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从Ignite看Cassandra的Blob

cassandra-3.0 ignite cassandra c++
  •  0
  • Vishal Sharma  · 技术社区  · 7 年前

    我试图从Ignite(充当缓存)读取Cassandra表的内容。 下表所示: 

    CREATE TABLE test.epc_table (
    imsi text PRIMARY KEY,
    data blob
)

    该数据blob用于存储C++类对象(类名为“RtCassEpcTableDataVo”)。

    我试图使用下面的c++程序来传递“imsi”的值并获得相应的“data”。 

    #include "ignite/ignite.h"
#include "ignite/ignition.h"


#include <iostream>
#include<string>

#include "RtCassEpcTableDataVo.hpp"

using namespace ignite;
using namespace cache;
using namespace std;

int main()
{
        IgniteConfiguration cfg;

        cfg.springCfgPath = "/home/ignite/apache-ignite-fabric-2.4.0-bin/config/cassandra-config.xml";

        try
        {
                // Start a node.
                Ignite ignite = Ignition::Start(cfg);
Cache<string,RtCassEpcTableDataVo> cache = ignite.GetCache<std::string, RtCassEpcTableDataVo>("cache1");

cout<<endl<<"Enter IMSI : ";
string l_imsi;
getline(cin>>ws,l_imsi);

RtCassEpcTableDataVo l_blob=cache.Get(l_imsi);
                Ignition::StopAll(false);
        }
        catch (IgniteError& err)
        {
                std::cout << "An error occurred: " << err.GetText() << std::endl;

                return err.GetCode();
        }

        std::cout << std::endl;

        return 0;
}

    但是,我遇到了编译错误。 

    In file included from /usr/local/include/ignite/impl/binary/binary_writer_impl.h:32:0,
                 from /usr/local/include/ignite/binary/binary_raw_writer.h:30,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/cache/query/query_scan.h:29,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/impl/cache/cache_impl.h:21,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/impl/ignite_impl.h:27,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/ignite.h:26,
                 from sample.cpp:1:
/usr/local/include/ignite/impl/binary/binary_utils.h: In instantiation of âstatic T ignite::impl::binary::BinaryUtils::GetDefaultValue() [with T = RtCassEpcTableDataVo]â:
/home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/impl/operations.h:349:62:   required from âvoid ignite::impl::Out1Operation<T>::SetNull() [with T = RtCassEpcTableDataVo]â
sample.cpp:72:1:   required from here
/usr/local/include/ignite/impl/binary/binary_utils.h:475:59: error: âGetNullâ is not a member of âignite::binary::BinaryType<RtCassEpcTableDataVo>â
                     ignite::binary::BinaryType<T>::GetNull(res);
                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
In file included from /usr/local/include/ignite/impl/binary/binary_object_impl.h:31:0,
                 from /usr/local/include/ignite/impl/binary/binary_writer_impl.h:35,
                 from /usr/local/include/ignite/binary/binary_raw_writer.h:30,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/cache/query/query_scan.h:29,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/impl/cache/cache_impl.h:21,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/impl/ignite_impl.h:27,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/ignite.h:26,
                 from sample.cpp:1:
/usr/local/include/ignite/impl/binary/binary_reader_impl.h: In instantiation of âvoid ignite::impl::binary::BinaryReaderImpl::ReadTopObject0(T&) [with T = RtCassEpcTableDataVo]â:
/usr/local/include/ignite/impl/binary/binary_type_impl.h:100:17:   required from âstatic T ignite::binary::ReadHelper<T>::Read(R&) [with R = ignite::impl::binary::BinaryReaderImpl; T = RtCassEpcTableDataVo]â
/usr/local/include/ignite/impl/binary/binary_reader_impl.h:887:63:   required from âT ignite::impl::binary::BinaryReaderImpl::ReadTopObject() [with T = RtCassEpcTableDataVo]â
/home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/impl/operations.h:344:21:   required from âvoid ignite::impl::Out1Operation<T>::ProcessOutput(ignite::impl::binary::BinaryReaderImpl&) [with T = RtCassEpcTableDataVo]â
sample.cpp:72:1:   required from here
/usr/local/include/ignite/impl/binary/binary_reader_impl.h:1001:40: error: âReadâ is not a member of âBType {aka ignite::binary::BinaryType<RtCassEpcTableDataVo>}â
                             BType::Read(reader, res);
                             ~~~~~~~~~~~^~~~~~~~~~~~~
/usr/local/include/ignite/impl/binary/binary_reader_impl.h: In instantiation of âT ignite::impl::binary::BinaryReaderImpl::GetNull() const [with T = RtCassEpcTableDataVo]â:
/usr/local/include/ignite/impl/binary/binary_reader_impl.h:905:45:   required from âvoid ignite::impl::binary::BinaryReaderImpl::ReadTopObject0(T&) [with T = RtCassEpcTableDataVo]â
/usr/local/include/ignite/impl/binary/binary_type_impl.h:100:17:   required from âstatic T ignite::binary::ReadHelper<T>::Read(R&) [with R = ignite::impl::binary::BinaryReaderImpl; T = RtCassEpcTableDataVo]â
/usr/local/include/ignite/impl/binary/binary_reader_impl.h:887:63:   required from âT ignite::impl::binary::BinaryReaderImpl::ReadTopObject() [with T = RtCassEpcTableDataVo]â
/home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/impl/operations.h:344:21:   required from âvoid ignite::impl::Out1Operation<T>::ProcessOutput(ignite::impl::binary::BinaryReaderImpl&) [with T = RtCassEpcTableDataVo]â
sample.cpp:72:1:   required from here
/usr/local/include/ignite/impl/binary/binary_reader_impl.h:1024:59: error: âGetNullâ is not a member of âignite::binary::BinaryType<RtCassEpcTableDataVo>â
                     ignite::binary::BinaryType<T>::GetNull(res);
                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
In file included from /usr/local/include/ignite/impl/binary/binary_writer_impl.h:30:0,
                 from /usr/local/include/ignite/binary/binary_raw_writer.h:30,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/cache/query/query_scan.h:29,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/impl/cache/cache_impl.h:21,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/impl/ignite_impl.h:27,
                 from /home/ignite/apache-ignite-fabric-2.4.0-bin/platforms/cpp/core/include/ignite/ignite.h:26,
                 from sample.cpp:1:
/usr/local/include/ignite/impl/binary/binary_id_resolver.h: In instantiation of âint32_t ignite::impl::binary::TemplatedBinaryIdResolver<T>::GetTypeId() [with T = RtCassEpcTableDataVo; int32_t = int]â:
sample.cpp:72:1:   required from here
/usr/local/include/ignite/impl/binary/binary_id_resolver.h:88:68: error: âGetTypeIdâ is not a member of âignite::binary::BinaryType<RtCassEpcTableDataVo>â
                     return ignite::binary::BinaryType<T>::GetTypeId();
                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/usr/local/include/ignite/impl/binary/binary_id_resolver.h: In instantiation of âint32_t ignite::impl::binary::TemplatedBinaryIdResolver<T>::GetFieldId(int32_t, const char*) [with T = RtCassEpcTableDataVo; int32_t = int]â:
sample.cpp:72:1:   required from here
/usr/local/include/ignite/impl/binary/binary_id_resolver.h:94:73: error: âGetFieldIdâ is not a member of âignite::binary::BinaryType<RtCassEpcTableDataVo>â
                         return ignite::binary::BinaryType<T>::GetFieldId(name);
                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~

    持久性设置。xml如下所示: 

    <persistence keyspace="test" table="epc_table">
    <keyPersistence class="java.lang.String" strategy="PRIMITIVE" column="imsi"/>
    <valuePersistence column="data" />
</persistence>

    我不明白为什么这个程序在其他一些表上使用时会起作用(cpp和persistence setting.xml中有一些小的变化)。 

    CREATE TABLE test.table2 (
    imsi text PRIMARY KEY,
    data int
)

    继续: Integrating Apache Cassandra with Apache Ignite

    1 回复  |  直到 7 年前
        1
  •  1
  •   sk0x50    7 年前

    看起来你没有提供 BinaryType 类型模板 RtCassEpcTableDataVo .如下所示: 

    class RtCassEpcTableDataVo {
    friend struct ignite::binary::BinaryType<RtCassEpcTableDataVo>;
    ...
}

template<> struct ignite::binary::BinaryType<RtCassEpcTableDataVo> {
  static void Write(BinaryWriter& writer, const RtCassEpcTableDataVo& obj) {
    // writing data
    // writer.Write...("attributename", obj.GetAttribute());
  }    

  static void Read(BinaryReader& reader, RtCassEpcTableDataVo& dst) {
      // reading data
      // dst.attribute = reader.Read...("attributename");
  }

  ...
}

    全面的描述和示例可在此处找到: Object Serialization

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