jstring 和string char*之间的转换

转载来源：http://dncsoft.iteye.com/blog/1010213

#include <malloc.h>
#include <string.h>
#include <stdlib.h>
#include <vcclr.h>

using namespace System;
using namespace System::Text;

// jstring To String
String^ jstringToStr(JNIEnv* env, jstring jstr)
{
char* str = jstringTostring(env, jstr);
String^ value = gcnew String(str);
free(str);
return value;
}

// jstring To char*
char* jstringTostring(JNIEnv* env, jstring jstr)
{
char* rtn = NULL;
jclass clsstring = env->FindClass("java/lang/String");
jstring strencode = env->NewStringUTF("utf-8");
jmethodID mid = env->GetMethodID(clsstring, "getBytes", "(Ljava/lang/String;)[B");
jbyteArray barr = (jbyteArray)env->CallObjectMethod(jstr, mid, strencode);
jsize alen = env->GetArrayLength(barr);
jbyte* ba = env->GetByteArrayElements(barr, JNI_FALSE);
if (alen > 0)
{
rtn = (char*)malloc(alen + 1);
memcpy(rtn, ba, alen);
rtn[alen] = 0;
}
env->ReleaseByteArrayElements(barr, ba, 0);
return rtn;
}

// String To jstring
jstring strTojstring(JNIEnv* env, String^ rtn)
{
pin_ptr<const wchar_t> wch = PtrToStringChars(rtn);
size_t convertedChars = 0;
size_t sizeInBytes = ((rtn->Length + 1) * 2);
char *ch = (char *)malloc(sizeInBytes);
errno_t err = wcstombs_s(&convertedChars,
ch, sizeInBytes,
wch, sizeInBytes);
jstring js = stringTojstring(env, ch);
free(ch);
return js;
}

// char* To jstring
jstring stringTojstring(JNIEnv* env, const char* pat)
{
jclass strClass = env->FindClass("Ljava/lang/String;");
jmethodID ctorID = env->GetMethodID(strClass, "<init>", "([BLjava/lang/String;)V");
jbyteArray bytes = env->NewByteArray(strlen(pat));
env->SetByteArrayRegion(bytes, 0, strlen(pat), (jbyte*)pat);
jstring encoding = env->NewStringUTF("utf-8");
return (jstring)env->NewObject(strClass, ctorID, bytes, encoding);
}