C# C++ Java接口类型转换

　　最近这几天做了一个兼职 ，主要是把C语言以及C#语言封装的dll，经过C++中转为Java语言支持的，主要其中的问题就是类型转换，在此列出常用类型的转换过程。

 #include "stdafx.h"
 #include <cstdlib>
 #include <cstdio>
 #include <iostream>
 #include "www_cnblogs_com\cyjwdm0503.h"
 #include <malloc.h>
 #include <Windows.h>

 using namespace std;
 using namespace  System::Runtime::InteropServices;
 using namespace  System;

 //char* ->c#
 System::String^ charptrtoCstring( const char* str )
 {
     System::String^ str1  =  Marshal::PtrToStringAnsi((IntPtr)(char*)str);
     return str1;
 }

 //C#->char*
 char* Cstringtocharptr( System::String^ s )
 {
     char* buffer = (char*)(void*)Marshal::StringToHGlobalAnsi(s);
     return buffer;
 }

 //jstring ->char*
 char* jstringTocharptr( JNIEnv *env, jstring jstr )
 { //UTF8/16转换成gb2312
     int length = (env)->GetStringLength(jstr );
     const jchar* jcstr = (env)->GetStringChars(jstr,  );
     char* rtn = (char*)malloc( length*+ );
     int size = ;
     size = WideCharToMultiByte( CP_ACP, , (LPCWSTR)jcstr, length, rtn,(length*+), NULL, NULL );
     if( size <=  )
         return NULL;
     (env)->ReleaseStringChars(jstr, jcstr );
     rtn[size] = ;
     return rtn;
 }

 //char* ->jstring
 jstring charptrTojstring( JNIEnv* env, const char* str )
 {//gb2312转换成utf8/16
     jstring rtn = ;
     int slen = strlen(str);
     unsigned short * buffer = ;
     if( slen ==  )
         rtn = (env)->NewStringUTF(str );
     else
     {
         int length = MultiByteToWideChar( CP_ACP, , (LPCSTR)str, slen, NULL,  );
         buffer = (unsigned short *)malloc( length* +  );
         if( MultiByteToWideChar( CP_ACP, , (LPCSTR)str, slen, (LPWSTR)buffer, length ) > )
             rtn = (env)->NewString(  (jchar*)buffer, length );
     }
     if( buffer )
         free( buffer );
     return rtn;
 }

 //jchar ->char
 char jchartochar( jchar c )
 {
     char ch = (char)(c & 0x00ff);
     return ch;
 }

 //char* ->jchar
 jchar charTojchar( char c )
 {
     jchar ch = (jchar)(c | 0xff00);
     return ch;
 }

 //char ->C#
 System::Char chartoChar( char c )
 {
     System::Char C = (System::Char)((int)(c));
     return C;
 }

 //C#->char
 char Chartochar( System::Char c )
 {
     char C = (char)((int)(c));
     return C;
 }

增加修改java对象内部成员变量的方法

 void SetjstringField( JNIEnv* env,jobject o, const char* fieldID, const char* value )
 {
     jclass cls = env->GetObjectClass(o);
     jfieldID reInfo = env->GetFieldID(cls,fieldID,
 "Ljava/lang/String;");
     jstring re = charptrTojstring(env,value);
     env->SetObjectField(o,reInfo,re);
 }