我有一个枚举字段,我想映射到 cassandra 中的一个列
public enum MyEnum {
Aa,
Bb,
Cc,
}
这是我注册的方式
CodecRegistry myCodecRegistry = new CodecRegistry();
myCodecRegistry.register(new EnumOrdinalCodec<MyEnum>(MyEnum.class));
cluster = Cluster.builder().addContactPoint(cassandraHosts).withPort(cassandraPort).withCodecRegistry(myCodecRegistry).build();
我能够很好地连接到 cassandra。这是模型类的片段
public class MyModel
{
@PartitionKey
@Column(name="id")
private String id;
@ClusteringColumn
@Column(name="name")
private String name = "";
@Column(name="enum")
private MyEnum enum;
public MyModel(String i, String n)
{
id=i;
name=n
enum=MyEnum.Aa;
}
}
下面是我如何使用 CQL 创建表
CREATE TABLE IF NOT EXISTS
tab
(
name varchar ,
id varchar,
enum varchar,
PRIMARY KEY ((id), name));
终于有了我的映射代码
manager = new MappingManager(session);
mapper = manager.mapper(MyModel.class);
accessor = manager.createAccessor(MyAccessor.class);
这里是 MyAccessor
@Accessor
public interface MyAccessor{
@Query("SELECT * FROM case WHERE id=? and name=? ALLOW FILTERING;")
MyModel readByIdAndName(String id,String name);
}
所以当我尝试执行
MyModel m = new MyModel("asdasf","qw");
mapper.save(m);
我明白了
com.datastax.driver.core.exceptions.CodecNotFoundException: Codec not found for requested operation: [varchar <-> my.pack.MyEnum]
at com.datastax.driver.core.exceptions.CodecNotFoundException.copy(CodecNotFoundException.java:56)
at com.datastax.driver.core.exceptions.CodecNotFoundException.copy(CodecNotFoundException.java:25)
at com.datastax.driver.mapping.DriverThrowables.propagateCause(DriverThrowables.java:41)
at com.datastax.driver.mapping.Mapper.save(Mapper.java:289)
我做错了什么?
最佳答案
EnumOrdinalCodec 仅用于 int <-> Enum 之间的映射。由于您的 Enum 是基于字符串的,因此请改用 EnumNameCodec
类。这两个编解码器类的 Javadoc 如下所示。希望对您有所帮助。
枚举名称解码器
A codec that serializes Enum instances as CQL varchars representing their programmatic names as returned by Enum.name().
枚举顺序编解码器
A codec that serializes Enum instances as CQL ints representing their ordinal values as returned by Enum.ordinal().
链接到 Javadoc
关于java - Cassandra CodecNotFoundException : Codec not found for requested operation,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/47996457/