Java 8日期/时间（JSR-310）类型与Spring Data MongoDB的映射 [英] Java 8 Date/Time (JSR-310) types mapping with Spring Data MongoDB

问题描述

我有Java 8日期/时间字段的简单文档

I have simple document with Java 8 date/time fields

@Document
public class Token {
    private Instant createdAt;
    ...
}

我想坚持使用Spring Data MongoDB版本1.5。但是 java.time.Instant 类型的字段无法正确反序列化，因为 MappingMongoConverter 缺少<$ c的转换器$ c> java.time 类。

that I want to persist with Spring Data MongoDB version 1.5. But fields of type java.time.Instant could not be de-serialized correctly because MappingMongoConverter lacks converters for java.time classes.

在Spring 4中，我找到了 org.springframework.format.datetime.standard.DateTimeConverters ，其中包含不同的转换器包括 InstantToLongConverter 和 LongToInstantConverter 声明为私有静态类。

In Spring 4 I found org.springframework.format.datetime.standard.DateTimeConverters with different Converters including InstantToLongConverter and LongToInstantConverter declared as private static classes.

如何配置 MongoTemplate 使用它们来映射 Instant 字段到多头？

How can I configure MongoTemplate to use them to map Instant fields to longs?

推荐答案

我不知道这是不是最好的方法，但我添加了Java 8 Date / Time （JSR-310）类型支持Spring Data MongoDB 1.5.0.RELEASE ，如下所示：

I don't know if this is the best way but I added Java 8 Date/Time (JSR-310) types support to Spring Data MongoDB 1.5.0.RELEASE like this:

1. 第一步。添加简单的Spring 转换器 s

public class InstantToLongConverter implements Converter<Instant, Long> {
    @Override
    public Long convert(Instant instant) {
        return instant.toEpochMilli();
    }
}

public class LongToInstantConverter implements Converter<Long, Instant> {
    @Override
    public Instant convert(Long source) {
        return Instant.ofEpochMilli(source);
    }
}

public class LocalDateToStringConverter implements Converter<LocalDate, String> {
    @Override
    public String convert(LocalDate localDate) {
        return localDate.toString();
    }
}

public class StringToLocalDateConverter implements Converter<String, LocalDate> {
    @Override
    public LocalDate convert(String source) {
        return LocalDate.parse(source);
    }
}

第二步。在 AbstractMongoConfiguration 实现中使用 MappingMongoConverter 注册这些自定义转换器像这样：

Second step. Register these custom Converters with MappingMongoConverter in your AbstractMongoConfiguration implementation like this:

@Configuration
@EnableMongoRepositories(basePackages = {"my.app.repository"})
public class MongoConfiguration extends AbstractMongoConfiguration {

    ...

    @Override
    public CustomConversions customConversions() {
        return new CustomConversions(Arrays.asList(
                new InstantToLongConverter(), new LongToInstantConverter(),
                new LocalDateToStringConverter(), new StringToLocalDateConverter()));
    }
}

现在，您的文档的 Instant 字段将作为长值保留，而 LocalDate 将作为字符串保留。

Now your document's Instant fields will be persisted as long values and LocalDates as Strings.

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