Question

具有下表

  "CREATE TABLE IF NOT EXISTS user_preferences (" +
                        "    user_id text," +
                        "    my_duration duration," +
                        "    last_modified timestamp," +
                        "    primary key((id))" +
                        ");";

当尝试保留以下模型时

import com.datastax.driver.mapping.annotations.Column;
import com.datastax.driver.mapping.annotations.PartitionKey;
import com.datastax.driver.mapping.annotations.Table;
import java.time.Duration;

@Table(name = "user_preferences")
public class UserPreferences {

    @PartitionKey
    @Column(name = "user_id")
    private String userId;

    @Column(name = "my_duration")
    private Duration myDuration;

    @Column(name = "last_modified")
    private Date lastModified;
}

我得到此编解码器未找到的异常。

com.datastax.driver.core.exceptions.CodecNotFoundException: Codec not found for requested operation: [duration <-> java.time.Duration]
    at com.datastax.driver.core.exceptions.CodecNotFoundException.copy(CodecNotFoundException.java:57) ~[cassandra-driver-core-3.6.0.jar:na]
    at com.datastax.driver.core.exceptions.CodecNotFoundException.copy(CodecNotFoundException.java:25) ~[cassandra-driver-core-3.6.0.jar:na]
    at com.datastax.driver.mapping.DriverThrowables.propagateCause(DriverThrowables.java:39) ~[cassandra-driver-mapping-3.6.0.jar:na]
    at com.datastax.driver.mapping.Mapper.save(Mapper.java:356) ~[cassandra-driver-mapping-3.6.0.jar:na]

注意：读取工作正常，可能是因为尚未填充表格。

Datastax-core 3.3.2是否支持java.time.Duration？

Answer 1

评论的补充：默认编解码器返回com.datastax.driver.core.Duration！ C *持续时间与java.time.Duration不兼容。因此，您应该在代码中使用驱动程序Duration类型，或者提供自己的编解码器。

这个特定问题的答案有误，但如果您想实现自己的编解码器仍然很有用，则必须以这种方式进行注册。

对于其他java.time类，您需要使用/注册额外的jdk8编解码器： https://docs.datastax.com/en/developer/java-driver/3.1/manual/custom_codecs/extras/

import com.datastax.driver.extras.codecs.jdk8.InstantCodec;
import java.time.Instant;

cluster.getConfiguration().getCodecRegistry()
    .register(InstantCodec.instance);

或者如果您无权访问群集对象

com.datastax.driver.core.CodecRegistry.DEFAULT_INSTANCE.register(InstantCodec.instance);

找不到请求的操作的编解码器：[duration <-> java.time.Duration]

1 个答案: