First Time: In C++ server,I Use capnp::DynamicStruct, code like this: capnp::MallocMessageBuilder msg; capnp::DynamicStruct::Builder fullinfo_builder = msg.initRoot<capnp::DynamicStruct>(g_schema); capnp::DynamicStruct::Builder fullInfo = msg.initRoot<capnp::DynamicStruct>(g_schema);
capnp::messageToFlatArray(msg); ---->convert it to char* send to java_cliet Java Client ,code like this: MessageReader message = org.capnproto.Serialize.read(capn_object_bytes.asReadOnlyByteBuffer());, Info.Reader adInfo = message.getRoot(Info.factory); Above ， My First Time do work , but The Second Time, I do like this ,it do not work: In C++ server, code like this: capnp::MallocMessageBuilder message; Info::Builder info = message.initRoot<Info>(); info.setId(123); kj::ArrayPtr<const kj::ArrayPtr<const capnp::word>> segments = message.getSegmentsForOutput(); then I convert the segments object to char* send to java_client by proto rpc_call (bytes field) Java Client ,code like this: MessageReader message = org.capnproto.Serialize.read(capn_object_bytes.asReadOnlyByteBuffer());, Info.Reader adInfo = message.getRoot(Info.factory); In Second Time, happen Error like this: Exception in thread "main" java.lang.IllegalArgumentException at java.nio.Buffer.limit(Buffer.java:275) at org.capnproto.Serialize.read(Serialize.java:140) at org.capnproto.Serialize.read(Serialize.java:111) How Can I do , In Second Time ,thanks 在 2019年9月30日星期一 UTC+8下午8:29:41，David Renshaw写道： > > On the Java side, you need to first read the bytes into a `MessageReader`. > That's typically done via one of the `Serialize.read()` methods. > > The `AnyPointer.Reader()` is not intended for external use. Probably we > should make it private. > > > On Mon, Sep 30, 2019 at 6:25 AM 张小 <[email protected] <javascript:>> wrote: > >> C++ server send Capn Object to JavaClient like this >> >> capnp::MallocMessageBuilder message; >> Info::Builder info = message.initRoot<Info>(); >> info.setId(123); >> kj::ArrayPtr<const kj::ArrayPtr<const capnp::word>> segments = >> message.getSegmentsForOutput(); >> >> then I convert the segments object to char* send to java_client by >> proto rpc_call (bytes field) >> >> >> Then In java_client, I do like this to read the capn object >> com.google.protobuf.ByteString capn_object_bytes = >> response.getCapnObject() >> SegmentReader segment = new >> SegmentReader(capn_object_bytes.asReadOnlyByteBuffer(), null); >> AnyPointer.Reader any = new AnyPointer.Reader(segment, 0, 64*1024*1024); >> Info.Reader info = any.getAs(Info.factory); >> System.out.println("Id:" + info.getId()); >> >> >> run java_cliet ,happend error like this : >> Exception in thread "main" java.lang.NullPointerException >> at org.capnproto.WireHelpers.readStructPointer(WireHelpers.java:918) >> at >> org.capnproto.StructFactory.fromPointerReaderRefDefault(StructFactory.java:34) >> at org.capnproto.StructFactory.fromPointerReader(StructFactory.java:41) >> at org.capnproto.StructFactory.fromPointerReader(StructFactory.java:24) >> at org.capnproto.AnyPointer$Reader.getAs(AnyPointer.java:56) >> >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Cap'n Proto" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/capnproto/081ab20b-5eae-43d5-a4fc-8230ef39d4a5%40googlegroups.com >> >> <https://groups.google.com/d/msgid/capnproto/081ab20b-5eae-43d5-a4fc-8230ef39d4a5%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "Cap'n Proto" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/capnproto/816c3227-c2b2-4b72-8ead-e707759a257c%40googlegroups.com.
