JNI中 Java 中字符串 转换成C中的字符数组方法

char*   Jstring2CStr(JNIEnv*   env,   jstring   jstr)
{
char*   rtn   =   NULL;
jclass   clsstring   =   (*env)->FindClass(env,"java/lang/String");
jstring   strencode   =   (*env)->NewStringUTF(env,"GB2312");
jmethodID   mid   =   (*env)->GetMethodID(env,clsstring,   "getBytes",   "(Ljava/lang/String;)[B");
jbyteArray   barr=   (jbyteArray)(*env)->CallObjectMethod(env,jstr,mid,strencode); // String .getByte("GB2312");
jsize   alen   =   (*env)->GetArrayLength(env,barr);
jbyte*   ba   =   (*env)->GetByteArrayElements(env,barr,JNI_FALSE);
if(alen   >   0)
{
rtn   =   (char*)malloc(alen+1);         //"\0"
memcpy(rtn,ba,alen);
rtn[alen]=0;
}
(*env)->ReleaseByteArrayElements(env,barr,ba,0);  //
return rtn;
}