. Any help would be great!

        * DWORD WINAPI WlanHostedNetworkSetSecondaryKey(
        __in        HANDLE hClientHandle,
        __in        DWORD dwKeyLength,
        __in        PUCHAR pucKeyData,
        __in        BOOL bIsPassPhrase,
        __in        BOOL bPersistent,
        __out_opt   PWLAN_HOSTED_NETWORK_REASON pFailReason,
        __reserved  PVOID pvReserved


     * DWORD WINAPI WlanHostedNetworkSetProperty(
        __in        HANDLE hClientHandle,
        __in        WLAN_HOSTED_NETWORK_OPCODE OpCode,
        __in        DWORD dwDataSize,
        __in        PVOID pvData,
        __out_opt   PWLAN_HOSTED_NETWORK_REASON pFailReason,
        __reserved  PVOID pvReserved
        );

有关此文档的更多信息

http://msdn.microsoft.com /en-us/library/dd439496(v=VS.85).aspx

http://jna.java.net/javadoc/overview-summary. html#pointers

http://en.wikipedia.org/wiki/Java_Native_Access

以下评论:

   String buffer = "test";
   ByteBuffer buf = ByteBuffer.allocateDirect(buffer.length()); buf.put(buffer.getBytes()); 
   Pointer pucKeyData = Native.getDirectBufferPointer(buf);

   System.out.println(
           CLibrary.INSTANCE.WlanHostedNetworkSetSecondaryKey(handle.getValue(), 5, pucKeyData, 0, 0, reason, reserved));

推荐答案

我要重述到目前为止的评论(加上一些更正):

I am rephrasing what I have commented so far (plus some corrections):

UCHAR定义为C宏u_byte，它是unsigned byte.但是，在Java中，我们没有unsigned byte类型，只有byte类型的带符号字节.不用担心，要获取Java中的unsigned byte，请使用以下技巧:((int)mybyte & 0xFF)

UCHAR is defined as a C macro u_byte which is an unsigned byte. But, in Java, we don't have an unsigned byte type, just a signed byte from the byte type. Don't worry, to get an unsigned byte in Java, we use this trick: ((int)mybyte & 0xFF)

PUCHAR被定义为C宏POINTER(u_byte)，它是C指针，unsigned byte *指向无符号字节数组.原因是有一个动态数组.

PUCHAR is defined as a C macro POINTER(u_byte) which is a C pointer, unsigned byte * that points to an unsigned byte array. The reason is to have a dynamic array.

但是，如果在JNA Structure中使用byte[]或char[]，则JNA会抱怨，Array fields must be initialized表示未初始化 byte[]或char[]字段.在您的情况下，它违背了使用dwKeyLength字段定义动态无符号字节数组pucKeyData的大小的目的.

But, if you use byte[] or char[] in JNA Structure, JNA will complain, Array fields must be initialized for uninitialized byte[] or char[] field. In your case, it defeats the purpose of having dwKeyLength field to define the size of dynamic unsigned byte array pucKeyData.

pucKeyData的正确JNA类型是Pointer.但是，您需要找到一种方法，根据 WlanHostedNetworkSetSecondaryKey 结构中dwKeyLength长度给出的大小，为pucKeyData字段分配一个数组给Pointer字段.

The right JNA type for the pucKeyData is Pointer. But, you need to find a way to assign an array to this Pointer field for pucKeyData field based on the size given by dwKeyLength length in WlanHostedNetworkSetSecondaryKey structure.

要将初始化的无符号字节数组分配给Pointer，我们需要使用直接ByteBuffer.请记住，在使用后直接释放该直接缓冲区，因为它不再由Java GC管理...

To assign an initialized unsigned byte array to a Pointer, we need to use direct ByteBuffer. Remember to release this direct buffer manually after use since it is no longer managed by Java GC...

String buffer = "1234567890";
DWORD dwKeyLength = new DWORD(buffer.length());
ByteBuffer buf = ByteBuffer.allocateDirect(dwKeyLength.intValue()); 
buf.put(buffer.getBytes()); 
Pointer pucKeyData = Native.getDirectBufferPointer(buf);

System.out.println("pucKeyData data:" + pucKeyData.getString(0));

buf = null;
pucKeyData = null;

如果您从JNA异常中获取了错误的参数，则意味着您的JNA方法的一个或多个参数使用了错误的数据类型.

If you get bad parameters from JNA exception, it means one or more parameters of your JNA method are using incorrect data types.

JNA提供了一些WinDef类类型，例如DWORD.但是不包括诸如PUCHAR的一些WinDef类型.但是，要将整数值分配给DWORD类型并取回它，您需要执行以下操作:

JNA provides a few WinDef class types like DWORD. But a few WinDef types like PUCHAR are not included. But, to assign an integer value to a DWORD type and retrieve it back, you need to do like this:

DWORD dwKeyLength = new DWORD(5);
System.out.println("dwKeyLength integer value: " + dwKeyLength.intValue());

注意:这篇文章基于JNA平台版本3.3.0

Note: this post is based on JNA platform version 3.3.0

这篇关于Java JNA UCHAR和PUCHAR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！