转：JNI jstring与c++字符串类型转换函数

jstring与c++字符串类型转换函数

jstring str2jstring(JNIEnv* env,const char* pat)
{//定义java String类 strClassjclass strClass = (env)->FindClass("Ljava/lang/String;");//获取String(byte[],String)的构造器,用于将本地byte[]数组转换为一个新StringjmethodID ctorID = (env)->GetMethodID(strClass, "<init>", "([BLjava/lang/String;)V");//建立byte数组jbyteArray bytes = (env)->NewByteArray(strlen(pat));//将char* 转换为byte数组(env)->SetByteArrayRegion(bytes, 0, strlen(pat), (jbyte*)pat);// 设置String, 保存语言类型,用于byte数组转换至String时的参数jstring encoding = (env)->NewStringUTF("GB2312"); //将byte数组转换为java String,并输出return (jstring)(env)->NewObject(strClass, ctorID, bytes, encoding);
}std::string jstring2str(JNIEnv* env, jstring jstr)
{   char*   rtn   =   NULL;   jclass   clsstring   =   env->FindClass("java/lang/String");   jstring   strencode   =   env->NewStringUTF("GB2312");   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);   std::string stemp(rtn);free(rtn);return   stemp;   
}