如何使用映射管理器将 java.sql.Date 存储在 cassandra 日期字段中?

问题描述

有人可以帮助我使用 Java 将当前系统日期以 yyyy-mm-dd 格式存储在 cassandra 日期列中吗?使用 MappingManager 保存 java.sql.Date 时出现异常.

Can someone help me to store the current system date in cassandra date column in format yyyy-mm-dd using Java? I get exception while saving the java.sql.Date using MappingManager.

我的示例程序是:

Test.java

import com.datastax.driver.mapping.annotations.Table;
import java.sql.Date;
@Table(keyspace = "testing", name = "test")
public class Test {

    private String uid;
    private Date rece;

    public String getUid() {
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }

    public Date getRece() {
        return rece;
    }

    public void setRece(Date rece) {
        this.rece = rece;
    }


}

TestDao.java

Mapper mapper = new MappingManager(session).mapper(Test.class);
mapper.save(test);

Cassandra 架构:

CREATE TABLE tokenizer.test (
    id text PRIMARY KEY,
    testdate date
) ;

推荐答案

将 rece 的数据类型声明为 com.datastax.driver.core.LocalDate或编写自定义编解码器对 java.sql.Date 进行编码并将其注册到集群.

Either declare data type of rece to com.datastax.driver.core.LocalDate or Write a custom codec to encode java.sql.Date and register it to the cluster.

自定义编解码器示例:

import com.datastax.driver.core.LocalDate;
import com.datastax.driver.core.ProtocolVersion;
import com.datastax.driver.core.TypeCodec;
import com.datastax.driver.core.exceptions.InvalidTypeException;

import java.nio.ByteBuffer;
import java.sql.Date;


public class DateCodec extends TypeCodec<Date> {

    private final TypeCodec<LocalDate> innerCodec;

    public DateCodec(TypeCodec<LocalDate> codec, Class<Date> javaClass) {
        super(codec.getCqlType(), javaClass);
        innerCodec = codec;
    }

    @Override
    public ByteBuffer serialize(Date value, ProtocolVersion protocolVersion) throws InvalidTypeException {
        return innerCodec.serialize(LocalDate.fromMillisSinceEpoch(value.getTime()), protocolVersion);
    }

    @Override
    public Date deserialize(ByteBuffer bytes, ProtocolVersion protocolVersion) throws InvalidTypeException {
        return new Date(innerCodec.deserialize(bytes, protocolVersion).getMillisSinceEpoch());
    }

    @Override
    public Date parse(String value) throws InvalidTypeException {
        return new Date(innerCodec.parse(value).getMillisSinceEpoch());
    }

    @Override
    public String format(Date value) throws InvalidTypeException {
        return value.toString();
    }
}

如何使用?

示例:

CodecRegistry codecRegistry = new CodecRegistry();
codecRegistry.register(new DateCodec(TypeCodec.date(), Date.class));

try (Cluster cluster = Cluster.builder().withCodecRegistry(codecRegistry).addContactPoint("127.0.0.1").withCredentials("cassandra", "cassandra").build(); Session session = cluster.connect("test")) {
    Mapper mapper = new MappingManager(session).mapper(Test.class);
    mapper.save(test);
}

这篇关于如何使用映射管理器将 java.sql.Date 存储在 cassandra 日期字段中?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！