假如jni中定义了这么一个接口，用于java将参数传给顶层c，如下
JNIEXPORT jint JNICALL Java_com_init_data(JNIEnv *env, jobject, jstring s)
{
string sId = env->GetStringUTFChars(s, 0);
//char *pId = env->GetStringUTFChars(s, 0);
}
有时候需要底层c将字符串返回给java，如下面的接口定义:
JNIEXPORT jstring JNICALL Java_com_getRegCode(JNIEnv *env, jobject)
{
string strRegisterCode=“1234567890”;
jclass strClass = (env)->FindClass(“java/lang/String”);
jmethodID ctorID = (env)->GetMethodID(strClass, “”, “([BLjava/lang/String;)V”);
jbyteArray bytes = (env)->NewByteArray(strRegisterCode.size());
(env)->SetByteArrayRegion(bytes, 0, strRegisterCode.size(), (jbyte *) strRegisterCode.c_str());
jstring encoding = (env)->NewStringUTF(“GB2312”);
return (jstring) (env)->NewObject(strClass, ctorID, bytes, encoding);
}
