C代码：
   JNIEXPORT jstring JNICALL Java_Sample1_stringMethod(JNIEnv *env, jobject obj, jstring string)
      {
         const char *str = (*env)->GetStringUTFChars(env, string, 0);
         char cap[128];
         strcpy(cap, str);
         (*env)->ReleaseStringUTFChars(env, string, str);
       int i=0;
       for(i=0;i
         *(cap+i)=(char)toupper(*(cap+i));
       return (*env)->NewStringUTF(env, cap);
    }
C++代码：

   JNIEXPORT jstring JNICALL Java_Sample1_stringMethod(JNIEnv *env, jobject obj, jstring string)
      {
         const char *str = (env)->GetStringUTFChars(string, 0);
         char cap[128];
         strcpy(cap, str);
         (env)->ReleaseStringUTFChars(string, str);
       int i=0;
       for(i=0;i
         *(cap+i)=(char)toupper(*(cap+i));
       return (env)->NewStringUTF(cap);
    }